Author name code: bahcall
ADS astronomy entries on 2022-09-14
author:Bahcall, John N.
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Title: The Search for Muon Neutrinos from Northern Hemisphere
Gamma-Ray Bursts with AMANDA
Authors: Achterberg, A.; Ackermann, M.; Adams, J.; Ahrens, J.; Andeen,
K.; Auffenberg, J.; Bahcall, J. N.; Bai, X.; Baret, B.; Barwick,
S. W.; Bay, R.; Beattie, K.; Becka, T.; Becker, J. K.; Becker,
K. -H.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.;
Besson, D. Z.; Blaufuss, E.; Boersma, D. J.; Bohm, C.; Bolmont, J.;
Böser, S.; Botner, O.; Bouchta, A.; Braun, J.; Burgess, C.; Burgess,
T.; Castermans, T.; Chirkin, D.; Christy, B.; Clem, J.; Cowen, D. F.;
D'Agostino, M. V.; Davour, A.; Day, C. T.; De Clercq, C.; Demirörs,
L.; Descamps, F.; Desiati, P.; DeYoung, T.; Diaz-Velez, J. C.;
Dreyer, J.; Dumm, J. P.; Duvoort, M. R.; Edwards, W. R.; Ehrlich,
R.; Eisch, J.; Ellsworth, R. W.; Evenson, P. A.; Fadiran, O.; Fazely,
A. R.; Filimonov, K.; Foerster, M. M.; Fox, B. D.; Franckowiak, A.;
Gaisser, T. K.; Gallagher, J.; Ganugapati, R.; Geenen, H.; Gerhardt,
L.; Goldschmidt, A.; Goodman, J. A.; Gozzini, R.; Griesel, T.;
Gross, A.; Grullon, S.; Gunasingha, R. M.; Gurtner, M.; Hallgren,
A.; Halzen, F.; Han, K.; Hanson, K.; Hardtke, D.; Hardtke, R.; Hart,
J. E.; Hasegawa, Y.; Hauschildt, T.; Hays, D.; Heise, J.; Helbing,
K.; Hellwig, M.; Herquet, P.; Hill, G. C.; Hodges, J.; Hoffman,
K. D.; Hommez, B.; Hoshina, K.; Hubert, D.; Hughey, B.; Hulth, P. O.;
Hülss, J. -P.; Hultqvist, K.; Hundertmark, S.; Inaba, M.; Ishihara,
A.; Jacobsen, J.; Japaridze, G. S.; Johansson, H.; Jones, A.; Joseph,
J. M.; Kampert, K. -H.; Kappes, A.; Karg, T.; Karle, A.; Kawai, H.;
Kelley, J. L.; Kitamura, N.; Klein, S. R.; Klepser, S.; Kohnen, G.;
Kolanoski, H.; Köpke, L.; Kowalski, M.; Kowarik, T.; Krasberg, M.;
Kuehn, K.; Labare, M.; Landsman, H.; Leich, H.; Leier, D.; Liubarsky,
I.; Lundberg, J.; Lünemann, J.; Madsen, J.; Mase, K.; Matis, H. S.;
McCauley, T.; McParland, C. P.; Meli, A.; Messarius, T.; Mészáros,
P.; Miyamoto, H.; Mokhtarani, A.; Montaruli, T.; Morey, A.; Morse,
R.; Movit, S. M.; Münich, K.; Nahnhauer, R.; Nam, J. W.; Niessen,
P.; Nygren, D. R.; Ögelman, H.; Olivas, A.; Patton, S.; Peña-Garay,
C.; Pérez de los Heros, C.; Piegsa, A.; Pieloth, D.; Pohl, A. C.;
Porrata, R.; Pretz, J.; Price, P. B.; Przybylski, G. T.; Rawlins, K.;
Razzaque, S.; Resconi, E.; Rhode, W.; Ribordy, M.; Rizzo, A.; Robbins,
S.; Roth, P.; Rott, C.; Rutledge, D.; Ryckbosch, D.; Sander, H. -G.;
Sarkar, S.; Schlenstedt, S.; Schmidt, T.; Schneider, D.; Seckel, D.;
Semburg, B.; Seo, S. H.; Seunarine, S.; Silvestri, A.; Smith, A. J.;
Solarz, M.; Song, C.; Sopher, J. E.; Spiczak, G. M.; Spiering, C.;
Stamatikos, M.; Stanev, T.; Steffen, P.; Stezelberger, T.; Stokstad,
R. G.; Stoufer, M. C.; Stoyanov, S.; Strahler, E. A.; Straszheim, T.;
Sulanke, K. -H.; Sullivan, G. W.; Sumner, T. J.; Taboada, I.; Tarasova,
O.; Tepe, A.; Thollander, L.; Tilav, S.; Tluczykont, M.; Toale, P. A.;
Turčan, D.; van Eijndhoven, N.; Vandenbroucke, J.; Van Overloop, A.;
Viscomi, V.; Voigt, B.; Wagner, W.; Walck, C.; Waldmann, H.; Walter,
M.; Wang, Y. -R.; Wendt, C.; Wiebusch, C. H.; Wikström, G.; Williams,
D. R.; Wischnewski, R.; Wissing, H.; Woschnagg, K.; Xu, X. W.; Yodh,
G.; Yoshida, S.; Zornoza, J. D.; Interplanetary Network, The
Bibcode: 2008ApJ...674..357A
Altcode: 2007arXiv0705.1186T
We present the results of the analysis of neutrino observations by
the Antarctic Muon and Neutrino Detector Array (AMANDA) correlated
with photon observations of more than 400 gamma-ray bursts (GRBs) in
the northern hemisphere from 1997 to 2003. During this time period,
AMANDA's effective collection area for muon neutrinos was larger
than that of any other existing detector. After the application of
various selection criteria to our data, we expect ~1 neutrino event
and <2 background events. Based on our observations of zero events
during and immediately prior to the GRBs in the data set, we set
the most stringent upper limit on muon neutrino emission correlated
with GRBs. Assuming a Waxman-Bahcall spectrum and incorporating all
systematic uncertainties, our flux upper limit has a normalization at
1 PeV of E2Φν <= 6.3 × 10-9
GeV cm-2 s-1 sr-1, with 90% of the
events expected within the energy range of ~10 TeV to ~3 PeV. The impact
of this limit on several theoretical models of GRBs is discussed, as
well as the future potential for detection of GRBs by next-generation
neutrino telescopes. Finally, we briefly describe several modifications
to this analysis in order to apply it to other types of transient
point sources.
Title: IceCube contributions to the XIV International Symposium on
Very High Energy Cosmic Ray Interactions (ISVHECRI 2006)
Authors: IceCube Collaboration; Achterberg, A.; Ackermann, M.; Adams,
J.; Ahrens, J.; Andeen, K.; Atlee, D. W.; Bahcall, J. N.; Bai, X.;
Baret, B.; Barwick, S. W.; Bay, R.; Beattie, K.; Becka, T.; Becker,
J. K.; Becker, K. -H.; Berghaus, P.; Berley, D.; Bernardini, E.;
Bertrand, D.; Besson, D. Z.; Blaufuss, E.; Boersma, D. J.; Bohm,
C.; Bolmont, J.; Böser, S.; Botner, O.; Bouchta, A.; Braun, J.;
Burgess, C.; Burgess, T.; Castermans, T.; Chirkin, D.; Christy, B.;
Clem, J.; Cowen, D. F.; D'Agostino, M. V.; Davour, A.; Day, C. T.;
de Clercq, C.; Demirörs, L.; Descamps, F.; Desiati, P.; Deyoung, T.;
Diaz-Velez, J. C.; Dreyer, J.; Dumm, J. P.; Duvoort, M. R.; Edwards,
W. R.; Ehrlich, R.; Eisch, J.; Ellsworth, R. W.; Evenson, P. A.;
Fadiran, O.; Fazely, A. R.; Feser, T.; Filimonov, K.; Fox, B. D.;
Gaisser, T. K.; Gallagher, J.; Ganugapati, R.; Geenen, H.; Gerhardt,
L.; Goldschmidt, A.; Goodman, J. A.; Gozzini, R.; Grullon, S.; Groß,
A.; Gunasingha, R. M.; Gurtner, M.; Hallgren, A.; Halzen, F.; Han,
K.; Hanson, K.; Hardtke, D.; Hardtke, R.; Harenberg, T.; Hart, J. E.;
Hauschildt, T.; Hays, D.; Heise, J.; Helbing, K.; Hellwig, M.; Herquet,
P.; Hill, G. C.; Hodges, J.; Hoffman, K. D.; Hommez, B.; Hoshina, K.;
Hubert, D.; Hughey, B.; Hulth, P. O.; Hultqvist, K.; Hundertmark,
S.; Hülß, J. -P.; Ishihara, A.; Jacobsen, J.; Japaridze, G. S.;
Johansson, H.; Jones, A.; Joseph, J. M.; Kampert, K. -H.; Karle, A.;
Kawai, H.; Kelley, J. L.; Kestel, M.; Kitamura, N.; Klein, S. R.;
Klepser, S.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Krasberg, M.;
Kuehn, K.; Landsman, H.; Leich, H.; Leier, D.; Leuthold, M.; Liubarsky,
I.; Lundberg, J.; Lünemann, J.; Madsen, J.; Mase, K.; Matis, H. S.;
McCauley, T.; McParland, C. P.; Meli, A.; Messarius, T.; Mészáros,
P.; Miyamoto, H.; Mokhtarani, A.; Montaruli, T.; Morey, A.; Morse,
R.; Movit, S. M.; Münich, K.; Nahnhauer, R.; Nam, J. W.; Nießen,
P.; Nygren, D. R.; Ögelman, H.; Olivas, A.; Patton, S.; Peña-Garay,
C.; Pérez de Los Heros, C.; Piegsa, A.; Pieloth, D.; Pohl, A. C.;
Porrata, R.; Pretz, J.; Price, P. B.; Przybylski, G. T.; Rawlins, K.;
Razzaque, S.; Resconi, E.; Rhode, W.; Ribordy, M.; Rizzo, A.; Robbins,
S.; Roth, P.; Rott, C.; Rutledge, D.; Ryckbosch, D.; Sander, H. -G.;
Sarkar, S.; Schlenstedt, S.; Schmidt, T.; Schneider, D.; Seckel, D.;
Seo, S. H.; Seunarine, S.; Silvestri, A.; Smith, A. J.; Solarz, M.;
Song, C.; Sopher, J. E.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.;
Stanev, T.; Steffen, P.; Stezelberger, T.; Stokstad, R. G.; Stoufer,
M. C.; Stoyanov, S.; Strahler, E. A.; Straszheim, T.; Sulanke, K. -H.;
Sullivan, G. W.; Sumner, T. J.; Taboada, I.; Tarasova, O.; Tepe, A.;
Thollander, L.; Tilav, S.; Tluczykont, M.; Toale, P. A.; Turčan, D.;
van Eijndhoven, N.; Vandenbroucke, J.; van Overloop, A.; Voigt, B.;
Wagner, W.; Walck, C.; Waldmann, H.; Walter, M.; Wang, Y. -R.; Wendt,
C.; Wiebusch, C. H.; Wikström, G.; Williams, D. R.; Wischnewski,
R.; Wissing, H.; Woschnagg, K.; Xu, X. W.; Yodh, G.; Yoshida, S.;
Zornoza, J. D.
Bibcode: 2008NuPhS.175..407I
Altcode: 2008NuPhS.175..407A
No abstract at ADS
Title: Search for Neutrino-induced Cascades from Gamma-Ray Bursts
with AMANDA
Authors: Achterberg, A.; Ackermann, M.; Adams, J.; Ahrens, J.; Andeen,
K.; Auffenberg, J.; Bahcall, J. N.; Bai, X.; Baret, B.; Barwick,
S. W.; Bay, R.; Beattie, K.; Becka, T.; Becker, J. K.; Becker,
K. -H.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.;
Besson, D. Z.; Blaufuss, E.; Boersma, D. J.; Bohm, C.; Bolmont, J.;
Böser, S.; Botner, O.; Bouchta, A.; Braun, J.; Burgess, C.; Burgess,
T.; Castermans, T.; Chirkin, D.; Christy, B.; Clem, J.; Cowen, D. F.;
D'Agostino, M. V.; Davour, A.; Day, C. T.; De Clercq, C.; Demirörs,
L.; Descamps, F.; Desiati, P.; De Young, T.; Diaz-Velez, J. C.;
Dreyer, J.; Dumm, J. P.; Duvoort, M. R.; Edwards, W. R.; Ehrlich,
R.; Eisch, J.; Ellsworth, R. W.; Evenson, P. A.; Fadiran, O.; Fazely,
A. R.; Filimonov, K.; Foerster, M. M.; Fox, B. D.; Franckowiak, A.;
Gaisser, T. K.; Gallagher, J.; Ganugapati, R.; Geenen, H.; Gerhardt,
L.; Goldschmidt, A.; Goodman, J. A.; Gozzini, R.; Griesel, T.;
Grullon, S.; Groß, A.; Gunasingha, R. M.; Gurtner, M.; Hallgren,
A.; Halzen, F.; Han, K.; Hanson, K.; Hardtke, D.; Hardtke, R.; Hart,
J. E.; Hasegawa, Y.; Hauschildt, T.; Hays, D.; Heise, J.; Helbing,
K.; Hellwig, M.; Herquet, P.; Hill, G. C.; Hodges, J.; Hoffman,
K. D.; Hommez, B.; Hoshina, K.; Hubert, D.; Hughey, B.; Hulth,
P. O.; Hultqvist, K.; Hülß, J. -P.; Hundertmark, S.; Inaba, M.;
Ishihara, A.; Jacobsen, J.; Japaridze, G. S.; Johansson, H.; Jones,
A.; Joseph, J. M.; Kampert, K. -H.; Karg, T.; Karle, A.; Kawai, H.;
Kelley, J. L.; Kitamura, N.; Klein, S. R.; Klepser, S.; Kohnen, G.;
Kolanoski, H.; Köpke, L.; Kowalski, M.; Kowarik, T.; Krasberg, M.;
Kuehn, K.; Labare, M.; Landsman, H.; Leich, H.; Leier, D.; Liubarsky,
I.; Lundberg, J.; Lünemann, J.; Madsen, J.; Mase, K.; Matis, H. S.;
McCauley, T.; McParland, C. P.; Meli, A.; Messarius, T.; Mészáros,
P.; Miyamoto, H.; Mokhtarani, A.; Montaruli, T.; Morey, A.; Morse,
R.; Movit, S. M.; Münich, K.; Nahnhauer, R.; Nam, J. W.; Nießen,
P.; Nygren, D. R.; Ögelman, H.; Olivas, A.; Patton, S.; Peña-Garay,
C.; Pérez de los Heros, C.; Piegsa, A.; Pieloth, D.; Pohl, A. C.;
Porrata, R.; Pretz, J.; Price, P. B.; Przybylski, G. T.; Rawlins, K.;
Razzaque, S.; Resconi, E.; Rhode, W.; Ribordy, M.; Rizzo, A.; Robbins,
S.; Roth, P.; Rott, C.; Rutledge, D.; Ryckbosch, D.; Sander, H. -G.;
Sarkar, S.; Schlenstedt, S.; Schmidt, T.; Schneider, D.; Seckel, D.;
Semburg, B.; Seo, S. H.; Seunarine, S.; Silvestri, A.; Smith, A. J.;
Solarz, M.; Song, C.; Sopher, J. E.; Spiczak, G. M.; Spiering, C.;
Stamatikos, M.; Stanev, T.; Steffen, P.; Stezelberger, T.; Stokstad,
R. G.; Stoufer, M. C.; Stoyanov, S.; Strahler, E. A.; Straszheim, T.;
Sulanke, K. -H.; Sullivan, G. W.; Sumner, T. J.; Taboada, I.; Tarasova,
O.; Tepe, A.; Thollander, L.; Tilav, S.; Tluczykont, M.; Toale, P. A.;
Turčan, D.; van Eijndhoven, N.; Vandenbroucke, J.; Van Overloop, A.;
Viscomi, V.; Voigt, B.; Wagner, W.; Walck, C.; Waldmann, H.; Walter,
M.; Wang, Y. -R.; Wendt, C.; Wiebusch, C. H.; Wikström, G.; Williams,
D. R.; Wischnewski, R.; Wissing, H.; Woschnagg, K.; Xu, X. W.; Yodh,
G.; Yoshida, S.; Zornoza, J. D.
Bibcode: 2007ApJ...664..397A
Altcode: 2007astro.ph..2265I
Using the neutrino telescope AMANDA-II, we have conducted two
analyses searching for neutrino-induced cascades from gamma-ray
bursts. No evidence of astrophysical neutrinos was found, and limits
are presented for several models. We also present neutrino effective
areas which allow the calculation of limits for any neutrino production
model. The first analysis looked for a statistical excess of events
within a sliding window of 1 or 100 s (for short and long burst
classes, respectively) during the years 2001-2003. The resulting
upper limit on the diffuse flux normalization times E2
for the Waxman-Bahcall model at 1 PeV is 1.6×10-6 GeV
cm-2 s-1 sr-1 (a factor of 120 above
the theoretical prediction). For this search 90% of the neutrinos
would fall in the energy range 50 TeV to 7 PeV. The second analysis
looked for neutrino-induced cascades in coincidence with 73 bursts
detected by BATSE in the year 2000. The resulting upper limit on
the diffuse flux normalization times E2, also at 1 PeV, is
1.5×10-6 GeV cm-2 s-1 sr-1
(a factor of 110 above the theoretical prediction) for the same energy
range. The neutrino-induced cascade channel is complementary to the
up-going muon channel. We comment on its advantages for searches of
neutrinos from GRBs and its future use with IceCube.
Title: Five years of searches for point sources of astrophysical
neutrinos with the AMANDA-II neutrino telescope
Authors: Achterberg, A.; Ackermann, M.; Adams, J.; Ahrens, J.; Andeen,
K.; Atlee, D. W.; Bahcall, J. N.; Bai, X.; Baret, B.; Barwick, S. W.;
Bay, R.; Beattie, K.; Becka, T.; Becker, J. K.; Becker, K. -H.;
Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson,
D. Z.; Blaufuss, E.; Boersma, D. J.; Bohm, C.; Bolmont, J.; Böser,
S.; Botner, O.; Bouchta, A.; Braun, J.; Burgess, C.; Burgess, T.;
Castermans, T.; Chirkin, D.; Christy, B.; Clem, J.; Cowen, D. F.;
D'Agostino, M. V.; Davour, A.; Day, C. T.; de Clercq, C.; Demirörs,
L.; Descamps, F.; Desiati, P.; De Young, T.; Diaz-Velez, J. C.; Dreyer,
J.; Dumm, J. P.; Duvoort, M. R.; Edwards, W. R.; Ehrlich, R.; Eisch,
J.; Ellsworth, R. W.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.;
Feser, T.; Filimonov, K.; Fox, B. D.; Gaisser, T. K.; Gallagher, J.;
Ganugapati, R.; Geenen, H.; Gerhardt, L.; Goldschmidt, A.; Goodman,
J. A.; Gozzini, R.; Grullon, S.; Groß, A.; Gunasingha, R. M.;
Gurtner, M.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Hardtke,
D.; Hardtke, R.; Harenberg, T.; Hart, J. E.; Hauschildt, T.; Hays,
D.; Heise, J.; Helbing, K.; Hellwig, M.; Herquet, P.; Hill, G. C.;
Hodges, J.; Hoffman, K. D.; Hommez, B.; Hoshina, K.; Hubert, D.;
Hughey, B.; Hulth, P. O.; Hultqvist, K.; Hundertmark, S.; Hülß,
J. -P.; Ishihara, A.; Jacobsen, J.; Japaridze, G. S.; Johansson,
H.; Jones, A.; Joseph, J. M.; Kampert, K. -H.; Karle, A.; Kawai, H.;
Kelley, J. L.; Kestel, M.; Kitamura, N.; Klein, S. R.; Klepser, S.;
Kohnen, G.; Kolanoski, H.; Kowalski, M.; Köpke, L.; Krasberg, M.;
Kuehn, K.; Landsman, H.; Leich, H.; Leier, D.; Leuthold, M.; Liubarsky,
I.; Lundberg, J.; Lünemann, J.; Madsen, J.; Mase, K.; Matis, H. S.;
McCauley, T.; McParland, C. P.; Meli, A.; Messarius, T.; Mészáros,
P.; Miyamoto, H.; Mokhtarani, A.; Montaruli, T.; Morey, A.; Morse,
R.; Movit, S. M.; Münich, K.; Nahnhauer, R.; Nam, J. W.; Nießen,
P.; Nygren, D. R.; Ögelman, H.; Olivas, A.; Patton, S.; Peña-Garay,
C.; Pérez de Los Heros, C.; Piegsa, A.; Pieloth, D.; Pohl, A. C.;
Porrata, R.; Pretz, J.; Price, P. B.; Przybylski, G. T.; Rawlins, K.;
Razzaque, S.; Resconi, E.; Rhode, W.; Ribordy, M.; Rizzo, A.; Robbins,
S.; Roth, P.; Rott, C.; Rutledge, D.; Ryckbosch, D.; Sander, H. -G.;
Sarkar, S.; Schlenstedt, S.; Schmidt, T.; Schneider, D.; Seckel, D.;
Seo, S. H.; Seunarine, S.; Silvestri, A.; Smith, A. J.; Solarz, M.;
Song, C.; Sopher, J. E.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.;
Stanev, T.; Steffen, P.; Stezelberger, T.; Stokstad, R. G.; Stoufer,
M. C.; Stoyanov, S.; Strahler, E. A.; Straszheim, T.; Sulanke, K. -H.;
Sullivan, G. W.; Sumner, T. J.; Taboada, I.; Tarasova, O.; Tepe, A.;
Thollander, L.; Tilav, S.; Tluczykont, M.; Toale, P. A.; Turčan, D.;
van Eijndhoven, N.; Vandenbroucke, J.; van Overloop, A.; Voigt, B.;
Wagner, W.; Walck, C.; Waldmann, H.; Walter, M.; Wang, Y. -R.; Wendt,
C.; Wiebusch, C. H.; Wikström, G.; Williams, D. R.; Wischnewski,
R.; Wissing, H.; Woschnagg, K.; Xu, X. W.; Yodh, G.; Yoshida, S.;
Zornoza, J. D.
Bibcode: 2007PhRvD..75j2001A
Altcode: 2006astro.ph.11063A
We report the results of a five-year survey of the northern sky to
search for point sources of high energy neutrinos. The search was
performed on the data collected with the AMANDA-II neutrino telescope
in the years 2000 to 2004, with a live time of 1001 days. The sample
of selected events consists of 4282 upward going muon tracks with high
reconstruction quality and an energy larger than about 100 GeV. We found
no indication of point sources of neutrinos and set 90% confidence
level flux upper limits for an all-sky search and also for a catalog
of 32 selected sources. For the all-sky search, our average (over
declination and right ascension) experimentally observed upper limit
Φ0=((E)/(1TeV))γ·(dΦ)/(dE) to a point source
flux of muon and tau neutrino (detected as muons arising from taus) is
Φνμ+ν¯μ0+Φντ+ν¯τ0=11.1×10-11TeV-1cm-2s-1,
in the energy range between 1.6 TeV and 2.5 PeV for a flavor ratio
Φνμ+ν¯μ0/Φντ+ν¯τ0=1
and assuming a spectral index γ=2. It should be noticed
that this is the first time we set upper limits to the flux
of muon and tau neutrinos. In previous papers we provided
muon neutrino upper limits only neglecting the sensitivity
to a signal from tau neutrinos, which improves the limits
by 10% to 16%. The value of the average upper limit presented
in this work corresponds to twice the limit on the muon neutrino flux
Φνμ+ν¯μ0=5.5×10-11TeV-1cm-2s-1.
A stacking analysis for preselected active galactic nuclei and a search
based on the angular separation of the events were also performed. We
report the most stringent flux upper limits to date, including the
results of a detailed assessment of systematic uncertainties.
Title: VizieR Online Data Catalog: AGN neutrino source candidates
(Achterberg+, 2006)
Authors: Achterberg, A.; Ackermann, M.; Adams, J.; Ahrens, J.;
Atlee, D. W.; Bahcall, J. N.; Bair, X.; Baret, B.; Bartelt, M.;
Barwick, S. W.; Bay, R.; Beattie, K.; Becka, T.; Becker, J. K.;
Becker, K. -H.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand,
D.; Besson, D. Z.; Blaufuss, E.; Boersma, D. J.; Bohm, C.; Boeser,
S.; Botner, O.; Bouchta, A.; Braun, J.; Burgess, C.; Burgess, T.;
Castermans, T.; Chirkin, D.; Clem, J.; Collin, B.; Conrad, J.; Cooley,
J.; Cowen, D. F.; D'Agostino, M. V.; Davour, A.; Day, C. T.; de Clercq,
C.; Desiati, P.; De Young, T.; Dreyer, J.; Duvoort, M. R.; Edwards,
W. R.; Ehrlich, R.; Ellsworth, R. W.; Evenson, P. A.; Fazely, A. R.;
Feser, T.; Filimonov, K.; Gaisser, T. K.; Gallagher, J.; Ganugapati,
R.; Geenen, H.; Gerhardt, L.; Goldschmidt, A.; Goodman, J. A.; Greene,
M. G.; Grullon, S.; Gross, A.; Gunasingha, R. M.; Hallgren, A.; Halzen,
F.; Han, K.; Hanson, K.; Hardtke, D.; Hardtke, R.; Harenberg, T.; Hart,
J. E.; Hauschildt, T.; Hays, D.; Heise, J.; Helbing, K.; Hellwig,
M.; Herquet, P.; Hill, G. C.; Hodges, J.; Hoffman, K. D.; Hoshina,
K.; Hubert, D.; Hughey, B.; Hulth, P. O.; Hultqvist, K.; Hundertmark,
S.; Ishihara, A.; Jacobsen, J.; Japaridze, G. S.; Jones, A.; Joseph,
J. M.; Kampert, K. -H.; Karle, A.; Kawai, H.; Kelley, J. L.; Kestel,
M.; Kitamura, N.; Klein, S. R.; Klepser, S.; Kohnen, G.; Kolanoski, H.;
Koepke, L.; Krasberg, M.; Kuehn, K.; Landsman, H.; Lang, R.; Leich,
H.; Leuthold, M.; Liubarsky, I.; Lundbert, J.; Madsen, J.; Mase, K.;
Matis, H. S.; McCauley, T.; McParland, C. P.; Meli, A.; Messarius, T.;
Meszaros, P.; Minor, R. H.; Miocinovic, P.; Miyamoto, H.; Mokhtarani,
A.; Montaruli, T.; Morey, A.; Morse, R.; Movit, S. M.; Munich, K.;
Nahnhauer, R.; Nam, J. W.; Niessen, P.; Nygren, D. R.; Oegelman, H.;
Olbrechts, Ph.; Olivas, A.; Patton, S.; Pena-Garay, C.; Perez de los
Heros, C.; Pieloth, D.; Pohl, A. C.; Porrata, R.; Pretz, J.; Price,
P. B.; Przybylski, G. T.; Rawlins, K.; Razzaque, S.; Refflinghaus, F.;
Resconi, E.; Rhode, W.; Ribordy, M.; Richter, S.; Rizzo, A.; Robbins,
S.; Rott, C.; Rutledge, D.; Sander, H. -G.; Schlenstedt, S.; Schneider,
D.; Seckel, D.; Seo, S. H.; Seunarine, S.; Silvestri, A.; Smith, A. J.;
Solarz, M.; Song, C.; Sopher, J. E.; Spiczak, G. M.; Spiering, C.;
Stamatikos, M.; Stanev, T.; Steffen, P.; Steele, D.; Stezelberger,
T.; Stokstad, R. G.; Stoufer, M. C.; Stoyanov, S.; Sulanke, K. -H.;
Sullivan, G. W.; Sumner, T. J.; Taboada, I.; Tarasova, O.; Tepe, A.;
Thollander, L.; Tilav, S.; Toale, P. A.; Turcan, D.; Van Eijndhoven,
T. J.; Vandenbroucke, J.; Voigt, B.; Wagner, W.; Walck, C.; Waldmann,
H.; Walter, M.; Wang, Y. -R.; Wendt, C.; Wiesbusch, C. H.; Wikstroem,
G.; Williams, D. R.; Wischnewski, R.; Wissing, H.; Woschnagg, K.;
Xu, X. W.; Yodh, G.; Yoshida, S.; Zornoza, J. D.; Biermann, P. L.
Bibcode: 2007yCatp030002601A
Altcode:
The sensitivity of a search for sources of TeV neutrinos can be
improved by grouping potential sources together into generic classes
in a procedure that is known as source stacking. In this paper,
we define catalogs of Active Galactic Nuclei (AGN) and use them to
perform a source stacking analysis. The grouping of AGN into classes is
done in two steps: first, AGN classes are defined, then, sources to be
stacked are selected assuming that a potential neutrino flux is linearly
correlated with the photon luminosity in a certain energy band (radio,
IR, optical, keV, GeV, TeV). Lacking any secure detailed knowledge on
neutrino production in AGN, this correlation is motivated by hadronic
AGN models, as briefly reviewed in this paper. The source stacking
search for neutrinos from generic AGN classes is illustrated using the
data collected by the AMANDA-II high-energy neutrino detector during
the year 2000. No significant excess for any of the suggested groups
was found. (11 data files).
Title: Limits on the High-Energy Gamma and Neutrino Fluxes from
the SGR 1806-20 Giant Flare of 27 December 2004 with the AMANDA-II
Detector
Authors: Achterberg, A.; Ackermann, M.; Adams, J.; Ahrens, J.; Andeen,
K.; Atlee, D. W.; Bahcall, J. N.; Bai, X.; Baret, B.; Bartelt, M.;
Barwick, S. W.; Bay, R.; Beattie, K.; Becka, T.; Becker, J. K.;
Becker, K. -H.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand,
D.; Besson, D. Z.; Blaufuss, E.; Boersma, D. J.; Bohm, C.; Bolmont, J.;
Böser, S.; Botner, O.; Bouchta, A.; Braun, J.; Burgess, C.; Burgess,
T.; Castermans, T.; Chirkin, D.; Christy, B.; Clem, J.; Cowen, D. F.;
D'Agostino, M. V.; Davour, A.; Day, C. T.; de Clercq, C.; Demirörs,
L.; Descamps, F.; Desiati, P.; De Young, T.; Diaz-Velez, J. C.; Dreyer,
J.; Dumm, J. P.; Duvoort, M. R.; Edwards, W. R.; Ehrlich, R.; Eisch,
J.; Ellsworth, R. W.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.;
Feser, T.; Filimonov, K.; Fox, B. D.; Gaisser, T. K.; Gallagher, J.;
Ganugapati, R.; Geenen, H.; Gerhardt, L.; Goldschmidt, A.; Goodman,
J. A.; Gozzini, R.; Grullon, S.; Groß, A.; Gunasingha, R. M.;
Gurtner, M.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Hardtke,
D.; Hardtke, R.; Harenberg, T.; Hart, J. E.; Hauschildt, T.; Hays, D.;
Heise, J.; Helbing, K.; Hellwig, M.; Herquet, P.; Hill, G. C.; Hodges,
J.; Hoffman, K. D.; Hommez, B.; Hoshina, K.; Hubert, D.; Hughey,
B.; Hulth, P. O.; Hultqvist, K.; Hundertmark, S.; Hülß, J. -P.;
Ishihara, A.; Jacobsen, J.; Japaridze, G. S.; Jones, A.; Joseph,
J. M.; Kampert, K. -H.; Karle, A.; Kawai, H.; Kelley, J. L.; Kestel,
M.; Kitamura, N.; Klein, S. R.; Klepser, S.; Kohnen, G.; Kolanoski,
H.; Köpke, L.; Krasberg, M.; Kuehn, K.; Landsman, H.; Leich, H.;
Liubarsky, I.; Lundberg, J.; Madsen, J.; Mase, K.; Matis, H. S.;
McCauley, T.; McParland, C. P.; Meli, A.; Messarius, T.; Mészáros,
P.; Miyamoto, H.; Mokhtarani, A.; Montaruli, T.; Morey, A.; Morse,
R.; Movit, S. M.; Münich, K.; Nahnhauer, R.; Nam, J. W.; Nießen,
P.; Nygren, D. R.; Ögelman, H.; Olbrechts, Ph.; Olivas, A.; Patton,
S.; Peña-Garay, C.; Pérez de Los Heros, C.; Piegsa, A.; Pieloth, D.;
Pohl, A. C.; Porrata, R.; Pretz, J.; Price, P. B.; Przybylski, G. T.;
Rawlins, K.; Razzaque, S.; Refflinghaus, F.; Resconi, E.; Rhode, W.;
Ribordy, M.; Rizzo, A.; Robbins, S.; Roth, P.; Rott, C.; Rutledge, D.;
Ryckbosch, D.; Sander, H. -G.; Sarkar, S.; Schlenstedt, S.; Schmidt,
T.; Schneider, D.; Seckel, D.; Seo, S. H.; Seunarine, S.; Silvestri,
A.; Smith, A. J.; Solarz, M.; Song, C.; Sopher, J. E.; Spiczak, G. M.;
Spiering, C.; Stamatikos, M.; Stanev, T.; Steffen, P.; Stezelberger,
T.; Stokstad, R. G.; Stoufer, M. C.; Stoyanov, S.; Strahler, E. A.;
Straszheim, T.; Sulanke, K. -H.; Sullivan, G. W.; Sumner, T. J.;
Taboada, I.; Tarasova, O.; Tepe, A.; Thollander, L.; Tilav, S.;
Toale, P. A.; Turčan, D.; van Eijndhoven, N.; Vandenbroucke, J.;
van Overloop, A.; Voigt, B.; Wagner, W.; Walck, C.; Waldmann, H.;
Walter, M.; Wang, Y. -R.; Wendt, C.; Wiebusch, C. H.; Wikström, G.;
Williams, D. R.; Wischnewski, R.; Wissing, H.; Woschnagg, K.; Xu,
X. W.; Yodh, G.; Yoshida, S.; Zornoza, J. D.
Bibcode: 2006PhRvL..97v1101A
Altcode: 2006astro.ph..7233T
On 27 December 2004, a giant γ flare from the Soft Gamma-Ray Repeater
1806-20 saturated many satellite gamma-ray detectors, being the
brightest transient event ever observed in the Galaxy. AMANDA-II was
used to search for down-going muons indicative of high-energy gammas
and/or neutrinos from this object. The data revealed no significant
signal, so upper limits (at 90% C.L.) on the normalization constant
were set: 0.05(0.5)TeV-1m-2s-1
for γ=-1.47 (-2) in the gamma flux and
0.4(6.1)TeV-1m-2s-1 for γ=-1.47 (-2)
in the high-energy neutrino flux.
Title: On the selection of AGN neutrino source candidates for a
source stacking analysis with neutrino telescopes
Authors: Achterberg, A.; Ackermann, M.; Adams, J.; Ahrens, J.;
Atlee, D. W.; Bahcall, J. N.; Bai, X.; Baret, B.; Bartelt, M.;
Barwick, S. W.; Bay, R.; Beattie, K.; Becka, T.; Becker, J. K.;
Becker, K. -H.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand,
D.; Besson, D. Z.; Blaufuss, E.; Boersma, D. J.; Bohm, C.; Böser,
S.; Botner, O.; Bouchta, A.; Braun, J.; Burgess, C.; Burgess, T.;
Castermans, T.; Chirkin, D.; Clem, J.; Collin, B.; Conrad, J.; Cooley,
J.; Cowen, D. F.; D'Agostino, M. V.; Davour, A.; Day, C. T.; de Clercq,
C.; Desiati, P.; De Young, T.; Dreyer, J.; Duvoort, M. R.; Edwards,
W. R.; Ehrlich, R.; Ellsworth, R. W.; Evenson, P. A.; Fazely, A. R.;
Feser, T.; Filimonov, K.; Gaisser, T. K.; Gallagher, J.; Ganugapati,
R.; Geenen, H.; Gerhardt, L.; Goldschmidt, A.; Goodman, J. A.; Greene,
M. G.; Grullon, S.; Groß, A.; Gunasingha, R. M.; Hallgren, A.; Halzen,
F.; Han, K.; Hanson, K.; Hardtke, D.; Hardtke, R.; Harenberg, T.; Hart,
J. E.; Hauschildt, T.; Hays, D.; Heise, J.; Helbing, K.; Hellwig,
M.; Herquet, P.; Hill, G. C.; Hodges, J.; Hoffman, K. D.; Hoshina,
K.; Hubert, D.; Hughey, B.; Hulth, P. O.; Hultqvist, K.; Hundertmark,
S.; Ishihara, A.; Jacobsen, J.; Japaridze, G. S.; Jones, A.; Joseph,
J. M.; Kampert, K. -H.; Karle, A.; Kawai, H.; Kelley, J. L.; Kestel,
M.; Kitamura, N.; Klein, S. R.; Klepser, S.; Kohnen, G.; Kolanoski, H.;
Köpke, L.; Krasberg, M.; Kuehn, K.; Landsman, H.; Lang, R.; Leich,
H.; Leuthold, M.; Liubarsky, I.; Lundberg, J.; Madsen, J.; Mase, K.;
Matis, H. S.; McCauley, T.; McParland, C. P.; Meli, A.; Messarius,
T.; Mészáros, P.; Minor, R. H.; Miočinović, P.; Miyamoto, H.;
Mokhtarani, A.; Montaruli, T.; Morey, A.; Morse, R.; Movit, S. M.;
Münich, K.; Nahnhauer, R.; Nam, J. W.; Nießen, P.; Nygren, D. R.;
Ögelman, H.; Olbrechts, Ph.; Olivas, A.; Patton, S.; Peña-Garay,
C.; Pérez de Los Heros, C.; Pieloth, D.; Pohl, A. C.; Porrata, R.;
Pretz, J.; Price, P. B.; Przybylski, G. T.; Rawlins, K.; Razzaque,
S.; Refflinghaus, F.; Resconi, E.; Rhode, W.; Ribordy, M.; Richter,
S.; Rizzo, A.; Robbins, S.; Rott, C.; Rutledge, D.; Sander, H. -G.;
Schlenstedt, S.; Schneider, D.; Seckel, D.; Seo, S. H.; Seunarine,
S.; Silvestri, A.; Smith, A. J.; Solarz, M.; Song, C.; Sopher,
J. E.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.;
Steffen, P.; Steele, D.; Stezelberger, T.; Stokstad, R. G.; Stoufer,
M. C.; Stoyanov, S.; Sulanke, K. -H.; Sullivan, G. W.; Sumner, T. J.;
Taboada, I.; Tarasova, O.; Tepe, A.; Thollander, L.; Tilav, S.; Toale,
P. A.; Turčan, D.; van Eijndhoven, N.; Vandenbroucke, J.; Voigt, B.;
Wagner, W.; Walck, C.; Waldmann, H.; Walter, M.; Wang, Y. -R.; Wendt,
C.; Wiebusch, C. H.; Wikström, G.; Williams, D. R.; Wischnewski,
R.; Wissing, H.; Woschnagg, K.; Xu, X. W.; Yodh, G.; Yoshida, S.;
Zornoza, J. D.; Biermann, P. L.
Bibcode: 2006APh....26..282A
Altcode: 2006astro.ph..9534A
The sensitivity of a search for sources of TeV neutrinos can be
improved by grouping potential sources together into generic classes
in a procedure that is known as source stacking. In this paper,
we define catalogs of Active Galactic Nuclei (AGN) and use them to
perform a source stacking analysis. The grouping of AGN into classes is
done in two steps: first, AGN classes are defined, then, sources to be
stacked are selected assuming that a potential neutrino flux is linearly
correlated with the photon luminosity in a certain energy band (radio,
IR, optical, keV, GeV, TeV). Lacking any secure detailed knowledge on
neutrino production in AGN, this correlation is motivated by hadronic
AGN models, as briefly reviewed in this paper. The source stacking
search for neutrinos from generic AGN classes is illustrated using the
data collected by the AMANDA-II high-energy neutrino detector during
the year 2000. No significant excess for any of the suggested groups
was found.
Title: First year performance of the IceCube neutrino telescope
Authors: IceCube Collaboration; Achterberg, A.; Ackermann, M.; Adams,
J.; Ahrens, J.; Andeen, K.; Atlee, D. W.; Baccus, J.; Bahcall, J. N.;
Bai, X.; Baret, B.; Bartelt, M.; Barwick, S. W.; Bay, R.; Beattie, K.;
Becka, T.; Becker, J. K.; Becker, K. -H.; Berghaus, P.; Berley, D.;
Bernardini, E.; Bertrand, D.; Besson, D. Z.; Blaufuss, E.; Boersma,
D. J.; Bohm, C.; Böser, S.; Botner, O.; Bouchta, A.; Braun, J.;
Burgess, C.; Burgess, T.; Castermans, T.; Cherwinka, J.; Chirkin, D.;
Clem, J.; Cowen, D. F.; D'Agostino, M. V.; Davour, A.; Day, C. T.;
de Clercq, C.; Demirörs, L.; Desiati, P.; De Young, T.; Diaz-Velez,
J. C.; Dreyer, J.; Duvoort, M. R.; Edwards, W. R.; Ehrlich, R.; Eisch,
J.; Elcheikh, A.; Ellsworth, R. W.; Evenson, P. A.; Fadiran, O.;
Fazely, A. R.; Feser, T.; Filimonov, K.; Fox, B. D.; Gaisser, T. K.;
Gallagher, J.; Ganugapati, R.; Geenen, H.; Gerhardt, L.; Goldschmidt,
A.; Goodman, J. A.; Gozzini, R.; Greene, M. G.; Grullon, S.; Groß,
A.; Gunasingha, R. M.; Gurtner, M.; Hallgren, A.; Halzen, F.; Han,
K.; Hanson, K.; Hardtke, D.; Hardtke, R.; Harenberg, T.; Hart, J. E.;
Haugen, J.; Hauschildt, T.; Hays, D.; Heise, J.; Helbing, K.; Hellwig,
M.; Herquet, P.; Hill, G. C.; Hodges, J.; Hoffman, K. D.; Hoshina, K.;
Hubert, D.; Hughey, B.; Hulth, P. O.; Hultqvist, K.; Hundertmark, S.;
Hülß, J. -P.; Ishihara, A.; Jacobsen, J.; Japaridze, G. S.; Jones,
A.; Joseph, J. M.; Kampert, K. -H.; Karle, A.; Kawai, H.; Kelley,
J. L.; Kestel, M.; Kitamura, N.; Klein, S. R.; Klepser, S.; Kohnen,
G.; Kolanoski, H.; Köpke, L.; Krasberg, M.; Kuehn, K.; Landsman, H.;
Laundrie, A.; Leich, H.; Liubarsky, I.; Lundberg, J.; MacKenzie, C.;
Madsen, J.; Mase, K.; Matis, H. S.; McCauley, T.; McParland, C. P.;
Meli, A.; Messarius, T.; Mészáros, P.; Miyamoto, H.; Mokhtarani,
A.; Montaruli, T.; Morey, A.; Morse, R.; Movit, S. M.; Münich, K.;
Muratas, A.; Nahnhauer, R.; Nam, J. W.; Nießen, P.; Nygren, D. R.;
Ögelman, H.; Olbrechts, Ph.; Olivas, A.; Patton, S.; Peña-Garay,
C.; Pérez de Los Heros, C.; Pettersen, C.; Piegsa, A.; Pieloth, D.;
Pohl, A. C.; Porrata, R.; Pretz, J.; Price, P. B.; Przybylski, G. T.;
Rawlins, K.; Razzaque, S.; Refflinghaus, F.; Resconi, E.; Rhode, W.;
Ribordy, M.; Rizzo, A.; Robbins, S.; Rott, C.; Rutledge, D.; Sander,
H. -G.; Sandstrom, P.; Sarkar, S.; Schlenstedt, S.; Schneider, D.;
Seckel, D.; Seo, S. H.; Seunarine, S.; Silvestri, A.; Smith, A. J.;
Solarz, M.; Song, C.; Sopher, J. E.; Spiczak, G. M.; Spiering, C.;
Stamatikos, M.; Stanev, T.; Steffen, P.; Stezelberger, T.; Stokstad,
R. G.; Stoufer, M. C.; Stoyanov, S.; Strahler, E. A.; Sulanke, K. -H.;
Sullivan, G. W.; Taboada, I.; Tarasova, O.; Tepe, A.; Thollander,
L.; Tilav, S.; Toale, P. A.; Turčan, D.; van Eijndhoven, N.;
Vandenbroucke, J.; van Overloop, A.; Voigt, B.; Wagner, W.; Walck,
C.; Waldmann, H.; Walter, M.; Wang, Y. -R.; Wendt, C.; Whitney, M.;
Wiebusch, C. H.; Wikström, G.; Williams, D. R.; Wischnewski, R.;
Wisniewski, P.; Wissing, H.; Woschnagg, K.; Xu, X. W.; Yodh, G.;
Yoshida, S.; Zornoza, J. D.
Bibcode: 2006APh....26..155I
Altcode: 2006astro.ph..4450T
The first sensors of the IceCube neutrino observatory were deployed at
the South Pole during the austral summer of 2004 2005 and have been
producing data since February 2005. One string of 60 sensors buried
in the ice and a surface array of eight ice Cherenkov tanks took data
until December 2005 when deployment of the next set of strings and tanks
began. We have analyzed these data, demonstrating that the performance
of the system meets or exceeds design requirements. Times are determined
across the whole array to a relative precision of better than 3 ns,
allowing reconstruction of muon tracks and light bursts in the ice,
of air-showers in the surface array and of events seen in coincidence
by surface and deep-ice detectors separated by up to 2.5 km.
Title: Limits on the muon flux from neutralino annihilations at the
center of the Earth with AMANDA
Authors: Achterberg, A.; Ackermann, M.; Adams, J.; Ahrens, J.; Andeen,
K.; Atlee, D. W.; Bahcall, J. N.; Bai, X.; Baret, B.; Bartelt, M.;
Barwick, S. W.; Bay, R.; Beattie, K.; Becka, T.; Becker, J. K.;
Becker, K. -H.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand,
D.; Besson, D. Z.; Blaufuss, E.; Boersma, D. J.; Bohm, C.; Böser,
S.; Botner, O.; Bouchta, A.; Bouhali, O.; Braun, J.; Burgess,
C.; Burgess, T.; Castermans, T.; Chirkin, D.; Clem, J.; Conrad,
J.; Cooley, J.; Cowen, D. F.; D'Agostino, M. V.; Davour, A.; Day,
C. T.; de Clercq, C.; Desiati, P.; De Young, T.; Diaz-Velez, J. C.;
Dreyer, J.; Duvoort, M. R.; Edwards, W. R.; Ehrlich, R.; Ekström,
P.; Ellsworth, R. W.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.;
Feser, T.; Filimonov, K.; Gaisser, T. K.; Gallagher, J.; Ganugapati,
R.; Geenen, H.; Gerhardt, L.; Goldschmidt, A.; Goodman, J. A.;
Gozzini, R.; Greene, M. G.; Grullon, S.; Groß, A.; Gunasingha,
R. M.; Gurtner, M.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.;
Hardtke, D.; Hardtke, R.; Harenberg, T.; Hart, J. E.; Hauschildt,
T.; Hays, D.; Heise, J.; Helbing, K.; Hellwig, M.; Herquet, P.; Hill,
G. C.; Hodges, J.; Hoffman, K. D.; Hoshina, K.; Hubert, D.; Hughey,
B.; Hulth, P. O.; Hultqvist, K.; Hundertmark, S.; Hülß, J. -P.;
Ishihara, A.; Jacobsen, J.; Japaridze, G. S.; Jones, A.; Joseph,
J. M.; Kampert, K. -H.; Karle, A.; Kawai, H.; Kelley, J. L.; Kestel,
M.; Klein, S. R.; Klepser, S.; Kohnen, G.; Kolanoski, H.; Köpke,
L.; Krasberg, M.; Kuehn, K.; Landsman, H.; Leich, H.; Leuthold, M.;
Liubarsky, I.; Lundberg, J.; Madsen, J.; Marciniewski, P.; Mase, K.;
Matis, H. S.; McCauley, T.; McParland, C. P.; Meli, A.; Messarius,
T.; Mészáros, P.; Minaeva, Y.; Miočinović, P.; Miyamoto, H.;
Mokhtarani, A.; Montaruli, T.; Morey, A.; Morse, R.; Movit, S. M.;
Münich, K.; Nahnhauer, R.; Nam, J. W.; Neunhöffer, T.; Nießen, P.;
Nygren, D. R.; Ögelman, H.; Olbrechts, Ph.; Olivas, A.; Patton, S.;
Peña-Garay, C.; Pérez de Los Heros, C.; Piegsa, A.; Pieloth, D.;
Pohl, A. C.; Porrata, R.; Pretz, J.; Price, P. B.; Przybylski, G. T.;
Rawlins, K.; Razzaque, S.; Refflinghaus, F.; Resconi, E.; Rhode, W.;
Ribordy, M.; Rizzo, A.; Robbins, S.; RodríGuez Martino, J.; Rott,
C.; Rutledge, D.; Sander, H. -G.; Schlenstedt, S.; Schneider, D.;
Schwarz, R.; Seckel, D.; Seo, S. H.; Seunarine, S.; Silvestri, A.;
Smith, A. J.; Solarz, M.; Song, C.; Sopher, J. E.; Spiczak, G. M.;
Spiering, C.; Stamatikos, M.; Stanev, T.; Steffen, P.; Stezelberger,
T.; Stokstad, R. G.; Stoufer, M. C.; Stoyanov, S.; Strahler, E. A.;
Sulanke, K. -H.; Sullivan, G. W.; Sumner, T. J.; Taboada, I.; Tarasova,
O.; Tepe, A.; Thollander, L.; Tilav, S.; Toale, P. A.; Turčan, D.;
van Eijndhoven, N.; Vandenbroucke, J.; Voigt, B.; Wagner, W.; Walck,
C.; Waldmann, H.; Walter, M.; Wang, Y. -R.; Wendt, C.; Wiebusch,
C. H.; Wikström, G.; Williams, D. R.; Wischnewski, R.; Wissing, H.;
Woschnagg, K.; Xu, X. W.; Yodh, G.; Yoshida, S.; Zornoza, J. D.
Bibcode: 2006APh....26..129A
Altcode:
A search has been performed for nearly vertically upgoing
neutrino-induced muons with the Antarctic Muon And Neutrino Detector
Array (AMANDA), using data taken over the three year period 1997-99. No
excess above the expected atmospheric neutrino background has been
found. Upper limits at 90% confidence level have been set on the
annihilation rate of neutralinos at the center of the Earth, as well
as on the muon flux at AMANDA induced by neutrinos created by the
annihilation products.
Title: 10,000 Standard Solar Models: A Monte Carlo Simulation
Authors: Bahcall, John N.; Serenelli, Aldo M.; Basu, Sarbani
Bibcode: 2006ApJS..165..400B
Altcode: 2005astro.ph.11337B
We have evolved 10,000 solar models using 21 input parameters that are
randomly drawn for each model from separate probability distributions
for every parameter. We use the results of these models to determine the
theoretical uncertainties in the predicted surface helium abundance,
the profile of the sound speed versus radius, the profile of the
density versus radius, the depth of the solar convective zone, the
eight principal solar neutrino fluxes, and the fractions of nuclear
reactions that occur in the CNO cycle or in the three branches of
the p-p chains. We also determine the correlation coefficients of the
neutrino fluxes for use in analysis of solar neutrino oscillations. Our
calculations include the most accurate available input parameters,
including radiative opacity, equation of state, and nuclear cross
sections. We incorporate both the recently determined heavy element
abundances recommended by Asplund et al. and the older (higher) heavy
element abundances recommended by Grevesse & Sauval. We present
best estimates of many characteristics of the standard solar model
for both sets of recommended heavy element compositions.
Title: A Survey of z>5.7 Quasars in the Sloan Digital Sky
Survey. IV. Discovery of Seven Additional Quasars
Authors: Fan, Xiaohui; Strauss, Michael A.; Richards, Gordon
T.; Hennawi, Joseph F.; Becker, Robert H.; White, Richard L.;
Diamond-Stanic, Aleksandar M.; Donley, Jennifer L.; Jiang, Linhua; Kim,
J. Serena; Vestergaard, Marianne; Young, Jason E.; Gunn, James E.;
Lupton, Robert H.; Knapp, Gillian R.; Schneider, Donald P.; Brandt,
W. N.; Bahcall, Neta A.; Barentine, J. C.; Brinkmann, J.; Brewington,
Howard J.; Fukugita, Masataka; Harvanek, Michael; Kleinman, S. J.;
Krzesinski, Jurek; Long, Dan; Neilsen, Eric H., Jr.; Nitta, Atsuko;
Snedden, Stephanie A.; Voges, Wolfgang
Bibcode: 2006AJ....131.1203F
Altcode: 2005astro.ph.12080F
We present the discovery of seven quasars at z>5.7, selected
from ~2000 deg2 of multicolor imaging data of the Sloan
Digital Sky Survey. The new quasars have redshifts z from 5.79 to
6.13. Five are selected as part of a complete flux-limited sample in
the SDSS northern Galactic cap; two have larger photometric errors
and are not part of the complete sample. One of the new quasars, SDSS
J1335+3533 (z=5.93), exhibits no emission lines; the 3 σ limit on the
rest-frame equivalent width of the Lyα+N V line is 5 Å. It is the
highest redshift lineless quasar known and could be a gravitational
lensed galaxy, a BL Lac object, or a new type of quasar. Two new z>6
quasars, SDSS 1250+3130 (z=6.13) and SDSS J1137+3549 (z=6.01), show deep
Gunn-Peterson absorption gaps in Lyα. These gaps are narrower than
the complete Gunn-Peterson absorption troughs observed among quasars
at z>6.2 and do not have complete Lyβ absorption. Based on
observations obtained with the Sloan Digital Sky Survey; the Apache
Point Observatory's 3.5 m telescope, which is owned and operated by
the Astrophysical Research Consortium; the MMT Observatory, a joint
facility of the University of Arizona and the Smithsonian Institution;
the University of Arizona's 2.3 m Bok Telescope; the Kitt Peak National
Observatory's 4 m Mayall Telescope; the 6.5 m Walter Baade Telescope at
the Las Campanas Observatory, a collaboration between the Observatories
of the Carnegie Institution of Washington, the University of Arizona,
Harvard University, the University of Michigan, and the Massachusetts
Institute of Technology; and the W. M. Keck Observatory, which is
operated as a scientific partnership among the California Institute of
Technology, the University of California, and the National Aeronautics
and Space Administration, and made possible by the generous financial
support of the W. M. Keck Foundation. This paper is dedicated to
the memory of John N. Bahcall.
Title: Stellar Energy Generation and Solar Neutrinos
Authors: Bahcall, John N.; Salpeter, Edwin E.
Bibcode: 2006hbp..book..147B
Altcode:
No abstract at ADS
Title: What Is the Neon Abundance of the Sun?
Authors: Bahcall, John N.; Basu, Sarbani; Serenelli, Aldo M.
Bibcode: 2005ApJ...631.1281B
Altcode: 2005astro.ph..2563B
We have evolved a series of 13 complete solar models that utilize
different assumed heavy-element compositions. Models that are
based upon the heavy-element abundances recently determined by
Asplund and coworkers are inconsistent with helioseismological
measurements. However, models in which the neon abundance is
increased by 0.4-0.5 dex to logN(Ne)=8.29+/-0.05 [on the scale in which
logN(H)=12] are consistent with the helioseismological measurements even
though the other heavy-element abundances are in agreement with the
determinations of Asplund et al. These results sharpen and strengthen
an earlier study by Antia & Basu. The predicted solar neutrino
fluxes are affected by the uncertainties in the composition by less
than their 1 σ theoretical uncertainties.
Title: Mapping Globular Cluster Tidal Streams
Authors: Grillmair, Carl J.; Dionatos, Odysseas; Bahcall, John;
Cutri, Roc; Geisler, Douglas; Gieren, Wolfgang; Grebel, Eva; Johnston,
Kathryn; Majewski, Steven; Patterson, Richard; Reid, Neill; Spergel,
David; Tremaine, Scott
Bibcode: 2005noao.prop..111G
Altcode:
The primary scientific goal of this program is to detect and map
the tidal streams emanating from halo globular clusters. We propose
to obtain moderately deep V and I imaging of the regions within 2°
of the centers of five globular clusters with R_sun < 50 kpc and
with a high probability of having strong tidal tails. Given that
these cold tidal streams are on essentially the same orbits as their
parent clusters, they can be used to constrain both the formation and
evolution of the Galactic halo as well as the present shape of the
Galactic potential field. With follow-up spectroscopy to eliminate
foreground contaminants, the stars in these tidal streams will be used
to construct a high-priority target list for the Space Interferometry
Mission (SIM). Proper motion measurements of these stars with SIM will
enable us to tightly constrain the detailed, three-dimensional structure
of the Galactic potential field from the Solar Circle out to 50 kpc.
Title: How Do Uncertainties in the Surface Chemical Composition of
the Sun Affect the Predicted Solar Neutrino Fluxes?
Authors: Bahcall, John N.; Serenelli, Aldo M.
Bibcode: 2005ApJ...626..530B
Altcode: 2004astro.ph.12096B
We show that uncertainties in the values of the surface heavy-element
abundances of the Sun are the largest source of the theoretical
uncertainty in calculating the p-p, pep, 8B, 13N,
15O, and 17F solar neutrino fluxes. Our results
focus attention on the necessity of improving the measurement of
heavy-element abundances, while at the same time reducing the estimated
uncertainties in the predicted solar neutrino fluxes due to abundance
errors. We evaluate for the first time the sensitivity (partial
derivative) of each solar neutrino flux with respect to the surface
abundance of each element. We then calculate the uncertainties in each
neutrino flux using the preferred ``conservative'' (based on changes of
measured values with time) and ``optimistic'' (current values) estimates
for the uncertainties in the element abundances. The total conservative
(optimistic) composition uncertainty in the predicted 8B
neutrino flux is 11.6% (5.0%) when sensitivities to individual element
abundances are used. The traditional method that lumps all abundances
into a single quantity (total heavy element-to-hydrogen ratio, Z/X)
yields a larger uncertainty, 20%. The uncertainties in the carbon,
oxygen, neon, silicon, sulphur, and iron abundances all make significant
contributions to the uncertainties in calculating solar neutrino
fluxes; the uncertainties of different elements are most important for
different neutrino fluxes. The uncertainty in the iron abundance is
the largest source of the estimated composition uncertainties of the
important 7Be and 8B solar neutrinos. Carbon
is the largest contributor to the uncertainty in the calculation of
the p-p, 13N, and 15O neutrino fluxes. However,
for all neutrino fluxes, several elements contribute comparable amounts
to the total composition uncertainty.
Title: Probing Galactic Dark Matter With SIM Observations of Tidal
Tails
Authors: Majewski, S. R.; Bahcall, J. N.; Geisler, D.; Gieren,
W.; Grebel, E. K.; Grillmair, C. J.; Johnston, K. V.; Law, D. R.;
Patterson, R. J.; Polak, A. A.; Reid, I. N.; Spergel, D. N.; Sumi,
T.; Tremaine, S.
Bibcode: 2005AAS...206.1413M
Altcode: 2005BAAS...37..454M
The nature of the dark matter that composes 90 Galaxy remains a profound
mystery. Astronomical observations can provide crucial insight on this
fundamental issue by probing the large-scale spatial distribution of
dark matter, addressing, in particular, the following questions: Is dark
matter in our Galaxy centrally concentrated and lumpy as predicted for
cold dark matter (such as the lightest SUSY particles or axions) or is
it more smoothly distributed and less lumpy? Is the overall shape of
the dark matter halo oblate (Johnston, Law & Majewski 2005, ApJ,
619, 800), prolate (Helmi 2004, ApJ, 610, L97) or triaxial (Newberg
& Yanny 2004, AAS, 205, 142.04)? What is the total mass and extent
of the Milky Way, and what is its corresponding role in the dynamics
of the Local Group? We intend to tackle these questions directly,
through observations of stars in objects whose dynamics reflect the
large-scale Galactic potential: satellite galaxies, star clusters,
and halo tidal streams. Measuring the motions of dynamical tracers
in the outer Galaxy demands proper motions accurate to better than
10 microarcsecond yr-1 at magnitudes V > 18. NASA's SIM
PlanetQuest is the only currently planned mission that can provide such
data. SIM observations of the well-mapped Sagittarius star stream will,
in addition, provide a definitive determination of the rotation speed
of the Sun, pinning down the scale of the Galactic rotation curve to
constrain the mass distribution in the inner Milky Way. Funded
by NASA/JPL contract 1228235 for the Taking Measure of the Milky Way
Key Project for SIM PlanetQuest.
Title: New Solar Opacities, Abundances, Helioseismology, and
Neutrino Fluxes
Authors: Bahcall, John N.; Serenelli, Aldo M.; Basu, Sarbani
Bibcode: 2005ApJ...621L..85B
Altcode: 2004astro.ph.12440B
We construct solar models with the newly calculated radiative
opacities from the Opacity Project (OP) and with recently determined
(lower) heavy-element abundances. We compare the results from the
new models with the predictions of a series of models that use OPAL
radiative opacities, older determinations of the surface heavy-element
abundances, and refinements of nuclear reaction rates. For all the
variations we consider, solar models that are constructed with the
newer and lower heavy-element abundances advocated by Asplund et
al. disagree by much more than the estimated measuring errors with the
helioseismological determinations of the depth of the solar convective
zone, the surface helium composition, the internal sound speeds, and
the density profile. Using the new OP radiative opacities, the ratio of
the 8B neutrino flux calculated with the older and larger
heavy-element abundances (or with the newer and lower heavy-element
abundances) to the total neutrino flux measured by the Sudbury Neutrino
Observatory is 1.09 (0.87) with a 9% experimental uncertainty and a 16%
theoretical uncertainty, 1σ errors.
Title: Neutrino Astronomy and Cosmic Rays at the South Pole:. Latest
Results from AMANDA and Perspectives for Icecube
Authors: Desiati, Paolo; Achterberg, A.; Ackermann, M.; Ahrens, J.;
Albrecht, H.; Atlee, D. W.; Bahcall, J. N.; Bai, X.; Bartelt, M.; Bay,
R.; Barwick, S. W.; Becka, T.; Becker, K. H.; Becker, J. K.; Berghaus,
P.; Bergmans, J.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson,
D. Z.; Blaufuss, E.; Boersma, D. J.; Bohm, C.; Böser, S.; Botner,
O.; Bouchta, A.; Bouhali, O.; Braun, J.; Burgess, C.; Burgess, T.;
Carithers, W.; Castermans, T.; Cavin, J.; Chinowsky, W.; Chirkin, D.;
Clem, J.; Coarasa, J. A.; Collin, B.; Conrad, J.; Cooley, J.; Cowen,
D. F.; Davour, A.; Day, C. T.; de Clercq, C.; De Young, T.; Edwards,
W. R.; Ehrlich, R.; Ekström, P.; Ellsworth, R. W.; Evenson, P. A.;
Fazely, A. R.; Feser, T.; Gaisser, T. K.; Gallagher, J.; Ganugapati,
R.; Geenen, H.; Gerhardt, L.; Goldschmidt, A.; Gross, A.; Gunasingha,
R. M.; Hallgren, A.; Halzen, F.; Hanson, K.; Hardtke, D.; Hardtke,
R.; Harenberg, T.; Hauschildt, T.; Hays, D.; Helbing, K.; Hellwig,
M.; Herquet, P.; Hill, G. C.; Hodges, J.; Hoshina, K.; Hubert, D.;
Hughey, B.; Hulth, P. O.; Hultqvist, K.; Hundertmark, S.; Jacobsen,
J.; Japaridze, G. S.; Jones, A.; Joseph, J. M.; Kampert, K. H.;
Karle, A.; Kawai, H.; Kelley, J.; Kestel, M.; Kitamura, N.; Klein,
S. R.; Koch, R.; Kohnen, G.; Köpke, L.; Kowalski, M.; Krasberg,
M.; Kuehn, K.; Kujawski, E.; Langer, N.; Leich, H.; Leuthold, M.;
Liubarsky, I.; Lundberg, J.; Madsen, J.; Mandli, K.; Marciniewski,
P.; Matis, H. S.; McParland, C. P.; Messarius, T.; Mészáros, P.;
Minaeva, Y.; Minor, R. H.; Miočinović, P.; Miyamoto, H.; Morse, R.;
Münich, K.; Nahnhauer, R.; Nam, J. W.; Neunhöffer, T.; Niessen, P.;
Nygren, D. R.; Ögelman, H.; Olbrechts, Ph.; Patton, S.; Paulos, R.;
Peña-Garay, C.; Pérez de Los Heros, C.; Pohl, A. C.; Porrata, R.;
Pretz, J.; Price, P. B.; Przybylski, G. T.; Rawlins, K.; Razzaque, S.;
Resconi, E.; Rhode, W.; Ribordy, M.; Richter, S.; Rodríguez Martino,
J.; Sander, H. G.; Schinarakis, K.; Schlenstedt, S.; Schneider, D.;
Schwarz, R.; Seckel, D.; Seo, S. H.; Silvestri, A.; Smith, A. J.;
Solarz, M.; Sopher, J. E.; Spiczak, G. M.; Spiering, C.; Stamatikos,
M.; Stanev, T.; Steele, D.; Steffen, P.; Stezelberger, T.; Stokstad,
R. G.; Stoyanov, S.; Straszheim, T. D.; Sulanke, K. H.; Sullivan,
G. W.; Sumner, T. J.; Taboada, I.; Tarasova, O.; Thollander, L.; Tilav,
S.; Turčan, D.; van Eijndhoven, N.; Vandenbroucke, J.; Voicu, L. C.;
Wagner, W.; Walck, C.; Walter, M.; Wang, Y. R.; Wiebusch, C. H.;
Wischnewski, R.; Wissing, H.; Woschnagg, K.; Yeck, J.; Yoshida, S.;
Yodh, G.
Bibcode: 2005IJMPA..20.6919D
Altcode:
The AMANDA neutrino telescope has been in operation at the South Pole
since 1996. The present final array configuration, operational since
2000, consists of 677 photomultiplier tubes arranged in 19 strings,
buried at depths between 1500 and 2000 m in the ice. The most recent
results on a multi-year search for point sources of neutrinos will
be shown. The study of events triggered in coincidence with the
surface array SPASE and AMANDA provided a result on cosmic ray
composition. Expected improvements from IceCube/IceTop will also
be discussed.
Title: Solar Models and Solar Neutrinos
Authors: Bahcall, J. N.
Bibcode: 2005PhST..121...46B
Altcode: 2004hep.ph...12068B
I provide a summary of the current theoretical knowledge of solar
neutrino fluxes as derived from precise solar models.
Title: Stellar Energy Generation and Solar Neutrinos
Authors: Bahcall, John N.; Salpeter, Edwin E.
Bibcode: 2005PhT....58j..44B
Altcode:
No abstract at ADS
Title: Helioseismological Implications of Recent Solar Abundance
Determinations
Authors: Bahcall, John N.; Basu, Sarbani; Pinsonneault, Marc;
Serenelli, Aldo M.
Bibcode: 2005ApJ...618.1049B
Altcode: 2004astro.ph..7060B
We show that standard solar models are in good agreement with the
helioseismologically determined sound speed and density as a function of
solar radius, the depth of the convective zone, and the surface helium
abundance, as long as those models do not incorporate the most recent
heavy-element abundance determinations. However, sophisticated new
analyses of the solar atmosphere infer lower abundances of the lighter
metals (like C, N, O, Ne, and Ar) than the previously widely used
surface abundances. We show that solar models that include the lower
heavy-element abundances disagree with the solar profiles of sound speed
and density as well as the depth of the convective zone and the helium
abundance. The disagreements for models with the new abundances range
from factors of several to many times the quoted uncertainties in the
helioseismological measurements. The disagreements are at temperatures
that are too low to affect significantly solar neutrino emission. If
errors in the calculated OPAL opacities are solely responsible for the
disagreements, then the corrections in the opacity must extend from
2×106 K (R=0.7 Rsolar) to 5×106 K
(R=0.4 Rsolar), with opacity increases of the order of 10%.
Title: Solar Neutrinos: A Popular Account
Authors: Bahcall, John N.
Bibcode: 2004physics..11190B
Altcode:
This encyclopedia article addresses questions like the following. How
does the Sun shine? Does the neutrino have a mass? Are there weak
interactions beyond those described by the standard model of particle
physics?
Title: Helioseismological Implications of Recent Solar Abundance
Determinations
Authors: Serenelli, A. M.; Bahcall, J. N.; Basu, S.; Pinsonneault,
M. H.
Bibcode: 2004ESASP.559..623S
Altcode: 2004soho...14..623S
No abstract at ADS
Title: How Accurately Can We Calculate the Depth of the Solar
Convective Zone?
Authors: Bahcall, John N.; Serenelli, Aldo M.; Pinsonneault, Marc
Bibcode: 2004ApJ...614..464B
Altcode: 2004astro.ph..3604B
We evaluate the logarithmic derivative of the depth of the solar
convective zone (CZ) with respect to the logarithm of the radiative
opacity, ∂lnRCZ/∂lnκ. We use this expression to
show that the radiative opacity near the base of the solar CZ
must be known to an accuracy of +/-1% in order to calculate the
CZ depth to the accuracy of the helioseismological measurement,
RCZ=0.713+/-0.001 Rsolar. The radiative opacity
near the base of the CZ that is obtained from OPAL tables must be
increased by ~21% in the 2004 Bahcall-Pinsonneault solar model if
one wants to invoke opacity errors in order to reconcile recent solar
heavy abundance determinations with the helioseismological measurement
of RCZ. We show that the radiative opacity near the base of
the CZ depends sensitively on the assumed heavy-element mass fraction,
Z. The uncertainty in the measured value of Z is currently the limiting
factor in our ability to calculate the depth of the CZ. Different
state-of-the-art interpolation schemes using the existing OPAL tables
yield opacity values that differ by ~4%. We describe the finer grid
spacings that are necessary to interpolate the radiative opacity to
+/-1%. Uncertainties due to the equation of state do not significantly
affect the calculated depth of the CZ.
Title: Solar Neutrinos Before and After Neutrino 2004
Authors: Bahcall, John N.; Gonzalez-Garcia, M. C.; Pena-Garay, Carlos
Bibcode: 2004JHEP...08..016B
Altcode: 2004hep.ph....6294B
We compare, using a three neutrino analysis, the allowed neutrino
oscillation parameters and solar neutrino fluxes determined by the
experimental data available Before and After Neutrino 2004. New data
available after Neutrino 2004 include refined KamLAND and gallium
measurements. We use six different approaches to analyzing the KamLAND
data. We present detailed results using all the available neutrino
and anti-neutrino data for Deltam221, tan
2theta12, sin 2theta13,
and sin 2eta (sterile fraction). Using the same complete
data sets, we also present Before and After determinations of all the
solar neutrino fluxes (which are treated as free parameters), an upper
limit to the luminosity fraction associated with CNO neutrinos, and
the predicted rate for a 7Be solar neutrino experiment. The
1sigma (3sigma) allowed range of Deltam221 =
8.2+0.3-0.3(+1.0-0.8)
× 10-5 eV2 is decreased by a factor of
1.7 (5), but the allowed ranges of all other neutrino oscillation
parameters and neutrino fluxes are not significantly changed. Maximal
theta12 mixing is disfavored at 5.8sigma and the bound
on the mixing angle theta13 is slightly improved to sin
2theta13<0.048 at 3sigma. The predicted
rate in a 7Be neutrino-electron scattering experiment is
0.665+/-0.015 (+0.045-0.040) of the rate implied
by the BP04 solar model in the absence of neutrino oscillations. The
corresponding predictions for p-p and pep experiments are, respectively,
0.707+0.011-0.013(+0.041-0.039)
and
0.644+0.011-0.013(+0.045-0.037).
In order to clarify what measurements constrain which parameters
best, we also analyze the solar neutrino data separately and the
reactor anti-neutrino data separately, both Before and After Neutrino
2004. We derive upper limits to CPT violation in the weak sector by
comparing reactor anti-neutrino oscillation parameters with neutrino
oscillation parameters. We also show that the recent data disfavor at
91% CL a proposed non-standard interaction description of solar neutrino
oscillations. We have verified that our results are insensitive (changes
much less than 1sigma) to which of six approaches we use in analyzing
the KamLAND data, which of the published 8B neutrino energy
spectra we adopt, and the precise value of the gallium solar neutrino
event rate.
Title: What can we learn from neutrinoless double beta decay
experiments?
Authors: Bahcall, John N.; Murayama, Hitoshi; Peña-Garay, C.
Bibcode: 2004PhRvD..70c3012B
Altcode: 2004hep.ph....3167B
We assess how well next-generation neutrinoless double beta decay and
normal neutrino beta decay experiments can answer four fundamental
questions. (1) If neutrinoless double beta decay searches do not detect
a signal, and if the spectrum is known to be inverted hierarchy, can
we conclude that neutrinos are Dirac particles? (2) If neutrinoless
double beta decay searches are negative and a next-generation ordinary
beta decay experiment detects the neutrino mass scale, can we conclude
that neutrinos are Dirac particles? (3) If neutrinoless double beta
decay is observed with a large neutrino mass element, what is the total
mass in neutrinos? (4) If neutrinoless double beta decay is observed,
but next-generation beta decay searches for a neutrino mass only set
a mass upper limit, can we establish whether the mass hierarchy is
normal or inverted? We base our answers on the expected performance
of next-generation neutrinoless double beta decay experiments and on
simulations of the accuracy of calculations of nuclear matrix elements.
Title: Solving the Mystery of the Missing Neutrinos
Authors: Bahcall, John
Bibcode: 2004physics...6040B
Altcode:
The three years 2001 to 2003 were the golden years of solar neutrino
research. In this period, scientists solved a mystery with which they
had been struggling for four decades. The solution turned out to be
important for both physics and for astronomy. In this article, I tell
the story of those fabulous three years.
Title: Solar models and solar neutrino oscillations
Authors: Bahcall, John N.; Peña-Garay, Carlos
Bibcode: 2004NJPh....6...63B
Altcode: 2004hep.ph....4061B
We provide a summary of the current knowledge, theoretical and
experimental, of solar neutrino fluxes and of the masses and mixing
angles that characterize solar neutrino oscillations. We also summarize
the principal reasons for performing new solar neutrino experiments
and what we anticipate from future studies.
Title: Status of the IceCube Neutrino Observatory
Authors: Ahrens, J.; Bahcall, J. N.; Bai, X.; Bay, R. C.; Becka, T.;
Becker, K. -H.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson,
D. Z.; Blaufuss, E.; Boersma, D. J.; Böser, S.; Bohm, C.; Botner, O.;
Bouchta, A.; Bouhali, O.; Burgess, T.; Carithers, W.; Castermans, T.;
Cavin, J.; Chinowsky, W.; Chirkin, D.; Collin, B.; Conrad, J.; Cooley,
J.; Cowen, D. F.; Davour, A.; De Clercq, C.; DeYoung, T.; Desiati,
P.; Ehrlich, R.; Ellsworth, R. W.; Evenson, P. A.; Fazely, A. R.;
Feser, T.; Gaisser, T. K.; Gallagher, J.; Ganugapati, R.; Geenen,
H.; Goldschmidt, A.; Goodman, J. A.; Gunasingha, R. M.; Hallgren,
A.; Halzen, F.; Hanson, K.; Hardtke, R.; Hauschildt, T.; Hays, D.;
Helbing, K.; Hellwig, M.; Herquet, P.; Hill, G. C.; Hubert, D.;
Hughey, B.; Hulth, P. O.; Hultqvist, K.; Hundertmark, S.; Jacobsen,
J.; Japaridze, G. S.; Jones, A.; Karle, A.; Kawai, H.; Kestel, M.;
Kitamura, N.; Koch, R.; Köpke, L.; Kowalski, M.; Lamoureux, J. I.;
Leich, H.; Liubarsky, I.; Madsen, J.; Matis, H. S.; McParland, C. P.;
Messarius, T.; Mészáros, P.; Minaeva, Y.; Minor, R. H.; Miočinović,
P.; Miyamoto, H.; Morse, R.; Nahnhauer, R.; Neunhöffer, T.; Niessen,
P.; Nygren, D. R.; Ögelman, H.; Olbrechts, Ph; Patton, S.; Paulos,
R.; Pérez de los Heros, C.; Pohl, A. C.; Pretz, J.; Price, P. B.;
Przybylski, G. T.; Rawlins, K.; Razzaque, S.; Resconi, E.; Rhode,
W.; Ribordy, M.; Richter, S.; Sander, H. -G.; Schinarakis, K.;
Schlenstedt, S.; Schneider, D.; Schwarz, R.; Seckel, D.; Smith, A. J.;
Solarz, M.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.;
Steele, D.; Steffen, P.; Stezelberger, T.; Stokstad, R. G.; Sulanke,
K. -H.; Sullivan, G. W.; Sumner, T. J.; Taboada, I.; Tilav, S.;
van Eijndhoven, N.; Wagner, W.; Walck, C.; Wang, R. -R.; Wiebusch,
C. H.; Wiedemann, C.; Wischnewski, R.; Wissing, H.; Woschnagg, K.;
Yoshida, S.; IceCube Collaboration
Bibcode: 2004NewAR..48..519A
Altcode: 2004NewAR..48..519I
The IceCube neutrino telescope, to be constructed near the Antarctic
South Pole, represents the next generation of neutrino telescope. Its
large 1 km 3 size will make it uniquely sensitive to the
detection of neutrinos from astrophysical sources. The current design
of the detector is presented. The basic performance of the detector
and its ability to search for neutrinos from various astrophysical
sources has been studied using detailed simulations and is discussed.
Title: What Do We (Not) Know Theoretically about Solar Neutrino
Fluxes?
Authors: Bahcall, John N.; Pinsonneault, M. H.
Bibcode: 2004PhRvL..92l1301B
Altcode: 2004astro.ph..2114B
Solar model predictions of 8B and p-p neutrinos agree
with the experimentally determined fluxes (including oscillations):
φ(pp)measured=(1.02±00.02±0.01)φ(pp)theory and
φ(8B)measured=(0.88±0.04±0.23)φ(8B)theory,
1σ experimental and theoretical uncertainties, respectively. We
use improved input data for nuclear fusion reactions, the
equation of state, and the chemical composition of the Sun. The
solar composition is the dominant uncertainty in calculating the
8B and CNO neutrino fluxes; the cross section for the
3He(4He,γ)7Be reaction is the most
important uncertainty for the calculated 7Be neutrino flux.
Title: Sensitivity of the IceCube detector to astrophysical sources
of high energy muon neutrinos
Authors: Ahrens, J.; Bahcall, J. N.; Bai, X.; Bay, R. C.; Becka, T.;
Becker, K. -H.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson,
D. Z.; Biron, A.; Blaufuss, E.; Boersma, D. J.; Böser, S.; Bohm, C.;
Botner, O.; Bouchta, A.; Bouhali, O.; Burgess, T.; Carithers, W.;
Castermans, T.; Cavin, J.; Chinowsky, W.; Chirkin, D.; Collin, B.;
Conrad, J.; Cooley, J.; Cowen, D. F.; Davour, A.; de Clercq, C.; De
Young, T.; Desiati, P.; Ehrlich, R.; Ellsworth, R. W.; Evenson, P. A.;
Fazely, A. R.; Feser, T.; Gaisser, T. K.; Gallagher, J.; Ganugapati,
R.; Geenen, H.; Goldschmidt, A.; Goodman, J. A.; Gunasingha, R. M.;
Hallgren, A.; Halzen, F.; Hanson, K.; Hardtke, R.; Hauschildt,
T.; Hays, D.; Helbing, K.; Hellwig, M.; Herquet, P.; Hill, G. C.;
Hubert, D.; Hughey, B.; Hulth, P. O.; Hultqvist, K.; Hundertmark,
S.; Jacobsen, J.; Japaridze, G. S.; Jones, A.; Karle, A.; Kawai,
H.; Kestel, M.; Kitamura, N.; Koch, R.; Köpke, L.; Kowalski, M.;
Lamoureux, J. I.; Leich, H.; Leuthold, M.; Liubarsky, I.; Madsen,
J.; Matis, H. S.; McParland, C. P.; Messarius, T.; Mészáros, P.;
Minaeva, Y.; Minor, R. H.; Miočinović, P.; Miyamoto, H.; Morse, R.;
Nahnhauer, R.; Neunhöffer, T.; Niessen, P.; Nygren, D. R.; Ögelman,
H.; Olbrechts, Ph.; Patton, S.; Paulos, R.; Pérez de Los Heros, C.;
Pohl, A. C.; Pretz, J.; Price, P. B.; Przybylski, G. T.; Rawlins, K.;
Razzaque, S.; Resconi, E.; Rhode, W.; Ribordy, M.; Richter, S.; Sander,
H. -G.; Schinarakis, K.; Schlenstedt, S.; Schmidt, T.; Schneider, D.;
Schwarz, R.; Seckel, D.; Smith, A. J.; Solarz, M.; Spiczak, G. M.;
Spiering, C.; Stamatikos, M.; Stanev, T.; Steele, D.; Steffen, P.;
Stezelberger, T.; Stokstad, R. G.; Sulanke, K. -H.; Sullivan, G. W.;
Sumner, T. J.; Taboada, I.; Tilav, S.; van Eijndhoven, N.; Wagner, W.;
Walck, C.; Wang, R. -R.; Wiebusch, C. H.; Wiedemann, C.; Wischnewski,
R.; Wissing, H.; Woschnagg, K.; Yoshida, S.
Bibcode: 2004APh....20..507A
Altcode: 2003astro.ph..5196A; 2003astro.ph..5196T
We present results of a Monte Carlo study of the sensitivity of
the planned IceCube detector to predicted fluxes of muon neutrinos
at TeV to PeV energies. A complete simulation of the detector and
data analysis is used to study the detector's capability to search
for muon neutrinos from potential sources such as active galaxies
and gamma-ray bursts (GRBs). We study the effective area and the
angular resolution of the detector as a function of muon energy
and angle of incidence. We present detailed calculations of the
sensitivity of the detector to both diffuse and pointlike neutrino
fluxes, including an assessment of the sensitivity to neutrinos
detected in coincidence with GRB observations. After three years
of data taking, IceCube will be able to detect a point-source flux of
Eν2×dNν/dEν=7×10-9
cm-2s-1GeV at a 5σ significance, or,
in the absence of a signal, place a 90% c.l. limit at a level of
Eν2×dNν/dEν=2×10-9
cm-2s-1GeV. A diffuse E-2
flux would be detectable at a minimum strength of
Eν2×dNν/dEν=10-8
cm-2s-1sr-1GeV. A GRB model following
the formulation of Waxman and Bahcall would result in a 5σ effect
after the observation of 200 bursts in coincidence with satellite
observations of the gamma rays.
Title: Distribution of Dark Matter in the Spiral Galaxy NGC 3198
Authors: van Albada, T. S.; Begeman, K.; Sanscisi, R.; Bahcall, J. N.
Bibcode: 2004dmu..book....7V
Altcode:
Two-component mass models, consisting of an exponential disk and
a spherical halo, are constructed to fit a newly determined
rotation curve of NGC 3198 that extends to 11 disk scale
lengths. The amount of dark matter inside the last point of the
rotation curve, at 30 kpc, is at least 4 times larger than the
amount of visible matter, with (M/LB)tot =
18M⊙/LB⊙. The maximum mass-to-light ratio
for the disk is M/LB = 3.6. The available data cannot
discriminate between disk models with low M/L and high M/L, but we
present arguments which suggest that the true mass-to-light ratio
of the disk is close to the maximum computed value. The core radius
of the distribution of dark matter is found to satisfy 1.7 <
Rcore < 12.5 kpc.
Title: M Dwarfs from Hubble Space Telescope Star Counts. V. The
I-Band Luminosity Function
Authors: Zheng, Zheng; Flynn, Chris; Gould, Andrew; Bahcall, John N.;
Salim, Samir
Bibcode: 2004ApJ...601..500Z
Altcode: 2003astro.ph..8359Z
We derive the disk I-band luminosity function from the Zheng et
al. sample of ~1400 disk M dwarfs observed with the Hubble Space
Telescope. We adopt a Galactic-height-dependent color-magnitude relation
to account for the metallicity gradient above the Galactic plane. The
resultant I-band luminosity function peaks at MI~9.5 and
drops sharply toward MI~10.5. Based on observations with
the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope
Science Institute, which is operated by the Association of Universities
for Research in Astronomy, Inc., under NASA contract NAS5-26555.
Title: Dark Matter in the Universe (Second Edition) - 4th Jerusalem
Winter School for Theoretical Physics Lectures
Authors: Bahcall, John; Piran, Tsvi; Weinberg, Steven
Bibcode: 2004dmu..book.....B
Altcode:
No abstract at ADS
Title: Some Possible Regularities in Missing Mass
Authors: Bahcall, John N.; Casertano, Stefano
Bibcode: 2004dmu..book...25B
Altcode:
The unseen matter in a sample of spiral galaxies exhibits simple
regularities and characteristic numerical values.
Title: Introduction
Authors: Bahcall, John N.
Bibcode: 2004dmu..book....1B
Altcode:
Every so often in the history of physics a golden opportunity for
great progress becomes apparent to contemporary physicists. In the
twentieth century, enormous progress was made when, for example,
the regularities of atomic spectra became apparent, when the Lamb
shift was measured, and when the symmetries of supposedly elementary
particles were recognized…
Title: Does the Fine-Structure Constant Vary with Cosmological Epoch?
Authors: Bahcall, John N.; Steinhardt, Charles L.; Schlegel, David
Bibcode: 2004ApJ...600..520B
Altcode: 2003astro.ph..1507B
We use the strong nebular emission lines of O III,
λλ5007 and 4959, to set a robust upper limit on the
time dependence of the fine-structure constant. We find
α-1dα(t)/dt<2×10-13 yr-1,
corresponding to Δα/α(0)=(0.7+/-1.4)×10-4 for
quasars with 0.16<z<0.80 obtained from the SDSS Early Data
Release. Using a blind analysis, we show that the upper limit given
here is invariant with respect to 17 different ways of selecting the
sample and analyzing the data. As a by-product, we show that the ratio
of transition probabilities corresponding to the λλ5007 and 4959
lines is 2.99+/-0.02, in good agreement with (but more accurate than)
theoretical estimates. We compare and contrast the O III emission line
method used here with the many-multiplet method that was used recently
to suggest evidence for a time-dependent α. In an appendix we analyze
the quasars from the recently available SDSS Data Release One sample
and find Δα/α(0)=(1.2+/-0.7)×10-4.
Title: Exploring Galactic Structure with the Fan Mountain Observatory
Bench Spectrograph
Authors: Crane, J. D.; Majewski, S. R.; Patterson, R. J.; Bahcall,
J. N.; Skrutskie, M. F.; Rhee, J.; Frinchaboy, P. M.
Bibcode: 2003AAS...20311206C
Altcode: 2003BAAS...35.1384C
The Bench Spectrograph at the University of Virginia's Fan Mountain
Observatory has recently seen first light through the facility's
primary research telescope, the 1-meter astrometric reflector. As a
single-object, fiber-fed instrument with moderate resolution (5-10
km s-1) capabilities, the spectrograph was motivated
by several ongoing projects requiring stellar spectroscopy at the
University of Virginia. The spectrograph was designed to supply moderate
resolution Northern hemisphere spectra needed for the Grid Giant Star
Survey (GGSS), which in addition to identifying candidates for the
Astrometric Grid of NASA's Space Interferometry Mission (SIM), will
provide a unique, unfilled all-sky catalog of low metallicity halo
K giants that may be used to address a host of problems related to
Galactic structure and kinematics. Because the GGSS candidate sample is
extensive, bright (V<13), and uniformly distributed over the sky,
a fiber-fed design was selected to provide maximal spectral stability
and uniformity while optimizing observing efficiency. The spectrograph
will be useful for observing stars brighter than V ∼14 throughout
the optical spectrum. The instrument will also be used to estimate the
dark matter content of the local Galactic disk by measuring dynamically
the local disk volume density (the ``Oort limit'') reflected by the
motions of a set of K giant ``tracers'' photometrically selected
from a large-area survey of the North Galactic Pole. The Fan Mountain
spectrograph will be used to refine our sample to the best possible
homogeneity and to determine radial velocities. Once complete, this
study should provide the largest and most reliable sample of dynamical
``Oort limit'' tracers assembled to date.
Title: A road map to solar neutrino fluxes, neutrino oscillation
parameters, and tests for new physics
Authors: Bahcall, John N.; Peña-Garay, Carlos
Bibcode: 2003JHEP...11..004B
Altcode: 2003hep.ph....5159B
We analyze all available solar and related reactor neutrino experiments,
as well as simulated future 7Be, p-p, and pep solar neutrino
experiments. We treat all solar neutrino fluxes as free parameters
subject to the condition that the total luminosity represented by
the neutrinos equals the observed solar luminosity (the `luminosity
constraint'). Existing experiments plus the luminosity constraint show
that the p-p solar neutrino flux is 1.02+/-0.02 (1sigma) times the flux
predicted by the BP00 standard solar model; the 7Be neutrino
flux is 0.93+0.25-0.63 the predicted flux;
and the 8B flux is 1.01+/-0.04 the predicted flux. The
CNO fluxes are very poorly determined. The neutrino oscillation
parameters are: Deltam2 = 7.3+0.4-0.6
× 10-5 eV2 and tan 2theta12
= 0.41+/-0.04. We evaluate how accurate future experiments must
be to determine more precisely neutrino oscillation parameters
and solar neutrino fluxes, and to elucidate the transition from
vacuum-dominated to matter-dominated oscillations at low energies. A
future 7Be nu-e scattering experiment accurate to +/-10% can
reduce the uncertainty in the experimentally determined 7Be
neutrino flux by a factor of four and the uncertainty in the p-p
neutrino flux by a factor of 2.5 (to +/-0.8%). A future p-p experiment
must be accurate to better than +/-3% to shrink the uncertainty in tan
2theta12 by more than 15%. The idea that the Sun
shines because of nuclear fusion reactions can be tested accurately by
comparing the observed photon luminosity of the Sun with the luminosity
inferred from measurements of solar neutrino fluxes. Based upon
quantitative analyses of present and simulated future experiments, we
answer the question: Why perform low-energy solar neutrino experiments?
Title: Solar Models and Solar Neutrinos
Authors: Bahcall, John N.
Bibcode: 2003phco.conf...31B
Altcode: 2003astro.ph.10030B
I summarize 40 years of development of the standard solar model that
is used to predict solar neutrino fluxes and then describe the current
uncertainties in the predictions. I will also attempt to explain why
it took so long, about three and a half decades, to reach a consensus
view that new physics is being learned from solar neutrino experiments.
Title: Does the Sun Shine by pp or CNO Fusion Reactions?
Authors: Bahcall, John N.; Gonzalez-Garcia, M. C.; Peña-Garay, Carlos
Bibcode: 2003PhRvL..90m1301B
Altcode: 2002astro.ph.12331B
We show that solar neutrino experiments set an upper limit of 7.8%
(7.3% including the recent KamLAND measurements) to the fraction of
energy that the Sun produces via the CNO fusion cycle, which is an
order of magnitude improvement upon the previous limit. New experiments
are required to detect CNO neutrinos corresponding to the 1.5% of the
solar luminosity that the standard solar model predicts is generated
by the CNO cycle.
Title: IceCube - the next generation neutrino telescope at the
South Pole
Authors: Karle, A.; Ahrens, J.; Bahcall, J. N.; Bai, X.; Becka, T.;
Becker, K. -H.; Besson, D. Z.; Berley, D.; Bernardini, E.; Bertrand,
D.; Binon, F.; Biron, A.; Böser, S.; Bohm, C.; Botner, O.; Bouhali,
O.; Burgess, Th.; Castermans, T.; Chirkin, D.; Conrad, J.; Cooley, J.;
Cowen, D. F.; Davour, A.; de Clercq, C.; De Young, T.; Desiati, P.;
Dewulf, J. -P.; Dingus, B.; Ellsworth, R.; Evenson, P. A.; Fazely,
A. R.; Feser, T.; Gaisser, T. K.; Gallagher, J.; Ganugapati, R.;
Goldschmidt, A.; Goodman, J.; Hallgren, A.; Halzen, F.; Hanson,
K.; Hardtke, R.; Hauschildt, T.; Hellwig, M.; Herquet, P.; Hill,
G. C.; Hulth, P. O.; Hultgvist, K.; Hundertmark, S.; Jacobsen, J.;
Japaridze, G. S.; Karle, A.; Köpke, L.; Kowalski, M.; Lamoureux,
J. I.; Leich, H.; Leuthold, M.; Lindahl, P.; Liubarsky, I.; Madson,
J.; Marciniewski, P.; Matis, H. S.; McParland, C. P.; Minaeva, Y.;
Miočinović, P.; Morse, R.; Nahnhauer, R.; Neunhöffer, T.; Niessen,
P.; Nygren, D. R.; Ogelman, H.; Olbrechts, Ph.; Pérez de Los Heros,
C.; Pohl, A. C.; Price, P. B.; Przybylski, G. T.; Rawlins, K.; Resconi,
E.; Rhode, W.; Ribordy, M.; Richter, S.; Sander, H. -G.; Schmidt, T.;
Schneider, D.; Seckel, D.; Solarz, M.; Sparke, L.; Spiczak, G. M.;
Spiering, C.; Stanev, T.; Steele, D.; Steffen, P.; Stokstad, R. G.;
Sudhoff, P.; Sulanke, K. -H.; Sullivan, G. W.; Sumners, T.; Taboada,
I.; Thollander, L.; Tilav, S.; Walck, C.; Weinheimer, C.; Wiebusch,
C. H.; Wiedemann, Ch.; Wischnewski, R.; Wissing, H.; Woschnagg, K.;
Yoshida, Sh.
Bibcode: 2003NuPhS.118..388K
Altcode: 2002astro.ph..9556K
IceCube is a large neutrino telescope of the next generation to be
constructed in the Antarctic Ice Sheet near theSouth Pole. We present
the conceptual design and the sensitivity of the IceCube detector to
predicted fluxes of neutrinos, both atmospheric and extra-terrestrial. A
complete simulation of the detector design has been used to study the
detector's capability to search for neutrinos from sources such as
active galaxies, and gamma-ray bursts.
Title: Solar models: An historical overview
Authors: Bahcall, John N.
Bibcode: 2003NuPhS.118...77B
Altcode: 2002astro.ph..9080B
I will summarize in four slides the 40 years of development of the
standard solar model that is used to predict solar neutrino fluxes
and then describe the current uncertainties in the predictions. I will
dispel the misconception that the p-p neutrino flux is determined by the
solar luminosity and present a related formula that gives, in terms of
the p-p and 7Be neutrino fluxes, the ratio of the rates of
the two primary ways of terminating the p-p fusion chain. I will also
attempt to explain why it took so long, about three and a half decades,
to reach a consensus view that new physics is being learned from solar
neutrino experiments. Finally, I close with a personal confession.
Title: Has the GZK suppression been discovered?
Authors: Bahcall, John N.; Waxman, Eli
Bibcode: 2003PhLB..556....1B
Altcode: 2002hep.ph....6217B
The energy spectra of ultra-high energy cosmic rays reported by the
AGASA, Fly's Eye, Haverah Park, HiRes, and Yakutsk experiments are
all shown to be in agreement with each other for energies below
1020 eV (after small adjustments, within the known
uncertainties, of the absolute energy scales). The data from HiRes,
Fly's Eye, and Yakutsk are consistent with the expected flux suppression
above 5×1019 eV due to interactions of cosmic rays with
the cosmic microwave background, the Greisen-Zatsepin-Kuzmin (GZK)
suppression, and are inconsistent with a smooth extrapolation of the
observed cosmic-ray energy spectrum to energies >5×1019
eV. AGASA data show an excess of events above 1020 eV,
compared to the predicted GZK suppression and to the flux measured by
the other experiments.
Title: Solar Neutrinos Before and After KamLAND
Authors: Bahcall, John N.; Concepcion Gonzalez-Garcia, M.; na-Garay,
Carlos Pe
Bibcode: 2003JHEP...02..009B
Altcode: 2002hep.ph...12147B
We use the recently reported KamLAND measurements on oscillations of
reactor anti-neutrinos, together with the data of previously reported
solar neutrino experiments, to show that: (1) the total 8B neutrino flux
emitted by the Sun is 1.00(1.0 +/- 0.06) of the standard solar model
(BP00) predicted flux, (2) the fraction of the 8B flux that is in the
form of sterile neutrinos is 0.00+0.09-0.00,
(3) the KamLAND measurements reduce the area of the globally allowed
oscillation regions that must be explored in model fitting by six orders
of magnitude in the Deltam2-tan 2theta plane,
(4) LMA is now the unique oscillation solution to a CL of 4.7sigma,
(5) maximal mixing is disfavored at 3.3 sigma, (6) active-sterile
admixtures are constrained to sin 2eta < 0.13, and (7)
non-standard solar models that were invented to completely avoid solar
neutrino oscillations are excluded by KamLAND (KamLAND plus solar)
at 3.6 (7.9) sigma. We also refine quantitative predictions for future
7Be and p-p solar neutrino experiments.
Title: Mapping Globular Cluster Tidal Streams
Authors: Grillmair, Carl J.; Bahcall, John; Geisler, Douglas; Gieren,
Wolfgang; Grebel, Eva; Irwin, Michael; Johnston, Kathryn; Majewski,
Steven; Patterson, Richard; Reid, Neill; Spergel, David; Tremaine,
Scott
Bibcode: 2003noao.prop..215G
Altcode:
The primary scientific goal of this program is to detect and map
the tidal streams emanating from halo globular clusters. We propose
to obtain moderately deep V and I imaging of the regions within 2°
of the centers of five globular clusters with R_sun < 50 kpc and
with a high probability of having strong tidal tails. Given that
these cold tidal streams are on essentially the same orbits as their
parent clusters, they can be used to constrain both the formation and
evolution of the Galactic halo as well as the present shape of the
Galactic potential field. With follow-up spectroscopy to eliminate
foreground contaminants, the stars in these tidal streams will be used
to construct a high-priority target list for the Space Interferometry
Mission (SIM). Proper motion measurements of these stars with SIM will
enable us to tightly constrain the detailed, three-dimensional structure
of the Galactic potential field from the Solar Circle out to 50 kpc.
Title: Solar models: structure, neutrinos, and helioseismological
properties
Authors: Bahcall, J. N.; Basu, S.; Pinsonneault, M. H.
Bibcode: 2003dysu.book....8B
Altcode:
Solar models remain at the frontiers of two different scientific
disciplines solar neutrino studies and helioseismology. After presenting
the details of some state-of-the-art solar models, this chapter gives
an overview of solar neutrino physics in some detail. The neutrino
predictions from the set of solar models discussed have been contrasted
with the results of the solar neutrino experiments. Finally, the
structure of the solar models are compared with helioseismic results
obtained using different data sets.
Title: Astrophysical Neutrinos:. 20<LC>th</LC> Century
and Beyond
Authors: Bahcall, J. N.
Bibcode: 2002nmgm.meet..190B
Altcode:
I summarize the first four decades of solar neutrino research and
suggest what may be possible to learn with extragalactic neutrinos
and with solar neutrinos in the next decade.
Title: The Birth of the HST Snapshot Programs
Authors: Bahcall, John N.
Bibcode: 2002astro.ph.11193B
Altcode:
This article describes the unconventional and occassionally stormy
birth and early history of the HST Snapshot Program.
Title: If sterile neutrinos exist, how can one determine the total
solar neutrino fluxes?
Authors: Bahcall, John N.; Gonzalez-Garcia, M. C.; Peña-Garay, C.
Bibcode: 2002PhRvC..66c5802B
Altcode: 2002hep.ph....4194B
The 8B solar neutrino flux inferred from a global analysis
of solar neutrino experiments is within 11% (1σ) of the predicted
standard solar model value if only active neutrinos exist, but could
be as large as 1.7 times the standard prediction if sterile neutrinos
exist. We show that the total 8B neutrino flux (active
plus sterile neutrinos) can be determined experimentally to about 10%
(1σ) by combining charged current measurements made with the KamLAND
reactor experiment and with the SNO CC solar neutrino experiment,
provided the LMA neutrino oscillation solution is correct and the
simulated performance of KamLAND is valid. Including also SNO NC
data, the sterile component of the 8B neutrino flux can
be measured by this method to an accuracy of about 12% (1σ) of the
standard solar model flux. Combining Super-Kamiokande and KamLAND
measurements and assuming the oscillations occur only among active
neutrinos, the 8B neutrino flux can be measured to 6% (1σ)
the total flux can be measured to an accuracy of about 9%. The total
7Be solar neutrino flux can be determined to an accuracy
of about 28% (1σ) by combining measurements made with the KamLAND,
SNO, and gallium neutrino experiments. One can determine the total
7Be neutrino flux to a 1σ accuracy of about 11% or better
by comparing data from the KamLAND experiment and the BOREXINO solar
neutrino experiment provided both detectors work as expected. The
pp neutrino flux can be determined to about 15% using data from the
gallium, KamLAND, BOREXINO, and SNO experiments.
Title: Before and After: How has the SNO NC measurement changed
things?
Authors: Bahcall, John N.; Gonzalez-Garcia, Concepción M.; Pena-Garay,
Carlos
Bibcode: 2002JHEP...07..054B
Altcode: 2002hep.ph....4314B
We present `Before and After' global oscillation solutions, as well as
predicted `Before and After' values and ranges for ten future solar
neutrino observables (for BOREXINO, KamLAND, SNO, and a generic p-p
neutrino detector). The `Before' case includes all solar neutrino data
(and some theoretical improvements) available prior to April 20, 2002
and the `After' case includes, in addition, the new SNO data on the
CC, NC, and day-night asymmetry. We have performed global analyses
using the full SNO day-night energy spectrum and, alternatively,
using just the SNO NC and CC rates and the day-night asymmetry. The
LMA solution is the only currently allowed MSW oscillation solution
at ~ 99% CL. The LOW solution is allowed only at more than 2.5sigma,
SMA is now excluded at 3.7sigma or 4.7sigma depending upon analysis
strategy, and pure sterile oscillations are excluded at more than
4.7sigma. Small mixing angles are `out' (pure sterile is `way out');
MSW with large mixing angles is definitely `in'. Vacuum oscillations
are allowed at 3sigma, but not at 2sigma. Precise maximal mixing is
excluded at 3.2sigma for MSW solutions and at more than 2.8sigma for
vacuum solutions. Most of the predicted values for future observables
for the BOREXINO, KamLAND, and future SNO measurements are changed only
by minor amounts by the inclusion of the recent SNO data. In order to
test the robustness of the allowed neutrino oscillation regions that
are inferred from the measurements and the predicted values for future
solar neutrino observables, we have carried out calculations using a
variety of strategies for analyzing the SNO and other experimental data.
Title: Erratum: The Salpeter plasma corrections for solar fusion
reactions
Authors: Bahcall, J. N.; Brown, L. S.; Gruzinov, A.; Sawyer, R. F.
Bibcode: 2002A&A...388..660B
Altcode:
In the paper by Bahcall, J. N., Brown, L. S., Gruzinov, A., &
Sawyer, R. F. 2002, A&A, 383, 291, the paper by Weiss, A.,
Fleiskamp, M., & Tsytovich, N. 2001, A&A, 371, 1123 was wrongly
cited as suggesting a modification of the Salpeter formula for screening
of nuclear reactions. The main point of the paper by Weiss et al. was
actually to show that significant deviations from the Salpeter formula
are strongly disfavored by helioseismology measurements.
Title: How accurately can one test CPT conservation with reactor
and solar neutrino experiments?
Authors: Bahcall, John N.; Barger, V.; Marfatia, Danny
Bibcode: 2002PhLB..534..120B
Altcode: 2002hep.ph....1211B
We show that the combined data from solar neutrino experiments and
from the KamLAND reactor neutrino experiment can establish an upper
limit on, or detect, potential CPT violation in the neutrino sector
of order 10-20 to 10-21 GeV.
Title: Robust signatures of solar neutrino oscillation solutions
Authors: Bahcall, John N.; Concepcion Gonzalez-Garcia, M.; Peña-Garay,
Carlos
Bibcode: 2002JHEP...04..007B
Altcode: 2001hep.ph...11150B
With the goal of identifying signatures that select specific neutrino
oscillation parameters, we test the robustness of global oscillation
solutions that fit all the available solar and reactor experimental
data. We use three global analysis strategies previously applied
by different authors and also determine the sensitivity of the
oscillation solutions to the critical nuclear fusion cross section,
S17(0), for the production of 8B. Our standard
results make use of the precise new measurement of S17(0)
by Junghans et al. The globally favored solutions are, in order of
goodness of fit: LMA (the only solution at 2sigma), LOW, and VAC. The
NC to CC ratio for SNO is predicted by the standard global analysis
to be 3.45+0.70-0.54(1sigma) which is separated
from the no-oscillation value of 1.0 by much more than the expected
experimental error. The predicted range of the day-night difference in
CC rates is 8.3+5.0-5.6(1sigma)%. A measurement
by SNO of either a NC to CC ratio > 3.3 or a day-night difference
>10%, would favor a small region of the currently allowed LMA
neutrino parameter space. The global oscillation solution predicts
a 7Be neutrino-electron scattering rate in BOREXINO and
KamLAND in the range 0.65+0.04-0.03(1sigma) of
the BP00 standard solar model rate, a prediction which can be used to
test both the solar model and the neutrino oscillation theory. Only
the LOW solution predicts a large day-night effect (leq 42%, 3sigma)
in BOREXINO and KamLAND. For the reactor KamLAND experiment, the LMA
solution predicts a charged current rate relative to the standard model
of 0.44+0.22-0.07(1sigma), Ethreshold
= 1.22 MeV. We have also evaluated the effects of including preliminary
Super-Kamiokande data for 1496 days of observations.
Title: Measuring Local Dark Matter with K giants at the North
Galactic Pole
Authors: Crane, Jeffrey D.; Majewski, Steven R.; Bahcall, John N.;
Patterson, Richard J.
Bibcode: 2002noao.prop..302C
Altcode:
Local dark matter can be studied by measuring dynamically the local
Galactic disk volume density (the ``Oort limit'' and comparing it to the
volume density one gets by adding up local visible mass components. This
is typically done by measuring the density and dynamics of a sample
of ``tracer'' stars toward the Galactic poles. Using a variety of
tracers and techniques, many such studies have been done, but with
disparate results suggesting everything from no dark matter in the
disk to more dark than visible matter. The construction of a large,
uniform, and systematically well-measured tracer sample is a crucial
part of this method. We have used Washington + DDO photometry to
select a large sample of subsolar metallicity K giants at the North
Galactic Pole. This proposal concerns the collection of spectroscopic
data to refine our sample to the best possible homogeneity to minimize
distance errors and to determine radial velocities. Once complete, this
study should provide the largest and most reliable sample of dynamical
``Oort limit'' tracers yet assembled. As a result, we expect to place
the strongest constraints yet on the density and scale height of dark
matter in the disk. In the future, this same sample will be used in a
Space Interferometry Mission Key Project study of the Oort limit which
will refine our ground-based result by supplying transverse motions that
can be incorporated into a 3-dimensional analysis of the potential and
account for off-diagonal elements of the velocity correlation tensor,
as well as provide extremely good trigonometric parallaxes.
Title: The luminosity constraint on solar neutrino fluxes
Authors: Bahcall, John N.
Bibcode: 2002PhRvC..65b5801B
Altcode: 2001hep.ph....8148B
A specific linear combination of the total solar neutrino fluxes must
equal the measured solar photon luminosity if nuclear fusion reactions
among light elements are responsible for solar energy generation. This
luminosity constraint, previously used in a limited form in testing
the no neutrino oscillation hypothesis, is derived in a generality
that includes all of the relevant solar neutrino fluxes and which is
suitable for analyzing the results of many different solar neutrino
experiments. With or without allowing for neutrino oscillations,
the generalized luminosity constraint can be used in future analyses
of solar neutrino data. Accurate numerical values for the linear
coefficients are provided.
Title: The Salpeter plasma correction for solar fusion reactions
Authors: Bahcall, J. N.; Brown, L. S.; Gruzinov, A.; Sawyer, R. F.
Bibcode: 2002A&A...383..291B
Altcode: 2000astro.ph.10055B
We describe five different ways of obtaining the Salpeter formula for
the plasma corrections to fusion rates; this formula is valid at the
center of the sun with insignificant errors ( ~ percent). Several
recent papers have obtained a variety of answers in conflict with
this result. We analyse the arguments of these papers, identifying
sources of the discrepancies in some cases, and pointing out internal
inconsistencies in the arguments given in other cases.
Title: Astrophysical Neutrinos
Authors: Bahcall, J. N.
Bibcode: 2002IJMPA..17S...6B
Altcode: 2002IJMPA..17....6B
I summarize the first four decades of solar neutrino research and
suggest what may be possible to learn with extragalactic neutrinos
and with solar neutrinos in the next decade.
Title: Taking Measure of the Milky Way
Authors: Majewski, Steven R.; Bahcall, John N.; Geisler, Douglas;
Gieren, Wolfgang; Grebel, Eva; Grillmair, Carl; Irwin, Michael;
Johnston, Kathryn V.; Patterson, Richard J.; Reid, Neill I.; Spergel,
David; Tremaine, Scott
Bibcode: 2002swsi.conf...15M
Altcode:
No abstract at ADS
Title: Solar Neutrinos: An Overview
Authors: Bahcall, J. N.
Bibcode: 2002cocm.book...37B
Altcode:
No abstract at ADS
Title: Astrophysical Neutrinos: 20th Century and Beyond
Authors: Bahcall, J. N.
Bibcode: 2002spod.conf....6B
Altcode:
I summarize the first four decades of solar neutrino research and
suggest what may be possible to learn with extragalactic neutrinos
and with solar neutrinos in the next decade.
Title: How many σ's is the solar neutrino effect?
Authors: Bahcall, John N.
Bibcode: 2001PhRvC..65a5802B
Altcode: 2001hep.ph....8147B; 2002PhRvC..65a5802B
The minimal standard electroweak model can be tested by allowing all
the solar neutrino fluxes, with undistorted energy spectra, to be free
parameters in fitting the measured solar neutrino event rates, subject
only to the condition that the total observed luminosity of the Sun be
produced by nuclear fusion. The rates of the five experiments prior to
SNO (chlorine, Kamiokande, SAGE, GALLEX, Super-Kamiokande) cannot be fit
by an arbitrary choice of undistorted neutrino fluxes at the level of
2.5σ (formally 99% C.L.). Considering just SNO and Super-Kamiokande,
the discrepancy is at the 3.3σ level (10-3 C.L.). If
all six experiments are fit simultaneously, the formal discrepancy
increases to 4σ (7×10-5 C.L.). If the relative scaling in
temperature of the nuclear reactions that produce 7Be and
8B neutrinos is taken into account, the formal discrepancy
is at the 7.4σ level.
Title: How the Sun Shines
Authors: Bahcall, John
Bibcode: 2001Mercu..30e..30B
Altcode:
After nearly two centuries of debate, recent neutrino experiments have
solidified our understanding of solar energy production.
Title: Global analysis of solar neutrino oscillations including SNO
CC measurement
Authors: Bahcall, John N.; Concha Gonzalez-Garcia, M.; Peña-Garay,
Carlos
Bibcode: 2001JHEP...08..014B
Altcode: 2001hep.ph....6258B
For active and sterile neutrinos, we present the globally allowed
solutions for two neutrino oscillations. We include the SNO CC
measurement and all other relevant solar neutrino and reactor
data. Five active neutrino oscillation solutions (LMA, LOW, SMA,
VAC, and Just So2) are currently allowed at 3sigma; three
sterile neutrino solutions (Just So2, SMA, and VAC) are
allowed at 3sigma. The goodness of fit is satisfactory for all eight
solutions. We also investigate the robustness of the allowed solutions
by carrying out global analyses with and without: 1) imposing solar
model constraints on the 8B neutrino flux, 2) including
the Super-Kamiokande spectral energy distribution and day-night data,
3) including a continuous mixture of active and sterile neutrinos,
4) using an enhanced CC cross section for deuterium (due to radiative
corrections), and 5) an optimistic, hypothetical reduction by a factor
of three of the error of the SNO CC rate. For every analysis strategy
used in this paper, the most favored solutions all involve large mixing
angles: LMA, LOW, or VAC. The favored solutions are robust, but the
existence at 3sigma of individual sterile solutions and the active
Just So2 solution is sensitive to the analysis assumptions.
Title: M Dwarfs from Hubble Space Telescope Star Counts. IV.
Authors: Zheng, Zheng; Flynn, Chris; Gould, Andrew; Bahcall, John N.;
Salim, Samir
Bibcode: 2001ApJ...555..393Z
Altcode: 2001astro.ph..2442Z
We study a sample of about 1400 disk M dwarfs that are found in
148 fields observed with the Wide Field Camera 2 (WFC2) on the
Hubble Space Telescope and 162 fields observed with pre-repair
Planetary Camera 1 (PC1), of which 95 of the WFC2 fields are newly
analyzed. The method of maximum likelihood is applied to derive the
luminosity function and the Galactic disk parameters. At first,
we use a local color-magnitude relation and a locally determined
mass-luminosity relation in our analysis. The results are consistent
with those of previous work but with considerably reduced statistical
errors. These small statistical errors motivate us to investigate
the systematic uncertainties. Considering the metallicity gradient
above the Galactic plane, we introduce a modified color-magnitude
relation that is a function of Galactic height. The resultant M
dwarf luminosity function has a shape similar to that derived using
the local color-magnitude relation but with a higher peak value. The
peak occurs at MV~12, and the luminosity function drops
sharply toward MV~14. We then apply a height-dependent
mass-luminosity function interpolated from theoretical models with
different metallicities to calculate the mass function. Unlike the mass
function obtained using local relations, which has a power-law index
α=0.47, the one derived from the height-dependent relations tends
to be flat (α=-0.10). The resultant local surface density of disk
M dwarfs (12.2+/-1.6 Msolar pc-2) is somewhat
smaller than the one obtained using local relations (14.3+/-1.3
Msolar pc-2). Our measurement favors a short
disk scale length, H=2.75+/-0.16 (statistical)+/-0.25 (systematic)
kpc. Based on observations with the NASA/ESA Hubble Space Telescope,
obtained at the Space Telescope Science Institute, which is operated
by the Association of Universities for Research in Astronomy, Inc.,
under NASA contract NAS5-26555.
Title: Solar Models: Current Epoch and Time Dependences, Neutrinos,
and Helioseismological Properties
Authors: Bahcall, John N.; Pinsonneault, M. H.; Basu, Sarbani
Bibcode: 2001ApJ...555..990B
Altcode: 2000astro.ph.10346B
We calculate accurate solar models and report the detailed time
dependences of important solar quantities. We use helioseismology
to constrain the luminosity evolution of the Sun and report the
discovery of semiconvection in evolved solar models that include
diffusion. In addition, we compare the computed sound speeds with
the results of p-mode observations by BiSON, GOLF, GONG, LOWL, and
MDI instruments. We contrast the neutrino predictions from a set
of eight standard-like solar models and four deviant (or deficient)
solar models with the results of solar neutrino experiments. For solar
neutrino and helioseismological applications, we present present-epoch
numerical tabulations of characteristics of the standard solar model
as a function of solar radius, including the principal physical and
composition variables, sound speeds, neutrino fluxes, and functions
needed for calculating solar neutrino oscillations.
Title: High-energy physics: Neutrinos reveal split personalities
Authors: Bahcall, John N.
Bibcode: 2001Natur.412...29B
Altcode:
No abstract at ADS
Title: High energy astrophysical neutrinos: The upper bound is robust
Authors: Bahcall, John; Waxman, Eli
Bibcode: 2001PhRvD..64b3002B
Altcode: 1999hep.ph....2383B
We elucidate the physical basis for the upper bound on high energy
neutrino fluxes implied by the observed cosmic ray flux. We stress that
the bound is valid for neutrinos produced either by p,γ reactions
or by p-p(n) reactions in sources which are optically thin for high
energy protons to photo-meson and nucleon-meson interactions. We show
that the upper bound is robust and conservative. The Waxman-Bahcall
bound overestimates the most likely neutrino flux by a factor ~5/τ,
for small optical depths τ. The upper limit cannot be plausibly evaded
by invoking magnetic fields, optically thick active galactic nuclei
(AGNs), or large hidden fluxes of extragalactic protons. We describe
the implications of the bound for future experiments including the
AMANDA, ANTARES, Auger, ICECUBE, NESTOR, and OWL/AIRWATCH detectors.
Title: Astrophysical neutrinos
Authors: Bahcall, J. N.
Bibcode: 2001NuPhS.100....5B
Altcode:
I summarize the first four decades of solar neutrino research and
suggest what may be possible to learn with extragalactic neutrinos
and with solar neutrinos in the next decade.
Title: Solar neutrinos: global analysis and implications for SNO
Authors: Bahcall, John N.; Krastev, Plamen I.; Smirnov, Alexei Yu.
Bibcode: 2001JHEP...05..015B
Altcode: 2001hep.ph....3179B
We present a global analysis of all the available solar neutrino data
treating consistently the 8B and hep neutrino fluxes as free
parameters. The analysis reveals at 99.7% C.L. eight currently-allowed
discrete regions in two-neutrino oscillation space, five regions
corresponding to active neutrinos and three corresponding to sterile
neutrinos. Most of the allowed oscillation solutions are robust with
respect to changes in the analysis procedures, but the traditional
vacuum solution is fragile. The globally-permitted range of the
8B neutrino flux, 0.45 to 1.95 in units of the BP2000
flux, is comparable to the 3sigma range allowed by the standard
solar model. We discuss the implications for SNO of a low mass,
Deltam2 ~ 6 × 10-12 eV2, vacuum
oscillation solution, previously found by Raghavan, and by Krastev and
Petcov, but absent in recent analyses that included Super-Kamiokande
data. For the SNO experiment, we present refined predictions for
the charged-current rate and the ratio of the neutral-current rate
to charged-current rate. The predicted charged-current rate can be
clearly distinguished from the no-oscillation rate only for the
LMA solution. The predicted ratio of the neutral-current rate to
charged-current rate is distinguishable from the no-oscillation ratio
for the LMA, SMA, LOW, and VAC solutions for active neutrinos.
Title: Taking Measure of the Milky Way
Authors: Majewski, S. R.; Bahcall, J. N.; Geisler, D.; Gieren, W.;
Grebel, E. K.; Grillmair, C.; Irwin, M.; Johnston, K. V.; Patterson,
R. J.; Reid, I. N.; Spergel, D.; Tremaine, S.
Bibcode: 2001AAS...198.6213M
Altcode: 2001BAAS...33..879M
We plan to undertake fundamental measurements of the gravitational
potential (mass distribution) and dynamical structure of the Milky Way
using the Space Interferometry Mission (SIM). Among our goals will be:
1. The determination of two fundamental parameters that play a central
role in virtually every problem in Galactic astronomy, namely (a) the
solar distance to the center of the Milky Way (b) the solar angular
velocity around the Galactic center 2. The measurement of fundamental
dynamical properties of the Milky Way, among them (a) the pattern speed
of the central bar (b) the rotation field and velocity-dispersion
tensor in the disk (c) the kinematics (mean rotational velocity and
velocity dispersion tensor) of the halo as a function of position
3. The definition of the mass distribution of the Galaxy, which is
dominated by the presence of dark matter. We intend to measure (a)
the relative contribution of the disk and halo to the gravitational
potential (b) local volume and surface mass density of the disk (c)
the shape, mass and extent of the dark halo of the Milky Way out to
250 kpc We will take advantage of the data already being obtained for
sub-solar metallicity K giants in the SIM Astrometric Grid. These data
will be supplemented by SIM observations of other targets, among them:
(1) counterparts to the Astrometric Grid stars at greater distances,(2)
a sample of disk Mira and Cepheid variables, (3) a sample of disk
open clusters with a well-defined and restricted age range, (4) the
brightest few stars in every Galactic globular cluster and satellite
dwarf galaxy, and (5) stars in tidal tails of disrupted satellite
galaxies and globular clusters. In addition, we intend to address
the wealth of information these data will yield on Galactic stellar
populations and the insight they will provide into the formation history
of the Milky Way. Therefore, we intend to supplement the astrometric
data with ground-based observations of abundances, radial velocities,
and other properties, to maximize the benefits of the SIM data for
analyses of stellar populations.
Title: Astrophysical Neutrinos:. 20th Century and Beyond
Authors: Bahcall, J. N.
Bibcode: 2001neph.conf...56B
Altcode:
I summarize the first four decades of solar neutrino research and
suggest what may be possible to learn with extragalactic neutrinos
and with solar neutrinos in the next decade.
Title: Neutrino Physics Its Impact on Particle Physics, Astrophysics
and Cosmology
Authors: Bahcall, J.; Haxton, W.; Kubodera, K.; Poole, C.
Bibcode: 2001neph.conf.....B
Altcode:
No abstract at ADS
Title: Correlations of solar neutrino observables for SNO
Authors: Bahcall, John N.; Krastev, Plamen I.; Smirnov, Alexei Yu.
Bibcode: 2001PhRvD..63e3012B
Altcode: 2000hep.ph....6078B
Neutrino oscillation scenarios predict correlations, and zones
of avoidance, among measurable quantities such as spectral energy
distortions, total fluxes, time dependences, and flavor content. The
comparison of observed and predicted correlations will enhance
the diagnostic power of solar neutrino experiments. A general
test of all presently allowed (2ν) oscillation solutions is that
future measurements must yield values outside the predicted zones of
avoidance. To illustrate the discriminatory power of the simultaneous
analysis of multiple observables, we map currently allowed regions
of Δm2-sin2 2θ onto planes of quantities
measurable with the Sudbury Neutrino Observatory (SNO). We calculate the
correlations that are predicted by vacuum and MSW (active and sterile)
neutrino oscillation solutions that are globally consistent with all
available neutrino data. We derive approximate analytic expressions
for the dependence of individual observables and specific correlations
upon neutrino oscillations parameters. We also discuss the prospects
for identifying the correct oscillation solution using multiple SNO
observables.
Title: Solar Neutrinos:. an Overview
Authors: Bahcall, J. N.
Bibcode: 2001ppu..conf...63B
Altcode:
I summarize the current state of solar neutrino research.
Title: Why do Solar Neutrino Experiments Below 1 Mev?
Authors: Bahcall, J. N.
Bibcode: 2001lesn.conf..172B
Altcode: 2001hep.ex....6086B
I discuss why we need solar neutrino experiments below 1 MeV. I
also express my prejudices about the desired number and types of
such experiments, emphasizing the importance of p-p solar neutrino
experiments.
Title: Astrophysical Neutrinos
Authors: Bahcall, J. N.
Bibcode: 2001IJMPA..16.4955B
Altcode: 2000hep.ph....9044B
I summarize the first four decades of solar neutrino research and
suggest what may be possible to learn with extragalactic neutrinos
and with solar neutrinos in the next decade.
Title: Proceedings of the Carolina Symposium on Neutrino Physics
: its impact on particle physics, astrophysics and cosmology :
University of South Carolina, 10-12 March 2000
Authors: Bahcall, John N.; Avignone, F. T.
Bibcode: 2001npip.book.....B
Altcode:
No abstract at ADS
Title: Astrophysical Neutrinos: 20th Century and Beyond
Authors: Bahcall, J. N.
Bibcode: 2001NuPhS..91....9B
Altcode:
I summarize the first four decades of solar neutrino research and
suggest what may be possible to learn with extragalactic neutrinos
and with solar neutrinos in the next decade.
Title: How the Sun Shines
Authors: Bahcall, John N.
Bibcode: 2000JRASC..94..219B
Altcode: 2000astro.ph..9259B
This historical essay describes the struggle to understand how the
sun shines. The story begins with the disagreement between Kelvin and
Darwin over the age of the sun in the middle of the 19th century and
continues through the revelations of solar neutrino experiments at
the conclusion of the 20th century.
Title: Astronomy: The Big Bang is bang on
Authors: Bahcall, John
Bibcode: 2000Natur.408..916B
Altcode:
No abstract at ADS
Title: Solar Interior: Neutrinos
Authors: Bahcall, J.
Bibcode: 2000eaa..bookE2072B
Altcode:
Six experiments have observed solar NEUTRINOS, three of which are
radiochemical experiments: Homestake (chlorine detector), GALLEX
(gallium detector) and SAGE (gallium detectors). These radiochemical
detectors register all neutrinos above a fixed threshold energy (0.8
MeV for chlorine, 0.2 MeV for gallium), with no further information
about energy. Three other experiments, Kamiokande, SUPER-KAMIO...
Title: SNO: Predictions for ten measurable quantities
Authors: Bahcall, John N.; Krastev, Plamen I.; Smirnov, Alexei Yu.
Bibcode: 2000PhRvD..62i3004B
Altcode: 2000hep.ph....2293B
We calculate the range of predicted values for 10 quantities that will
be measured by the Sudbury Neutrino Observatory (SNO). We use neutrino
oscillation solutions (vacuum and MSW; active and sterile neutrinos)
that are globally consistent with all available neutrino data and
estimate realistic theoretical and experimental uncertainties. The
neutral current to charged current double ratio is predicted to be more
than 9σ from the no-oscillation solution for all of the currently
favored neutrino oscillation solutions. The best-fit oscillation
solutions predict a CC day-night rate difference between -0.1% and
+12.5% and a NC day-night difference <0.01%. We present also the
predicted range for the first and the second moments of the charged
current electron recoil energy spectrum, the charged current, the
neutral current, and the ν-e scattering rates, the seasonal dependence
of the charged current rate, and the double ratio of neutrino-electron
scattering rate to charged current rate.
Title: Ultra-High-Energy Cosmic Rays May Come from Clustered Sources
Authors: Bahcall, John N.; Waxman, Eli
Bibcode: 2000ApJ...542..542B
Altcode: 1999hep.ph...12326B
Clustering of cosmic-ray sources affects the flux observed beyond
the cutoff imposed by the cosmic microwave background and may be
important in interpreting the AGASA, Fly's Eye, and HiRes data. The
standard deviation, σ, in the predicted number N of events above
1020 eV is σ/N=0.9(r0/10 Mpc)0.9,
where r0 is the unknown scale length of the correlation
function (r0~=10 Mpc for field galaxies, H0=50
km s-1 Mpc-1). Future experiments will allow the
determination of r0 through the detection of anisotropies
in arrival directions of ~1020 eV cosmic rays over angular
scales of Θ~r0/30 Mpc.
Title: Neutrino Afterglow from Gamma-Ray Bursts: ~1018 EV
Authors: Waxman, Eli; Bahcall, John N.
Bibcode: 2000ApJ...541..707W
Altcode: 1999hep.ph....9286W
We show that a significant fraction of the energy of
a γ-ray burst (GRB) is probably converted to a burst of
1017-1019 eV neutrinos and multiple GeV γ-rays
that follow the main GRB by ~10 s. If GRBs accelerate protons to
~1020 eV, a suggestion that recently gained support from
observations of GRB afterglows, then both the neutrinos and the γ-rays
may be detectable.
Title: Solar neutrinos: an overview
Authors: Bahcall, J. N.
Bibcode: 2000PhR...333...47B
Altcode:
I summarize the current state of solar neutrino research.
Title: Solar neutrinos
Authors: Bahcall, J. N.
Bibcode: 2000AIPC..533...91B
Altcode: 2000hep.ex....2018B
I summarize the current state of solar neutrino research and then
answer the question: What should we do next? .
Title: 5-10 GeV Neutrinos from Gamma-Ray Burst Fireballs
Authors: Bahcall, John N.; Mészáros, Peter
Bibcode: 2000PhRvL..85.1362B
Altcode: 2000hep.ph....4019B
A gamma-ray burst fireball is likely to contain an admixture of
neutrons. Inelastic collisions between differentially streaming
protons and neutrons in the fireball produce νμ
\(ν¯μ\) of ~10 GeV as well as νe
\(ν¯e\) of ~5 GeV, which could produce ~7 events/year
in km3 detectors, if the neutron abundance is comparable
to that of protons. Photons of ~10 GeV from π0 decay and
~100 MeV ν¯e from neutron decay are also produced, but
will be difficult to detect. Photons with energies <~1 MeV from
shocks following neutron decay produce a characteristic signal which
may be distinguishable from the proton-related MeV photons.
Title: The Hubble Space Telescope Quasar Absorption Line Key
Project. XV. Milky Way Absorption Lines
Authors: Savage, Blair D.; Wakker, Bart; Jannuzi, Buell T.; Bahcall,
John N.; Bergeron, Jacqueline; Boksenberg, Alec; Hartig, George F.;
Kirhakos, Sofia; Murphy, Edward M.; Sargent, W. L. W.; Schneider,
Donald P.; Turnshek, David; Wolfe, Arthur M.
Bibcode: 2000ApJS..129..563S
Altcode:
This paper presents the results of an analysis of the Milky Way
absorption lines found in the Hubble Space Telescope (HST) Quasar
Absorption Line Key Project database for 83 QSOs observed with the
Faint Object Spectrograph G190H and G270H gratings, of which 16
QSOs are also observed with the G130H grating. The HST Key Project
observations are supplemented with high-quality 21 cm H I emission-line
observations mostly obtained with the NRAO 43 m radio telescope. The
Milky Way halo gas exhibits ``mixed ionization'' absorption with
high-ionization absorption from Si IV and C IV substantially weaker
than the extremely strong intermediate- and low-ionization absorption
from Si III, Si II, C II, Mg II, and Fe II. For a sample of 16 QSOs
observed in the far-UV, the median velocity equivalent widths of
very strong lines of Si IV, Si III, and Si II are 60, 180, and 180
km s-1, respectively. Velocity equivalent widths this
large for Si III and Si II imply the existence of high velocity
dispersion moderate- (Si III) and low-ionization (Si II) gas along
many paths through the Galactic halo. Measures of the Galactic
damped Lyα line toward 14 QSOs permit the determination of N(H
I)Lyα through the gaseous disk and halo of the Galaxy. The
values of N(H I)Lyα range from 0.64×1020 to
3.37×1020 cm-2 with N(H I)Lyα|sinb|
averaging (1.29+/-0.49)×1020 cm-2. A comparison
of N(H I)Lyα with N(H I)21cm reveals that N(H
I)Lyα/N(H I)21cm for the 10 sight lines where
the value of N(H I)Lyα is not significantly affected by
geocoronal emission ranges from 0.62 and 0.91. This difference is
probably produced by a combination of systematic and random errors
and contribution from the small angular scale structure in the H I
distribution. Such structure can produce different column densities
when sampling gas with an infinitesimal beam in the UV (the angular
size of the QSO) compared to the much larger 21' beam of
the NRAO 43 m radio telescope. The overall strength of the Mg II
λλ2796 and 2803 absorption appears to be correlated with the presence
of high-velocity gas along the line to sight. Velocity-resolved Mg II
absorption associated with high-velocity gas in the Magellanic Stream
is detected toward eight QSOs, including PKS 0003+15, PG 0043+039,
PKS 0637-75, 3C 454.3, PKS 2251+11, PG 2302+029, PKS 2340-36, and
PKS 2344+09. Velocity-resolved Mg II absorption toward 15 QSOs is not
accompanied by the existence of associated H I emission. Interesting
objects in this category include PKS 0232-04 (l=174.5d, b=-56.2d),
which has a high-velocity cloud (HVC) at v~+270 km s-1
detected in Mg II, and PG 1116+215 (l=223.3d,b=68.2d) with a HVC at
+200 km s-1 detected in Mg II, C II, Si IV, and possibly
C IV. The HVC toward PKS 0232-04 is interesting because all known H I
HVCs in this general region of the sky have negative velocity rather
than positive velocity. For 15 QSOs known to lie in the direction of
H I HVCs, the Mg II lines have extremely strong principal absorption
components, suggesting the detection of blended low- and high-velocity
absorption. These lines of sight imply the detection of Mg II absorption
by the high-velocity gas in HVC complexes C and A, in the outer Galaxy
warp, and in the Magellanic Stream, as well as toward three smaller
clouds. There are 11 QSO sight lines with very strong Mg II absorption
for which there is no evidence for high-velocity H I emission. However,
six of these sight lines lie near known H I HVCs. There are 38 QSOs
with weak Mg II principal absorption and no known H I HVCs. These
objects provide information about the H I absorption characteristics of
disk and halo gas well away from H I HVCs. The sky covering factor of
high-velocity Mg II is large, with 41 and 71 QSO lines of sight showing
either resolved high-velocity Mg II absorption or principal absorption
that is so strong that blended low- and high-velocity Mg II absorption
is suggested. Based on observations with the NASA/ESA Hubble
Space Telescope, obtained at the Space Telescope Science Institute,
which is operated by the Association of Universities for Research in
Astronomy, Inc., under NASA contract NAS-26555.
Title: VizieR Online Data Catalog: HST quasar absorption-line key
project. VIII. (Kirhakos+, 1994)
Authors: Kirhakos, S.; Sargent, W. L. W.; Schneider, D. P.; Bahcall,
J. N.; Jannuzi, B. T.; Maoz, D.; Small, T. A.
Bibcode: 2000yCat..61060646K
Altcode:
We present an analysis of CCD images (obtained at the Palomar 1.5m
telescope) of more than 100 quasars; many of the objects have been
or will be observed in the HST Key Project Quasar Absorption-Line
Survey. The data set consists of B, g, and i photometry of 117
quasars and deeper g (limiting magnitude of ~22) images of 101 quasar
fields. Positions accurate to ~1", measured with the Space Telescope
Science Institute's Astrometric Support Program, are listed for all of
the quasars in this study. Positions, magnitudes, and classifications
of stars and galaxies located within ~100" of the quasars are given
for all of the deep g data. The positions of the stars and galaxies
relative to the quasar are accurate to ~0.5". The results presented
here can be used to prepare spectroscopic programs designed to obtain
redshifts of galaxies in the fields of these quasars. (3 data files).
Title: The Evolution of Neutrino Astronomy
Authors: Bahcall, John N.; Davis, Raymond, Jr.
Bibcode: 2000PASP..112..429B
Altcode: 1999astro.ph.11486B
This Essay is one of a series of invited contributions which will
appear in the PASP throughout the year 2000 to mark the upcoming
millennium. (Eds.)
Title: What will the first year of SNO show?
Authors: Bahcall, J. N.; Krastev, P. I.; Smirnov, A. Y.
Bibcode: 2000PhLB..477..401B
Altcode: 1999hep.ph...11248B
The ratio of the measured to the predicted standard model CC event
rates in SNO will be 0.47 if no oscillations occur. The best-fit active
oscillation predictions for the CC ratio are: 0.35-39 (MSW) and 0.38-42
(vacuum) (all for a /5 MeV energy threshold), typically about /20%
less than the no-oscillation expectation. We calculate the predicted
ratios for six active and sterile neutrino oscillation solutions
allowed at 99% CL and determine the dependence of the ratios on energy
threshold. If the high-energy anomaly observed by SuperKamiokande
is due to an enhanced /hep flux, MSW active solutions predict that
out of a total of /5000 CC events above /5 MeV in SNO between /49 and
/54 events will be observed above /13 MeV whereas only /19 events are
expected for no-oscillations and a nominal standard /hep flux.
Title: How Much Do Helioseismological Inferences Depend on the
Assumed Reference Model?
Authors: Basu, Sarbani; Pinsonneault, M. H.; Bahcall, John N.
Bibcode: 2000ApJ...529.1084B
Altcode: 1999astro.ph..9247B
We investigate systematic uncertainties in determining the profiles
of the solar sound speed, density, and adiabatic index using
helioseismological techniques. We find that rms uncertainties (averaged
over the Sun) of ~0.02%-0.04% are contributed to the sound-speed
profile by each of three sources: (1) the choice of assumed reference
model, (2) the width of the inversion kernel, and (3) the measurement
errors. The rms agreement between the standard solar model sound speeds
and the best helioseismological determinations is about 0.07%. The
profile of the adiabatic index, Γ1, is determined to
an accuracy of about 0.02% with the Michelson Doppler Imager (MDI)
data set. The density profile is about an order of magnitude less well
determined by the helioseismological measurements. Five state-of-the-art
models, each with a significant difference in the input physics or
a parameter choice, all give comparably good agreement with global
helioseismological measurements. We consider four deficient solar
models that are constructed either using old input data, assuming the
3He+4He fusion reaction does not occur, neglecting
element diffusion, or artificially mixing the interior of the Sun. When
used as reference models in the inversion process, these deficient
models yield sound speeds for the Sun that differ only by 0.1% from
the sound speeds obtained using the standard model. We conclude that
even relatively crude reference models yield reasonably accurate solar
parameters. Although acceptable for most purposes as reference models,
nonstandard solar models in which the core is artificially mixed or
in which element diffusion is neglected are strongly disfavored by the
p-mode oscillation data. These nonstandard models produce sound-speed
profiles with respect to the Sun that are 4.5 and 18 times worse,
respectively, than the agreement obtained with the standard solar model.
Title: Solar neutrinos
Authors: Bahcall, J. N.
Bibcode: 2000upse.conf..126B
Altcode:
No abstract at ADS
Title: Solar Neutrinos: an Overview
Authors: Bahcall, J. N.
Bibcode: 2000PhST...85...63B
Altcode:
I summarize the current state of solar neutrino research.
Title: Solar neutrinos: An overview
Authors: Bahcall, J. N.
Bibcode: 1999CSci...77.1487B
Altcode:
No abstract at ADS
Title: Ulrich's Explanation for the Solar Five Minute Oscillations
Authors: Bahcall, John
Bibcode: 1999ApJ...525C1199B
Altcode: 1999ApJC..525.1199B
No abstract at ADS
Title: Is a large mixing angle MSW effect the solution of the solar
neutrino problems?
Authors: Bahcall, J. N.; Krastev, P. I.; Smirnov, A. Yu.
Bibcode: 1999PhRvD..60i3001B
Altcode: 1999hep.ph....5220B
Recent results on solar neutrinos provide hints that the LMA
MSW solution could be correct. We perform accurate calculations
for potential ``smoking-gun'' effects of the LMA solution in
the SuperKamiokande solar neutrino experiment, including (1) an
almost constant reduction of the standard recoil electron energy
spectrum (with a weak, <10%, relative increase below 6.5 MeV),
(2) an integrated difference in day-night rates (2%-14%), (3) an
approximately constant zenith-angle dependence of the nighttime event
rate, (4) a new test for the difference in the shape of the equally
normalized day-night energy spectra (~1%), and (5) annual variations
of the signal due to the regeneration effect (~6 times smaller than
the integrated day-night effect). We also establish a relation between
the integrated day-night asymmetry and the seasonal asymmetry due to
LMA regeneration. As a cautionary example, we simulate the effect
of an absolute energy calibration error on the shape (distortion)
of the recoil energy spectrum. We compare LMA predictions with the
available SuperKamiokande data for 708 days of operation and discuss
the possibilities for distinguishing experimentally between LMA and
vacuum oscillations. If LMA is correct, global solutions combining
data from different types of measurements made by SuperKamiokande or
by different solar neutrino experiments could reveal in the next few
years a many σ indication of neutrino oscillations.
Title: The Host Galaxies of Three Radio-loud Quasars: 3C 48, 3C 345,
and B2 1425+267
Authors: Kirhakos, Sofia; Bahcall, John N.; Schneider, Donald P.;
Kristian, Jerome
Bibcode: 1999ApJ...520...67K
Altcode: 1999astro.ph..2175K
Observations with the Wide-Field/Planetary Camera-2 of the Hubble
Space Telescope are presented for three radio-loud quasars: 3C 48
(z=0.367), B2 1425+267 (z=0.366), and 3C 345 (z=0.594). All three
quasars have luminous (~4×L*) galaxies as hosts, which are
either elliptical (B2 1425+267 and 3C345) or interacting (3C 48), and
all hosts are 0.5-1.0 mag bluer in V-I than other galaxies with the same
overall morphology at redshifts similar to those of the quasars. The
host of 3C 48 has many H II regions and a very extended tidal tail. All
nine of the radio-loud quasars studied here and in a previous paper
by Bahcall et al. either have bright elliptical hosts or occur in
interacting systems. There is a robust correlation between the radio
emission of the quasar and the luminosity of host galaxy; the radio-loud
quasars reside in galaxies that are on average ~1 mag brighter than
hosts of the radio-quiet quasars. Based on observations with the
NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science
Institute, which is operated by the Association of Universities for
Research in Astronomy, Inc., under NASA contract NAS5-26555.
Title: What can we learn from past discoveries?
Authors: Bahcall, J. N.
Bibcode: 1999AAS...194.9501B
Altcode: 1999BAAS...31..992B
I will describe some ocassions during which I witnessed or talked
to people who were making important astronomical discoveries. I will
present my version of the lessons for the future that are to be learned
from these discoveries and discoverers.
Title: Standard solar models
Authors: Bahcall, John N.
Bibcode: 1999NuPhS..77...64B
Altcode: 1998astro.ph..8162B
I review recent developments that affect standard solar model
predictions of solar neutrino fluxes.
Title: How does the sun shine?
Authors: Bahcall, J. N.
Bibcode: 1999AAS...194.2701B
Altcode: 1999BAAS...31..864B
Neutrino astronomy was developed to test the theory that stars shine
and evolve by burning light elements in their interiors. Five beautiful
experiments have proven that the sun does shine by nuclear fusion
reactions, but robust discrepancies between the standard predictions
and the observations suggest that neutrinos exhibit physics beyond the
standard model of electroweak interactions. I will review the neutrino
and helioseismological evidence confirming solar fusion and suggesting
new electroweak physics. Major new observatories are being built to
search for smoking-gun evidence of non-standard neutrino phenomena.
Title: How much do helioseismological inferences depend upon the
assumed reference model?
Authors: Basu, S.; Pinsonneault, M. H.; Bahcall, J. N.
Bibcode: 1999AAS...194.5603B
Altcode: 1999BAAS...31Q.912B
We investigate systematic uncertainties in determining the profiles
of the solar sound speed and the density by helioseismological
techniques. We find that rms uncertainties averaged over the
sun ~ 0.02%-0.04% are contributed to the sound speed profile by
each of three sources: 1) the choice of assumed reference model,
2) the width of the inversion kernel, and 3) the measurement
errors. The rms agreement between the standard solar model and the
best helioseismological determinations is about 0.07%. The density
profile is about an order of magnitude less well determined by the
helioseismological measurements. JNB and SB are supported in part by
NSF grant #PHY95-13835.
Title: BSGMODEL: The Bahcall-Soneira Galaxy Model
Authors: Bahcall, John N.
Bibcode: 1999ascl.soft04001B
Altcode:
BSGMODEL is used to construct the disk and spheroid components of the
Galaxy from which the distribution of visible stars and mass in the
Galaxy is calculated. The computer files accessible here are available
for export use. The modifications are described in comment lines in
the software. The Galaxy model software has been installed and used by
different people for a large variety of purposes (see, e. g., the the
review "Star Counts and Galactic Structure'', Ann. Rev. Astron. Ap. 24,
577, 1986 ).
Title: Faint Star Counts with HST
Authors: Flynn, Chris; Gould, Andrew; Bahcall, John
Bibcode: 1999ASPC..165..387F
Altcode: 1999gaha.conf..387F; 1998astro.ph.12321F
We describe a program of star counts in the range 19 <~ I <~
26 made with the WFPC cameras aboard the Hubble Space Telescope. Red
(V-I > 1.0) stars at these magnitudes are primarily disk and spheroid
M dwarfs. The stars are found both on dedicated images as part of the
parallel program and by using appropriate archive data. We measure
the faint end of the luminosity functions of the disk and spheroid
(i.e.~stellar halo). We measure the low mass end of the mass function
and show that M dwarfs do not dominate the total disk or spheroid
mass. We place strong I band constraints on the amount of halo dark
matter in the form of low mass stars (such as M dwarfs or cool white
dwarfs). The disk and spheroid contribute only a minor amount of
optical depth toward the Magellanic clouds.
Title: Solar Neutrinos
Authors: Bahcall, J. N.
Bibcode: 1999nwap.conf...28B
Altcode:
No abstract at ADS
Title: Standard Solar Models
Authors: Bahcall, J. N.
Bibcode: 1999nenp.conf...77B
Altcode:
No abstract at ADS
Title: Prioritizing Science: A Story of the Decade Survey for
the 1990s
Authors: Bahcall, John N.
Bibcode: 1999aasf.book..289B
Altcode:
No abstract at ADS
Title: Solar Neutrinos: An Overview
Authors: Bahcall, J. N.
Bibcode: 1999ccmn.conf...37B
Altcode:
No abstract at ADS
Title: Solar Neutrinos: Where We Are
Authors: Bahcall, J.
Bibcode: 1999psc..conf....2B
Altcode:
No abstract at ADS
Title: High energy neutrinos from astrophysical sources: An upper
bound
Authors: Waxman, Eli; Bahcall, John
Bibcode: 1998PhRvD..59b3002W
Altcode: 1999PhRvD..59b3002W; 1998hep.ph....7282W
We show that cosmic-ray observations set a model-independent upper bound
of E2νΦν<2×10-8
GeV/cm2 s sr to the intensity of high-energy neutrinos
produced by photo-meson (or p-p) interactions in sources of size not
much larger than the proton photo-meson (or p-p) mean-free-path. This
bound applies, in particular, to neutrino production by either AGN
jets or GRBs. The upper limit is two orders of magnitude below the
intensity predicted in some popular AGN jet models and therefore
contradicts the theory that the cosmic gamma-ray background is due to
photo-pion interactions in AGN jets. The upper bound is consistent
with our predictions from GRB models. The predicted intensity from
GRBs is E2dN/dE~0.3×10-8 GeV/cm2
s sr for 1014 eV<E<1016 eV; we also derive
the expected intensity at higher energy.
Title: An upper bound to the high-energy neutrino flux from
astrophysical sources
Authors: Waxman, E.; Bahcall, J. N.
Bibcode: 1998tx19.confE.618W
Altcode:
An upper bound to the high-energy neutrino flux from astrophysical
sources, imposed by cosmic-ray observations, is derived. The upper
bound applies to sources which are optically thin to proton photo-meson
interaction, and cannot be avoided by invoking source redshift evolution
or inter-galactic magnetic fields. This upper limit is two orders of
magnitude below the flux predicted in popular AGN jet models, but is
consistent with our predictions from GRB models. Its implications to
future neutrino detectors are discussed.
Title: The Host Galaxy of the Gamma-Ray Burst 971214
Authors: Odewahn, S. C.; Djorgovski, S. G.; Kulkarni, S. R.; Dickinson,
M.; Frail, D. A.; Ramaprakash, A. N.; Bloom, J. S.; Adelberger, K. L.;
Halpern, J.; Helfand, D. J.; Bahcall, J.; Goodrich, R.; Frontera,
F.; Feroci, M.; Piro, L.; Costa, E.
Bibcode: 1998ApJ...509L...5O
Altcode: 1998astro.ph..7212O
We report on Hubble Space Telescope (HST) observations of the
host galaxy of GRB 971214, taken 4 months after the burst. The
redshift of the proposed host galaxy at z=3.418, combined with
optical and radio observations of the burst afterglow, implies the
extremely large isotropic energy release from the burst in γ-rays of
Eγ~3×1053 ergs, some 2 orders of magnitude
higher than the previously commonly assumed numbers. The positional
offset between the optical transient observed at the Keck telescope
and the centroid of the proposed host galaxy in the HST image is
0.14"+/-0.07". We find no evidence in our deep HST image for a chance
foreground galaxy superposed along the line of sight to the proposed
host at z=3.418. The morphology and photometric properties of this
galaxy, such as the total flux, morphology, radial surface profile,
and scale length, are typical as compared to other, spectroscopically
confirmed z>=3 galaxies. Based on observations with the
NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science
Institute, which is operated by AURA, Inc., under NASA contract NAS
5-26555 and on observations obtained at the W. M. Keck Observatory,
which is operated jointly by the California Institute of Technology
and the University of California.
Title: Where do we stand with solar neutrino oscillations?
Authors: Bahcall, J. N.; Krastev, P. I.; Smirnov, A. Yu.
Bibcode: 1998PhRvD..58i6016B
Altcode: 1998hep.ph....7216B
We determine parameters for MSW and vacuum oscillations
(active and sterile neutrinos) that are allowed by separate,
and collective, imposition of the constraints from total
event rates in the chlorine, GALLEX, SAGE, and SuperKamiokande
experiments (504 days), the SuperKamiokande energy spectrum, and
the SuperKamiokande zenith-angle dependence. The small mixing angle
MSW solution is acceptable at 7% C.L. (8% for sterile ν's) and the
vacuum solution is acceptable at 6% C.L. The best-fit global MSW
solution for active neutrinos is Δm2=5×10-6
eV2, sin22θ=5.5×10-3 (and for
sterile neutrinos Δm2=4×10-6 eV2,
sin22θ=7×10-3). For vacuum oscillations,
the best-fit solution is Δm2=6.5×10-11
eV2, sin22θ=0.75. An arbitrary combination of
undistorted (no oscillations) pp, 7Be, 8B, and
CNO neutrino fluxes is inconsistent with the combined data sets at the
3.5σ C.L., independent of astrophysical considerations. We use improved
calculations of solar model fluxes, neutrino absorption cross sections
and energy spectra, and a detailed evaluation of regeneration effects.
Title: Globular Cluster Photometry with the Hubble Space
Telescope. VII. Color Gradients and Blue Stragglers in the Central
Region of M30 from Wide Field Planetary Camera 2 Observations
Authors: Guhathakurta, Puragra; Webster, Zodiac T.; Yanny, Brian;
Schneider, Donald P.; Bahcall, John N.
Bibcode: 1998AJ....116.1757G
Altcode: 1998astro.ph..5361G
We present F555W (V), F439W (B), and F336W (U) photometry of 9507 stars
in the central 2' of the dense, post-core-collapse cluster M30 (NGC
7099) derived from Hubble Space Telescope Wide Field Planetary Camera
2 images. These data are used to study the mix of stellar populations
in the central region of the cluster. Forty-eight blue straggler stars
are identified; they are found to be strongly concentrated toward the
cluster center. The specific frequency of blue stragglers, F_BSS =
N(BSS)/N(V < V_HB + 2), is 0.25 +/- 0.05 in the inner region of
M30 (r < 20"), significantly higher than the frequency found in
other clusters: F_BSS = 0.05-0.15. The shape of M30's blue straggler
luminosity function resembles the prediction of the collisional
formation model, and is inconsistent with the binary merger model
of Bailyn & Pinsonneault. An unusually blue star (B = 18.6,
B-V = -0.97), possibly a cataclysmic variable based on its color,
is found about 1.2" from the crowded cluster center; the photometric
uncertainty for this star is large, however, because of the presence
of a very close neighbor. Bright red giant stars (B < 16.6) appear
to be depleted by a factor of 2-3 in the inner r < 10" relative
to fainter giants, subgiants, and main-sequence turnoff stars (95%
significance). We confirm that there is a radial gradient in the color
of the overall cluster light, going from B-V ~ 0.82 at r ~ 1' to B-V ~
0.45 in the central 10". The central depletion of the bright red giants
is responsible for about half of the observed color gradient; the rest
of the gradient is caused by the relative underabundance of faint red
main-sequence stars near the cluster center (presumably a result of
mass segregation). The luminosity function of M30's evolved stars does
not match the luminosity function shape derived from standard stellar
evolutionary models: the ratio of the number of bright giants to the
number of turnoff stars in the cluster is 30% higher than predicted
by the model (3.8 sigma effect), roughly independent of red giant
brightness over the range M_V = -2 to +2. Based on observations with
the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope
Science Institute, which is operated by the Association of Universities
for Research in Astronomy, Inc., under NASA contract NAS 5-26555. Lick
Observatory Bulletin No. 1377.
Title: The Hubble Space Telescope Quasar Absorption Line Key
Project. XIV. The Evolution of Lyα Absorption Lines in the Redshift
Interval z = 0-1.5
Authors: Weymann, Ray J.; Jannuzi, Buell T.; Lu, Limin; Bahcall,
John N.; Bergeron, Jacqueline; Boksenberg, Alec; Hartig, George F.;
Kirhakos, Sofia; Sargent, W. L. W.; Savage, Blair D.; Schneider,
Donald P.; Turnshek, David A.; Wolfe, Arthur M.
Bibcode: 1998ApJ...506....1W
Altcode: 1998astro.ph..6123W
We present the results of an analysis of the rate of evolution of the
Lyα absorption lines in the redshift interval 0.0 to ~1.5 based upon
a sample of 987 Lyα absorption lines identified in the spectra of 63
QSOs obtained with the Faint Object Spectrograph (FOS) of the Hubble
Space Telescope (HST). These spectra were obtained as part of the QSO
Absorption Line Survey, an HST Key Project during the first four years
of observations with the telescope. Fits to the evolution of the number
of absorbers per unit redshift (dN/dz) of the form dN/dz = A × (1 +
z)γ continue to yield values of γ in the range 0.1-0.3,
decidedly flatter than results from ground-based data pertaining
to the redshift range z > 1.7. These results are consistent with
our previous results based on a much smaller sample of lines, but the
uncertainties in the fit have been greatly reduced. The combination of
the HST and ground-based data suggest a marked transition in the rate
of evolution of the Lyα lines at a redshift of about 1.7. The 19 Lyα
lines from an additional higher redshift QSO from our sample for which
tentative line identifications are available (UM 18; zem
= 1.89) support the suggestion of a rapid increase at around this
redshift. We derive the cumulative distribution of the full sample of
Lyα lines and show that the distribution in redshift can indeed be
well represented by a power law of the form (1 + z)γ. For
this same sample, the distribution of equivalent widths of the Lyα
absorbers above a rest equivalent width of 0.1 Å is fit quite well
by an exponential. Comparing samples of Lyα lines, one set of which
has redshifts the same as, or very near to, the redshifts of ions from
heavy elements and another set in which no ions from heavy elements
have been identified, we find that the Lyα systems with heavy element
detections have a much steeper slope than the high rest equivalent
width portion of the Lyman-only sample. We argue that this result is
not likely to be due to either line misidentification or incomplete
spectral coverage. Considering the insensitivity of the equivalent width
to large changes in the column density for saturated lines, we suggest
that this result is probably attributable to rapid evolution of the
very highest column density systems, rather than real differences in
metallicity. We find evidence that the rate of evolution increases with
increasing equivalent width. We compare our results for the variation
of line density with redshift to recent numerical simulations of Lyα
absorbers, in particular, to those of Riediger, Petitjean, & Mucket,
which extend to zero redshift. We find fairly good agreement between
these simulations and our results, though the rapid evolution we find
in the Lyα systems containing heavy element ions is not predicted
in their models. We speculate that these heavy element-containing
Lyα systems involve those clouds closely associated with galaxies,
whose column densities are too high and whose sizes are too small to be
included in the Riediger et al. simulations. Our results for Lyα lines
at the high end of our equivalent width distribution are compatible
with the recent analysis of the absorber-galaxy correlation by Chen et
al. For the weaker lines, however, our results suggest that whatever
association exists between absorbers and galaxies is different from that
for the stronger lines. We conclude with some suggestions for further
observations. Based on observations with the NASA/ESA Hubble
Space Telescope, obtained at the Space Telescope Science Institute,
which is operated by the Association of Universities for Research in
Astronomy, Inc., under NASA contract NAS 5-26555.
Title: Solar fusion cross sections
Authors: Adelberger, Eric G.; Austin, Sam M.; Bahcall, John N.;
Balantekin, A. B.; Bogaert, Gilles; Brown, Lowell S.; Buchmann, Lothar;
Cecil, F. Edward; Champagne, Arthur E.; de Braeckeleer, Ludwig; Duba,
Charles A.; Elliott, Steven R.; Freedman, Stuart J.; Gai, Moshe;
Goldring, G.; Gould, Christopher R.; Gruzinov, Andrei; Haxton,
Wick C.; Heeger, Karsten M.; Henley, Ernest; Johnson, Calvin W.;
Kamionkowski, Marc; Kavanagh, Ralph W.; Koonin, Steven E.; Kubodera,
Kuniharu; Langanke, Karlheinz; Motobayashi, Tohru; Pandharipande,
Vijay; Parker, Peter; Robertson, R. G.; Rolfs, Claus; Sawyer, R. F.;
Shaviv, N.; Shoppa, T. D.; Snover, K. A.; Swanson, Erik; Tribble,
Robert E.; Turck-Chièze, Sylvaine; Wilkerson, John F.
Bibcode: 1998RvMP...70.1265A
Altcode: 1998astro.ph..5121A
We review and analyze the available information on the nuclear-fusion
cross sections that are most important for solar energy generation and
solar neutrino production. We provide best values for the low-energy
cross-section factors and, wherever possible, estimates of the
uncertainties. We also describe the most important experiments and
calculations that are required in order to improve our knowledge of
solar fusion rates.
Title: Screening in Thermonuclear Reaction Rates in the Sun
Authors: Gruzinov, Andrei V.; Bahcall, John N.
Bibcode: 1998ApJ...504..996G
Altcode: 1998astro.ph..1028G
We evaluate the effect of electrostatic screening by ions and electrons
on low-Z thermonuclear reactions in the Sun. We use a mean field
formalism and calculate the electron density of the screening cloud
using the appropriate density matrix equation of quantum statistical
mechanics. Because of well-understood physical effects that are included
for the first time in our treatment, the calculated enhancement of
reaction rates does not agree with the frequently used interpolation
formulae. Our result does agree, within small uncertainties, with
Salpeter's weak screening formula. If weak screening is used instead
of the commonly employed screening prescription of Graboske et al.,
the predicted 8B neutrino flux is increased by 7% and the
predicted chlorine rate is increased by 0.4 SNU.
Title: The Hubble Space Telescope Quasar Absorption Line Key
Project. XIII. A Census of Absorption-Line Systems at Low Redshift
Authors: Jannuzi, Buell T.; Bahcall, John N.; Bergeron, Jacqueline;
Boksenberg, Alec; Hartig, George F.; Kirhakos, Sofia; Sargent,
W. L. W.; Savage, Blair D.; Schneider, Donald P.; Turnshek, David A.;
Weymann, Ray J.; Wolfe, Arthur M.
Bibcode: 1998ApJS..118....1J
Altcode: 1998astro.ph..5148J
We present a catalog of absorption lines obtained from the analysis
of the ultraviolet spectra of 66 quasars. The data were acquired with
the Faint Object Spectrograph of the Hubble Space Telescope (HST)
as part of the Quasar Absorption Line Survey, a Key Project for the
first four cycles of HST observations. This is the third of a series
of catalogs of absorption lines produced from the survey and increases
the number of quasars whose higher resolution (R = 1300) spectra we
have published from 17 to 83. The general properties and execution of
the survey are reviewed, including descriptions of the final sample
of observed objects and the algorithmic processes used to construct
the catalog. This database is suitable for a wide variety of studies
of gaseous systems in the nearby universe. This third catalog includes
2594 absorption lines and brings the total number of absorption lines in
the combined catalog to 3238. The third catalog has 878 identified Lyα
lines, 27 extensive metal line systems (detected absorption lines from
four or more metal ions), 88 C IV systems, and 34 O VI systems. The
combined catalog contains the following numbers of extragalactic
absorption lines: 1129 Lyα lines, 107 C IV systems, 41 O VI systems,
16 Lyman limit systems, and one damped Lyα system (in the spectrum
of PG 0935+416). In addition, there are 25 pairs of identified Lyα
lines that are candidate C IV doublets. Of the 122 identified C IV and
candidate C IV systems in the completely identified sample of absorption
lines, 24 +/- 5 are expected to be chance coincidences of other lines
(based upon Monte Carlo simulations). The detection of a single damped
Lyα system in a path length of Δz = 49 yields an observed number of
damped systems per unit redshift of (dN/dz)damp(z = 0.58)
= 0.020 with 95% confidence boundaries of 0.001-0.096 systems per unit
redshift. We include notes on our analysis of each of the observed
quasars and the absorption systems detected in each spectrum. Some
especially interesting systems include low-redshift Lyα absorbers
suitable for extensive follow-up observations (e.g., in the spectra
of TON 28 and PG 1216+069), possibly physically associated pairs of
extensive metal line absorption systems (e.g., in the spectrum of PG
0117+213), and systems known to be associated with galaxies (e.g.,
in the spectrum of 3C 232). The spectra of five broad absorption
line (BAL) quasars (UM 425, PG 1254+047, PG 1411+442, PG 1700+518, and
PG 2112+059) can be found in this third catalog, bringing the total
number of BAL quasars in the combined catalog to six (including PG
0043+039). Based on observations with the NASA/ESA Hubble Space
Telescope, obtained at the Space Telescope Science Institute, which is
operated by the Association of Universities for Research in Astronomy,
Inc., under NASA contract NAS 5-26555.
Title: Do hep neutrinos affect the solar neutrino energy spectrum?
Authors: Bahcall, John N.; Krastev, Plamen I.
Bibcode: 1998PhLB..436..243B
Altcode: 1998hep.ph....7525B
If the low energy cross section for
3He+p-->4He+e++νe, the
`hep' reaction, is >~20 times larger than the best (but uncertain)
theoretical estimates, then this reaction could significantly influence
the electron energy spectrum produced by solar neutrino interactions
and measured in the SuperKamiokande, SNO, and ICARUS experiments. We
compare predicted energy spectra for different assumed hep fluxes
and different neutrino oscillation scenarios with the observed
SuperKamiokande spectrum. The spectra with enhanced hep contributions
provide better fits to the SuperKamiokande data.
Title: Spheroid Luminosity and Mass Functions from Hubble Space
Telescope Star Counts
Authors: Gould, Andrew; Flynn, Chris; Bahcall, John N.
Bibcode: 1998ApJ...503..798G
Altcode: 1997astro.ph.11263G
We analyze 166 spheroid subdwarfs (6.5 < MV < 14.5)
found in 53 fields observed with the Wide Field Planetary Camera on
the Hubble Space Telescope. The fields cover 221 arcmin2
over a wide range of directions. The spheroid luminosity function (LF)
is inconsistent at about the 3 σ level with the local spheroid LF of
Dahn et al. even when the normalization of the latter is corrected to
take account of the latest data on spheroid kinematics. The difference
may reflect systematic errors in one of the two studies or features
of the spheroid spatial distribution that are not included in the
simplest models. The mass function, which shows no obvious structure,
can be represented by a power law, dN/d ln M ~ Mα, with
α = 0.25 +/- 0.32 over the mass range 0.71 M⊙ > M
> 0.09 M⊙. The spheroid therefore does not contribute
significantly to microlensing unless the mass function changes slope
dramatically in the substellar range. The total local mass density
of spheroid stars (including remnants and unseen binary companions)
is ρ ~ 6.4 × 10-5 M⊙ pc-3, with
an uncertainty of about 50%. The power-law indices α = 0.25 for the
spheroid and α = 0.44 for the disk (both uncorrected for binaries) are
similar to those of globular clusters of moderate-to-high metallicity.
Title: Electron-screening correction for the proton-proton reaction
Authors: Bahcall, John N.; Chen, Xuelei; Kamionkowski, Marc
Bibcode: 1998PhRvC..57.2756B
Altcode: 1996astro.ph.12209B
We test the Salpeter formalism for the electron screening of the solar
proton-proton fusion reaction by solving numerically the relevant
Schrödinger equation. We evaluate exactly the square of the overlap
integral of the two-proton wave function and the deuteron wave function
and compare with the usual analytic approximation. The usual WKB
solution agrees with the numerical result to O(10-4). The
WKB approximation should be even more precise for the other nuclear
fusion reactions in the pp chain and CNO cycles.
Title: Hans Bethe Prize Recipient: Solar Neutrinos: from Darwin to
Bethe to Superkamiokande and SNO
Authors: Bahcall, John
Bibcode: 1998APS..APR..I104B
Altcode:
The nineteenth century debate on the origin of stellar energy
generation was resolved theoretically by Hans Bethe in the late
1930's and experimentally by Ray Davis in the 1970's. Kamiokande
showed conclusively in the 1990s that the observed neutrinos come
from the sun. Five beautiful experiments (chlorine, Kamiokande,
GALLEX, SAGE, and Superkamiokande) have by now detected solar
neutrinos, which have approximately the fluxes and energies
predicted by calculations of nuclear fusion rates in standard solar
models. Quantitative discrepancies between the standard model
predictions (which assume that nothing happens to the neutrinos
after they are created) and the measurements provide evidence that
physics beyond the standard electroweak model may be manifested in
solar neutrino experiments. Recent helioseismological measurements
strengthen this inference. I will summarize the current status of <A
HREF=http://www.sns.ias.edu/ jnb/>solar neutrino research</A>
and review the prospects for discovering ``smoking-gun'' evidence for
new physics with the Superkamiokande, SNO, and BOREXINO detectors.
Title: Solar neutrinos: where we are, what we need
Authors: Bahcall, John
Bibcode: 1998NuPhA.631...29B
Altcode: 1998nucl.th...2050B
This talk compares standard model predictions for solar neutrino
experiments with the results of actual observations. Here `standard
model' means the combined standard model of minimal electroweak
theory plus a standard solar model. I emphasize the importance of
recent analyses in which the neutrino fluxes are treated as free
parameters, independent of any constraints from solar models, and
the stunning agreement between the predictions of standard solar
models and helioseismological measurements. In order to interpret
solar neutrino experiments more accurately in terms of fundamental
physics and astronomy, we need improved improved nuclear physics
data. I describe the five most important nuclear physics problems
whose solution is required for understanding the precise implications
of solar neutrino experiments. Relevant preprints and references
to other solar neutrino papers, as well as links to solar neutrino
experiments, software, and numerical data are available at my Web site:
http://www.sns.ias.edu/~jnb. This Web site also contains a series of
solar neutrino viewgraphs, with explanations, that can be downloaded.
Title: How uncertain are solar neutrino predictions?
Authors: Bahcall, John N.; Basu, Sarbani; Pinsonneault, M. H.
Bibcode: 1998PhLB..433....1B
Altcode: 1998astro.ph..5135B; 1998PhLB..433..128B
Solar neutrino fluxes and sound speeds are calculated using a systematic
reevaluation of nuclear fusion rates. The largest uncertainties are
identified and their effects on the solar neutrino fluxes are estimated.
Title: Solar Neutrinos: Where We Are
Authors: Bahcall, J.
Bibcode: 1998tsra.conf...99B
Altcode: 1997astro.ph..2057B
This talk compares standard model predictions for solar neutrino
experiments with the results of actual observations. Here `standard
model' means the combined standard model of minimal electroweak
theory plus a standard solar model. I emphasize the importance of
recent analyses in which the neutrino fluxes are treated as free
parameters, independent of any constraints from solar models, and the
stunning agreement between the predictions of standard solar models
and helioseismological measurements.
Title: Gallium solar neutrino experiments: Absorption cross sections,
neutrino spectra, and predicted event rates
Authors: Bahcall, John N.
Bibcode: 1997PhRvC..56.3391B
Altcode: 1997hep.ph...10491B
Neutrino absorption cross sections for 71Ga are calculated
for all solar neutrino sources with standard energy spectra, and
for laboratory sources of 51Cr and 37Ar; the
calculations include, where appropriate, the thermal energy of fusing
solar ions and use improved nuclear and atomic data. The ratio, R, of
measured (in GALLEX and SAGE) to calculated 51Cr capture rate
is R=0.95+/-0.07 (expt)++0.04-0.03 (theor). Cross
sections are also calculated for specific neutrino energies chosen so
that a spline fit determines accurately the event rates in a gallium
detector even if new physics changes the energy spectrum of solar
neutrinos. Theoretical uncertainties are estimated for cross sections
at specific energies and for standard neutrino energy spectra. Standard
energy spectra are also presented for pp and CNO neutrino sources in the
appendix. Neutrino fluxes predicted by standard solar models, corrected
for diffusion, have been in the range 120 SNU to 141 SNU since 1968.
Title: The Standard Solar Model
Authors: Bahcall, John
Bibcode: 1997snns.confE...1B
Altcode:
No abstract at ADS
Title: Space Interferometry: the Next Frontier?
Authors: Bahcall, J. N.
Bibcode: 1997AAS...191.2301B
Altcode: 1997BAAS...29.1249B
The Decade Survey for Astronomy and Astrophysics in the 1990s
recommended the development of an interferometric mission to
``...achieve a 1000 fold improvement in our ability to measure
celestial positions.'' The design goal was to measure positions of
widely separated objects to visual magnitude 20 with an accuracy of
30 microarcseconds. Our futuristic hope was that the mission might
achieve 3 microacrseconds. The design concept adopted by the NASA
for the Space Interferometry Mission (SIM) brilliantly fulfills these
scientific goals. The precision provided by SIM promises to open up
a vast new frontier of scientific problems.
Title: What Have We Learned from the Decade Survey for the 1990s?
Authors: Bahcall, J.
Bibcode: 1997AAS...191.6101B
Altcode: 1997BAAS...29.1308B
I will summarize the principal lessons that we learned in carrying
out the Decade Survey for the 1990s and describe the most important
objectives that were (or were not) achieved.
Title: Gallium solar neutrino experiments
Authors: Bahcall, J.
Bibcode: 1997AAS...191.2601B
Altcode: 1997BAAS...29.1253B
Neutrino absorption cross sections for (71Ga) are calculated for
all solar neutrino sources with standard energy spectra, and for
laboratory sources of (51Cr) and (37Ar) ; the calculations include,
where appropriate, the thermal energy of decaying solar ions and
use improved nuclear and atomic data. The ratio, R, of measured
(in GALLEX and SAGE) to calculated (51Cr) capture rate is R = 0.95
+/- 0.07 (exp) + (+0.04}_{-0.03) (theory). Cross sections are also
calculated for specific neutrino energies chosen so that a spline fit
determines accurately the event rates in a gallium detector even if new
physics changes the energy spectrum of solar neutrinos. Theoretical
uncertainties are estimated for cross sections at specific energies
and for standard neutrino energy spectra. Standard energy spectra are
presented for pp and CNO neutrino sources in the appendices. Neutrino
fluxes predicted by standard solar models, and minimal standard
electroweak theory, when corrected for diffusion, have been in the range
120 SNU to 141 SNU since 1968. The measured rate is 70.5 +/- 7 SNU.
Title: Solar Neutrinos: News About SNUs
Authors: Bahcall, J.; Haxton, W.; Langacker, P.; Robertson, H.;
Totsuka, Y.
Bibcode: 1997snns.conf.....B
Altcode:
No abstract at ADS
Title: An Introduction To Solar Neutrino Research
Authors: Bahcall, John
Bibcode: 1997hep.ph...11358B
Altcode:
The first lecture describes the conflicts between the combined
standard model (minimal electroweak and solar) predictions and the
results of solar neutrino experiments. The second lecture discusses
the possibilities for detecting with solar neutrinos ``smoking gun''
indications of departures from minimal electroweak theory. Viewgraphs
and related data are available at http://www.sns.ias.edu/~jnb .
Title: Does the Sun appear brighter at night in neutrinos?
Authors: Bahcall, J. N.; Krastev, P. I.
Bibcode: 1997PhRvC..56.2839B
Altcode: 1997hep.ph....6239B
We calculate accurately the number of solar neutrino events expected
as a function of solar zenith angle, with and without neutrino
oscillations, for detectors at the locations of Super-Kamiokande, SNO,
and the Gran Sasso National Laboratory. Using different Earth models
to estimate geophysical uncertainties, and different solar models to
estimate solar uncertainties, we evaluate distortions predicted by
the Mikheyev-Smirnov-Wolfenstein (MSW) effect in the zenith angle
distributions of solar neutrino events. The distortions are caused
by oscillations and by ν-e interactions in the Earth that regenerate
νe from νμ or ντ. We show that the
first two moments of the zenith-angle distribution are more sensitive
to the small mixing angle MSW solution than the conventionally studied
day-night asymmetry. We present iso-σ contours that illustrate the
potential of Super-Kamiokande, SNO, BOREXINO, ICARUS, and HERON/HELLAZ
for detecting the Earth regeneration effect at their actual locations
(and at the equator). MSW solutions favored by the four pioneering
solar neutrino experiments predict characteristic distortions for
Super-Kamiokande, SNO, BOREXINO, and ICARUS that range from being
unmeasurably small to >5σ (stat) after only a few years of
observations.
Title: The 7Be Electron Capture Rate in the Sun
Authors: Gruzinov, Andrei V.; Bahcall, John N.
Bibcode: 1997ApJ...490..437G
Altcode: 1997astro.ph..2065G
For solar conditions, we numerically integrate the density matrix
equation for a thermal electron in the field of a 7Be ion
and other plasma ions and smeared-out electrons. With this technique, we
can calculate the capture rate without either assuming the existence of
bound states or requiring fluctuations to be spherical. Our results
are in agreement with previous calculations that are based on a
different physical picture, a picture that postulates the existence of
distinct continuum and bound-state orbits for electrons. The density
matrix calculation of the electron capture rate is independent of the
nature of electron states in the solar plasma. To within 1% accuracy,
the effects of screening can be described at high temperatures by a
Salpeter-like factor of exp (-Ze2/kTRD), which can
be derived from the density matrix equation. We show that nonspherical
fluctuations change the reaction rate by less than 1%. The total
theoretical uncertainty in the electron capture rate is about +/-2%.
Title: ^8B Solar Neutrinos
Authors: Bahcall, John N.
Bibcode: 1997APS..DNP..BB01B
Altcode:
Solar neutrino astronomy began because of the expectation that the
^8B neutrino flux from the Sun is large enough to be measured at the
Earth. The newest neutrino detectors, Super-Kamiokande and the soon
to be commissioned SNO detector, will make a detailed study of the
energy spectrum of ^8B neutrinos. In this talk, I will review the
status of the solar neutrino problems and then focus on the state of
our knowledge about the critical part of the solar neutrino spectrum
coming from ^8B decay.
Title: Obituaries: Lyman Spitzer, Jr.
Authors: Bahcall, John N.; Ostriker, Jeremiah P.
Bibcode: 1997PhT....50j.123B
Altcode:
No abstract at ADS
Title: Localized Helioseismic Constraints on Solar Structure
Authors: Bahcall, John N.; Basu, Sarbani; Kumar, Pawan
Bibcode: 1997ApJ...485L..91B
Altcode: 1997astro.ph..2075B
Localized differences between the real Sun and standard solar models
are shown to be small. The sound speeds of the real and the standard
model Suns typically differ by less than 0.3% for regions of radial
width ~=0.1 Rsolar in the solar core.
Title: M Dwarfs from Hubble Space Telescope Star Counts. III. The
Groth Strip
Authors: Gould, Andrew; Bahcall, John N.; Flynn, Chris
Bibcode: 1997ApJ...482..913G
Altcode: 1996astro.ph.11157G
We analyze the disk M dwarfs found in 31 new fields observed with
the Wide Field Camera 2 (WFC2) on the Hubble Space Telescope,
together with the sample previously analyzed from 22 WFC2 fields
and 162 prerepair Planetary Camera 1 fields. The new observations,
which include the 28 high-latitude fields comprising the Large Area
Multi-Color Survey (Groth Strip), increase the total sample to 337
stars, and more than double the number of late M dwarfs (MV
> 13.5) from 23 to 47. The mass function changes slope at M ~
0.6 M⊙, from a near-Salpeter power-law index of α =
-1.21 to α = 0.44. In both regimes, the mass function at the Galactic
plane is given by (d2N)/(d log MdV)=8.1×10-2
pc-3(M/(0.59 Msolar))α . The
correction for secondaries in binaries changes the low-mass index
from α = 0.44 to α ~ 0.1. If the Salpeter slope continued to the
hydrogen-burning limit, we would expect 500 stars in the last four
bins (14.5 < MV < 18.5), instead of the 25 actually
detected. The explanation of the observed microlensing rate toward the
Galactic bulge requires either a substantial population of bulge brown
dwarfs or that the disk and bulge mass functions are very different
for stars with M <~ 0.5 M⊙.
Title: Hubble Space Telescope Images of a Sample of 20 Nearby
Luminous Quasars
Authors: Bahcall, John N.; Kirhakos, Sofia; Saxe, David H.; Schneider,
Donald P.
Bibcode: 1997ApJ...479..642B
Altcode: 1996astro.ph.11163B
Observations with the Wide-Field Camera of the Hubble Space Telescope
(HST) are presented for a representative sample of 20 intrinsically
luminous quasars with redshifts smaller than 0.30. These observations
show that luminous quasars occur in diverse environments that include
ellipticals as bright as the brightest cluster galaxies (two),
apparently normal ellipticals (10), apparently normal spirals with H
II regions (three), complex systems of gravitationally interacting
components (three), and faint surrounding nebulosity (two). The
quasar host galaxies are centered on the quasar to the accuracy of our
measurements, 400 pc. There are more radio-quiet quasars in galaxies
that appear to be ellipticals (seven) than in spiral hosts (three),
contrary to expectations. However, three, and possibly five, of the
six radio-loud quasars have detectable elliptical hosts, in agreement
with expectations. The luminous quasars studied in this paper occur
preferentially in luminous galaxies. The average absolute magnitude
of the hosts is 2.2 mag brighter than expected for a field galaxy
luminosity function. The superb optical characteristics of the
repaired HST make possible the detection of close galactic companions;
we detect eight companion galaxies within projected distances of 10
kpc from quasar nuclei. The presence of very close companions, the
images of current gravitational interactions, and the higher density of
galaxies around the quasars suggest that gravitational interactions
play an important role in triggering the quasar phenomenon. Based on observations with the NASA/ESA Hubble Space Telescope,
obtained at the Space Telescope Science Institute, which is operated
by the Association of Universities for Research in Astronomy, Inc.,
under NASA contract NAS 5-26555.
Title: Prioritizing Science: A Story of the Decade Survey for
the 1990s
Authors: Bahcall, John N.
Bibcode: 1997astro.ph..4255B
Altcode:
This article summarizes the process by which astronomers and
astrophysicists reached a consensus view as to what are the highest
priority scientific projects for the decade of the 1990s. I also review
the remarkable success of these recommendations.
Title: Recent Highlights of Hubble Space Telescope Observations
Authors: Bahcall, John
Bibcode: 1997APS..APR..C601B
Altcode:
No abstract at ADS
Title: High Energy Neutrinos from Cosmological Gamma-Ray Burst
Fireballs
Authors: Waxman, Eli; Bahcall, John
Bibcode: 1997PhRvL..78.2292W
Altcode: 1997astro.ph..1231W
Observations suggest that γ-ray bursts (GRBs) are produced by the
dissipation of the kinetic energy of a relativistic fireball. We show
that a large fraction, >=10%, of the fireball energy is expected to
be converted by photomeson production to a burst of ~1014
eV neutrinos. A km2 neutrino detector would observe at
least several tens of events per year correlated with GRBs, and test
for neutrino properties (e.g., flavor oscillations, for which upward
moving τ's would be a unique signature, and coupling to gravity) with
an accuracy many orders of magnitude better than is currently possible.
Title: The proton-proton reaction, solar neutrinos, and a relativistic
field theoretic model of the deuteron
Authors: Bahcall, John N.; Kamionkowski, Marc
Bibcode: 1997NuPhA.625..893B
Altcode: 1997astro.ph..7320B
In a series of recent papers, Ivanov et al. and Oberhummer et
al. have calculated the rate for the p + p -> d + e+
+ ve reaction with a zero-range four-fermion effective
interaction and find a result 2.9 times higher than the standard value
calculated from non-relativistic potential theory. Their procedure
is shown to give a wrong answer because their assumed interaction
disagrees with low-energy pp scattering data.
Title: Globular Cluster Photometry with the Hubble Space
Telescope.VI.WF/PC-I Observations of the Stellar Populations in the
Core of M13 (NGC 6205)
Authors: Cohen, Randi L.; Guhathakurta, Puragra; Yanny, Brian;
Schneider, Donald P.; Bahcall, John N.
Bibcode: 1997AJ....113..669C
Altcode: 1996astro.ph.11151C
We study the dense core of the globular cluster Messier 13 (NGC 6205)
using pre-refurbishment Planetary Camera-I images obtained with the
Hubble Space Telescope. Short exposures (60 s) through the F555W and
F785LP filters (similar to Johnson V and I, respectively) have been used
to obtain V and I photometry of 2877 stars brighter than V ~ 20 in a
1.25 arcmin(2) region of the cluster including its core and extending
out to r ~ 66('') (2.3 pc) from its center. The sample is complete to
V =~ 18.3 (the main sequence turnoff) and the 1sigma photometric error
is about 0.1 mag. We find 15 blue straggler star candidates and 10 other
possible blue stragglers in this region of M13. Their specific frequency
is in the range F_BSS=0.04-0.07, comparable to what is observed near the
centers of other dense clusters. A comparison between M13's observed
V band stellar luminosity function and a theoretical model (Bergbusch
& Vandenberg 1992) for the luminosity function of an old, metal-poor
cluster shows that the model predicts too few of the brightest red
giants (V ~ 12.5-15) by a factor of two relative to subgiants/turnoff
stars (>6sigma effect). The radial distributions of the red giants,
blue stragglers, and subgiants are consistent with one another, and
are well fit by a King profile of core radius r_core=38(''}+/-6({''))
(90% confidence limits) or 1.3 pc. Stars in the blue horizontal branch
of M13, however, appear to be centrally depleted relative to other
stellar types. We combine data from three dense `King model clusters',
M13, M3, and 47 Tuc, and two post core collapse clusters, M30 and M15,
and compare the distributions of various stellar types as a function
of (r/r_half light) and (r/r_core). The horizontal branch stars in the
combined sample appear to be centrally depleted relative to the giants
(97% significance)--this depletion is only a 1sigma -2sigma effect in
each of the clusters taken individually. The blue stragglers in the
combined sample are centrally concentrated relative to the giants.
Title: What can be learned by measuring the fluxes of the
7Be and the pep solar neutrino lines?
Authors: Bahcall, J. N.; Krastev, P. I.
Bibcode: 1997PhRvC..55..929B
Altcode: 1996astro.ph..7013B
Measurements of the interaction rates of the solar neutrino lines
of 7Be and pep can be used, independent of solar models,
to test whether electron flavor is conserved, to determine survival
probabilities of electron-type neutrinos at specific energies,
and to test for the existence of sterile neutrinos. We present
analytic descriptions of these tests. We also illustrate by numerical
simulations, assuming matter-enhanced and vacuum neutrino oscillations,
what measurements of solar neutrino lines can teach us about neutrino
masses and mixing angles.
Title: Are Standard Solar Models Reliable?
Authors: Bahcall, John N.; Pinsonneault, M. H.; Basu, Sarbani;
Christensen-Dalsgaard, J.
Bibcode: 1997PhRvL..78..171B
Altcode: 1996astro.ph.10250B
The sound speeds of solar models that include element diffusion
agree with helioseismological measurements to a rms discrepancy
of better than 0.2% throughout almost the entire Sun. Models that
do not include diffusion, or in which the interior of the Sun is
assumed to be significantly mixed, are effectively ruled out by
helioseismology. Standard solar models predict the measured properties
of the Sun more accurately than is required for applications involving
solar neutrinos.
Title: Neutrino oscillations and moments of electron spectra
Authors: Bahcall, J. N.; Krastev, P. I.; Lisi, E.
Bibcode: 1997PhRvC..55..494B
Altcode: 1996nucl.ex..10010B
We show that the effects of neutrino oscillations on 8B solar
neutrinos are described well by the first two moments (the average
and the variance) of the energy distribution of scattered or recoil
electrons. For the SuperKamiokande and the Sudbury Neutrino Observatory
experiments, the differences between the moments calculated with
oscillations and the standard, no-oscillation moments are greater than
three standard deviations for a significant fraction of the neutrino
mass-mixing (Δm2,sin22θ) parameter space.
Title: HST Images of Twenty Nearby Luminous Quasars
Authors: Bahcall, J. N.; Kirhakos, S.; Schneider, D. P.
Bibcode: 1997quho.conf...37B
Altcode: 1996quho.conf...37B
No abstract at ADS
Title: Solar neutrinos: solved and unsolved problems.
Authors: Bahcall, J. N.
Bibcode: 1997upa..conf..195B
Altcode:
This paper answers a series of questions. Why study solar
neutrinos? What does the combined standard model (solar plus
electroweak) predict for solar neutrinos? Why are the calculations of
neutrino fluxes robust? What are the three solar neutrino problems? What
have we learned in the first 30 years of solar neutrino research? For
the next decade, what are the most important solvable problems in
the physics of solar neutrinos? What are the most important solvable
problems in the astrophysics of solar neutrinos?
Title: Hubble Space Telescope Images of a Sample of Twenty Nearby
Luminous Quasars
Authors: Bahcall, J. N.; Kirhakos, S.; Saxe, D. H.; Schneider, D. P.
Bibcode: 1997hsth.conf..387B
Altcode:
No abstract at ADS
Title: Unsolved Problems in Astrophysics
Authors: Bahcall, John N.; Ostriker, Jeremiah P.
Bibcode: 1997upa..conf.....B
Altcode:
No abstract at ADS
Title: How well do standard solar models describe the results of
solar neutrino experiments?
Authors: Bahcall, J. N.
Bibcode: 1997MmSAI..68..361B
Altcode: 1996astro.ph..6161B
The neutrino fluxes calculated from the 14 standard solar models
published recently in refereed journals are inconsistent with the
results of the 4 pioneering solar neutrino experiments if nothing
happens to the neutrinos after they are created in the solar
interior. The calculated fluxes and the experimental results are in
good agreement if neutrino oscillations occur.
Title: Is H_0 Well Defined?
Authors: Bahcall, John N.
Bibcode: 1996PASP..108.1097B
Altcode:
As moderator, I very much enjoyed the high level of scientific
discussion and wondered if the residual disagreement might be caused
by different operational definitions of H_0. (SECTION: A Debate on
The Scale of the Universe)
Title: Helioseismology, Solar Models, and Solar Neutrinos
Authors: Bahcall, J. N.; Pinsonneault, M. H.
Bibcode: 1996AAS...189.5601B
Altcode: 1996BAAS...28.1346B
We compare with helioseismological measurements the sound speeds
computed from solar models that we have developed to calculate
solar neutrino fluxes. The agreement is spectacularly good throughout
essentially the entire sun. Solar models that do not include diffusion,
or in which the interior of the sun is assumed to be significantly
mixed, are ruled out by helioseismology. Standard solar models predict
the measured properties of the sun more accurately than is required
for applications involving solar neutrinos. These results strengthen
the case that the discrepancies between observed and predicted solar
neutrino fluxes are due to new physics.
Title: Tests of electron flavor conservation with the Sudbury
Neutrino Observatory
Authors: Bahcall, John N.; Lisi, Eligio
Bibcode: 1996PhRvD..54.5417B
Altcode: 1996hep.ph....7433B
We analyze tests of electron flavor conservation that can be performed
at the Sudbury Neutrino Observatory (SNO). These tests, which utilize
8B solar neutrinos interacting with deuterium, measure
(1) the shape of the recoil electron spectrum in charged-current (CC)
interactions (the CC spectrum shape), and (2) the ratio of the number
of charged-current to neutral current (NC) events (the CC/NC ratio). We
determine standard model predictions for the CC spectral shape and for
the CC/NC ratio, together with realistic estimates of their errors and
the correlations between errors. We consider systematic uncertainties
in the standard neutrino spectrum and in the charged-current and
neutral current cross sections, the SNO energy resolution and absolute
energy scale, and the SNO detection efficiencies. Assuming that either
matter-enhanced or vacuum neutrino oscillations solve the solar neutrino
problems, we calculate the confidence levels with which electron flavor
nonconservation can be detected using either the CC spectrum shape or
the CC/NC ratio, or both. If the SNO detector works as expected, the
neutrino oscillation solutions that best fit the results of the four
operating solar neutrino experiments can be distinguished unambiguously
from the standard predictions of electron flavor conservation.
Title: Status of Solar Models
Authors: Bahcall, John N.; Pinsonneault, Marc H.
Bibcode: 1996hep.ph...10542B
Altcode:
The neutrino fluxes calculated from 14 standard solar models published
recently in refereed journals are inconsistent with the results of
the 4 pioneering solar neutrino experiments if nothing happens to the
neutrinos after they are created in the solar interior. The sound speeds
calculated from standard solar models are in excellent agreement with
helioseismological measurements of sound speeds. Some statements made
by Dar at Neutrino 96 are answered here.
Title: The Hubble Space Telescope Quasar Absorption Line Key
Project: The Unusual Absorption-Line System in the Spectrum of PG
2302+029---Ejected or Intervening?
Authors: Jannuzi, B. T.; Hartig, G. F.; Kirhakos, S.; Sargent,
W. L. W.; Turnshek, D. A.; Weymann, R. J.; Bahcall, J. N.; Bergeron,
J.; Boksenberg, A.; Savage, B. D.; Schneider, D. P.; Wolfe, A. M.
Bibcode: 1996ApJ...470L..11J
Altcode: 1996astro.ph..8080J
We report the discovery of a high-ionization broad absorption line
system at a redshift of zabs = 0.695 in the spectrum of the zem = 1.052
radio-quiet quasar PG 2302+029. Broad absorption with FWHM from 3000
to 5000 km s-1 is detected from C IV, N V, and O VI in Hubble Space
Telescope (HST) Faint Object Spectrograph spectra of the quasar. A
narrow-line system (FWHM ~ 250 km s-1) at zabs = 0.7016 is resolved
from the broad blend and includes absorption by Ly alpha and the C IV,
N V, and O VI doublets. No absorption by low-ionization metal species
(e.g., Si II and Mg II) is detected in the HST or ground-based spectra
for either the broad or the narrow system. The centroids of the broad
system lines are displaced by ~56,000 km s-1 to the blue of the quasar's
broad emission lines. The reddest extent of the broad-line absorption is
more than 50,000 km s-1 from the quasar. The properties of this system
are unprecedented, whether it is an intervening or an ejected system.
Title: Neutrino astronomy: the Sun and beyond.
Authors: Bahcall, J.; Halzen, F.
Bibcode: 1996PhyW....9...41B
Altcode:
Neutrinos might be difficult to detect, but a new generation of
experiments and telescopes could open new areas of particle physics
and regions of the universe that cannot be seen with photons.
Title: Galaxy Clustering around Nearby Luminous Quasars
Authors: Fisher, Karl B.; Bahcall, John N.; Kirhakos, Sofia; Schneider,
Donald P.
Bibcode: 1996ApJ...468..469F
Altcode: 1996astro.ph..2078F
We examine the clustering of galaxies around a sample of 20 luminous low
redshift ( z <~ 0.30) quasars observed with the Wide Field Camera-2
on the Hubble Space Telescope (HST). The HST resolution makes possible
galaxy identification brighter than V = 24.5 and as close as 1" or 2"
to the quasar. We find a significant enhancement of galaxies within a
projected separation of <~ 100 h^-1^ kpc of the quasars. If we model
the QSO/galaxy correlation function as a power law with a slope given by
the galaxy/galaxy correlation function, we find that the ratio of the
QSO/galaxy to galaxy/galaxy correlation functions is 3.8 +/- 0.8. The
galaxy counts within r < 15 h^-1^ kpc of the quasars are too high
for the density profile to have an appreciable core radius (~>100
h^-1^ kpc). Our results reinforce the idea that low redshift quasars
are located preferentially in groups of 10-20 galaxies rather than
in rich clusters. We see no significant difference in the clustering
amplitudes derived from radio-loud and radio-quiet subsamples.
Title: Hubble Deep Field Constraint on Baryonic Dark Matter
Authors: Flynn, Chris; Gould, Andrew; Bahcall, John N.
Bibcode: 1996ApJ...466L..55F
Altcode: 1996astro.ph..3035F
We use a new technique to search for faint red stars in the Hubble deep
field. We distinguish unambiguously between stars and galaxies to I =
26.3. Our results place strong and general constraints on the I-band
luminosity of the constituents of the Galactic dark halo.
Title: Solar Neutrinos: Where We Are, Where We Are Going
Authors: Bahcall, John N.
Bibcode: 1996ApJ...467..475B
Altcode: 1995hep.ph...12285B
This paper answers a series of questions: Why study solar
neutrinos? What does the combined standard model (solar plus
electroweak) predict for solar neutrinos? Why are the calculations of
neutrino fluxes robust? What are the three solar neutrino problems? What
have we learned in the first 30 years of solar neutrino research? For
the next decade, what are the most important solvable problems in
the physics of solar neutrinos? What are the most important solvable
problems in the astrophysics of solar neutrinos?
Title: Disk M Dwarf Luminosity Function from Hubble Space Telescope
Star Counts
Authors: Gould, Andrew; Bahcall, John N.; Flynn, Chris
Bibcode: 1996ApJ...465..759G
Altcode: 1995astro.ph..5087G
We study a sample of 257 Galactic disk M dwarfs (8 ≤ Mv
≤ 18.5) found in images obtained using the Hubble Space Telescope
(HST). These include 192 stars in 22 fields imaged with the repaired
Wide Field Camera (WFC2) with mean limiting mag I = 23.7 and 65 stars
in 162 fields imaged with the prerepair Planetary Camera (PC 1)
with mean limiting mag V = 21.3. We find that the disk luminosity
function (LF) drops sharply for Mv > 12 (M < 0.25
Msun), decreasing by a factor ≥ 3 by Mv ∼
14 (M ∼ 0.14 Msun). This decrease in the LF is in good
agreement with the ground-based photometric study of nearby stars by
Stobie, Ishida, & Peacock, and in mild conflict with the most recent
LF measurements based on local parallax stars by Reid, Hawley, &
Gizis. The local LF of the faint Galactic disk stars can be transformed
into a local mass function using an empirical mass-Mv
relation. The mass function can be represented analytically over
the mass range 0.1 Msun < M < 1.6 Msun
by log (φ) = -1.35 - 1.33 log (M/Msun) - 1.82[log
(M/Msun)]2, where φ is the number density
per logarithmic unit of mass. The total column density of M stars
is only ΣM = 12.4±1.9 Msun pc-2,
implying a total "observed" disk column density of Σobs
≃ 40 Msun pc-2, lower than previously believed,
and also lower than all estimates with which we are familiar of the
dynamically inferred mass of the disk. The measured scale length for
the M-star disk is 3.0±0.4 kpc. The optical depth to microlensing
toward the Large Magellanic Cloud (LMC) by the observed stars in
the Milky Way disk is τ ≤ 1 x 10-8, compared to the
observed optical depth found in ongoing experiments τobs
∼ 10-7. The M-stars show evidence for a population
with characteristics intermediate between thin disk and spheroid
populations. Approximating what may be a continuum of populations
by two separate components, we find a vertical density profile v(z)
∝ 0.80 sech2 (z/323 pc) + 0.20 exp (- |z|/656 pc). If
we combine the HST data with ground-based measurements of the local
density of M dwarfs, then a traditional double-exponential vertical
density profile is strongly excluded.
Title: Solar neutrino experiments: The next generation
Authors: Bahcall, John N.; Calaprice, Frank; McDonald, Arthur B.;
Totsuka, Yoji
Bibcode: 1996PhT....49g..30B
Altcode:
No abstract at ADS
Title: Standard neutrino spectrum from 8B decay
Authors: Bahcall, John N.; Lisi, E.; Alburger, D. E.; de Braeckeleer,
L.; Freedman, S. J.; Napolitano, J.
Bibcode: 1996PhRvC..54..411B
Altcode: 1996nucl.th...1044B
We present a systematic evaluation of the shape of the neutrino energy
spectrum produced by beta decay of 8B. We place special
emphasis on determining the range of uncertainties permitted by existing
laboratory data and theoretical ingredients (such as forbidden and
radiative corrections). We review and compare the available experimental
data on the 8B(β+)8Be(2α) decay
chain. We analyze the theoretical and experimental uncertainties
quantitatively. We give a numerical representation of the best-fit
(standard-model) neutrino spectrum, as well as two extreme deviations
from the standard spectrum that represent the total (experimental and
theoretical) effective +/-3σ deviations. Solar neutrino experiments
that are currently being developed will be able to measure the shape
of the 8B neutrino spectrum above about 5 MeV. An observed
distortion of the 8B solar neutrino spectrum outside the
range given in the present work could be considered as evidence, at an
effective significance level greater than three standard deviations,
for physics beyond the standard electroweak model. We use the most
recent available experimental data on the Gamow-Teller strengths in the
A=37 system to calculate the 8B neutrino absorption cross
section on chlorine: σCl=(1.14+/-0.11)×10-42
cm2 (+/-3σ errors). The chlorine cross section
is also given as a function of the neutrino energy. The
8B neutrino absorption cross section in gallium is
σGa=(2.46+2.1-1.1)×10-42
cm2 (+/-3σ errors).
Title: Solar Neutrinos: Where We Are, Where We Are Going
Authors: Bahcall, John N.
Bibcode: 1996NuPhS..48..309B
Altcode:
This talk answers the following questions. Why study solar
neutrinos? What does the combined standard model (solar plus
electroweak) predict for solar neutrinos? Why are the calculations of
neutrino fluxes robust? What are the three solar neutrino problems? What
have we learned in the first thirty years of solar neutrino research?
Title: How well do we (and will we) know solar neutrino fluxes and
oscillation parameters\?
Authors: Bahcall, J. N.; Krastev, P. I.
Bibcode: 1996PhRvD..53.4211B
Altcode: 1995hep.ph...12378B
Individual neutrino fluxes are not well determined by the four
operating solar neutrino experiments. Assuming neutrino oscillations
occur, the pp electron neutrino flux is uncertain by a factor of 2,
the 8B flux by a factor of 5, and the 7Be
flux by a factor of 45. For matter-enhanced oscillation (MSW)
solutions, the range of allowed differences of squared neutrino
masses, Δm2, varies between 4×10-6
eV2 and 1×10-4 eV2, while
4×10-3<=sin22θ<=1.5×10-2
or 0.5<=sin22θ<=0.9. For vacuum oscillations,
Δm2 varies between 5×10-11
eV2 and 1×10-10 eV2, while
0.7<=sin22θ<=1.0. The inferred ranges of
neutrino parameters depend only weakly on which standard solar
model is used. Calculations of the expected results of future
solar neutrino experiments (SuperKamiokande, SNO, BOREXINO, ICARUS,
HELLAZ, and HERON) are used to illustrate the extent to which these
experiments will restrict the range of the allowed neutrino mixing
parameters. For example, the double ratio (observed ratio divided
by standard model ratio) of neutral current to charged current
event rates to be measured in the SNO experiment varies, at 95%
confidence limit, over the range 1.0 (no oscillations into active
neutrinos), 3.1+1.8-1.3 (small mixing angle
MSW), 4.4+2.0-1.4 (large mixing angle MSW), and
5.2+5.6-2.9 (vacuum oscillations). We present an
improved formulation of the ``luminosity constraint'' and show that at
95% confidence limit, this constraint establishes the best available
limits on the rate of creation of pp neutrinos in the solar interior
and provides the best upper limit to the 7Be neutrino
flux. The actual rate of creation of solar neutrinos in the solar
interior to the rate predicted by the standard solar model can vary
(while holding the CNO neutrino flux constant) between 0.55 and 1.08
for pp neutrinos and between 0.0 and 6.35 for 7Be neutrinos.
Title: Temperature dependence of solar neutrino fluxes
Authors: Bahcall, John N.; Ulmer, Andrew
Bibcode: 1996PhRvD..53.4202B
Altcode: 1996astro.ph..2012B
By comparing neutrino fluxes and central temperatures calculated from
1000 detailed numerical solar models, we derive improved scaling laws
which show how each of the neutrino fluxes depends upon the central
temperature (flux ~Tm) we also estimate uncertainties
for the temperature exponents. With the aid of a one-zone model of
the Sun, we derive expressions for the temperature exponents of
the neutrino fluxes. For the most important neutrino fluxes, the
exponents calculated with the one-zone model agree to within 20%
or better with the exponents extracted from the detailed numerical
models. The one-zone model provides a physical understanding of the
temperature dependence of the neutrino fluxes. For the pp neutrino flux,
the one-zone model explains the (initially surprising) dependence of
the flux upon a negative power of the temperature and suggests a new
functional dependence. This new function makes explicit the strong
anticorrelation between the 7Be and pp neutrino fluxes. The
one-zone model also predicts successfully the average linear relations
between neutrino fluxes, but cannot predict the appreciable scatter in
a Δφi/φi versus Δφj/φj
diagram.
Title: Improved limit on charge conservation derived from
71Ga solar neutrino experiments
Authors: Norman, Eric B.; Bahcall, John N.; Goldhaber, Maurice
Bibcode: 1996PhRvD..53.4086N
Altcode:
The reported counting rates of the SAGE and GALLEX
solar neutrino detectors have been used to establish
an improved limit on the charge-nonconserving decay
71-->71Ge+neutrals. The 1σ lower limit on
the lifetime against such decays is 3.5×1026 yr. This
result can be used to establish a 1σ upper limit on the ratio
of the charge-nonconserving to the normal weak interaction decay
width of the neutron, Γ(n-->p+νe+ν¯e)/Γ
(n-->p+e-+ν¯e)<=8×10-27. This
result represents by far the most stringent limit yet derived for
charge-nonconserving decays involving baryons.
Title: The Apparently Normal Galaxy Hosts for Two Luminous Quasars
Authors: Bahcall, John N.; Kirhakos, Sofia; Schneider, Donald P.
Bibcode: 1996ApJ...457..557B
Altcode: 1995astro.ph..9031B
HST images (with WFPC2) of PHL 909 (z = 0.171) and PG 0052+251 (z =
0.155) show that these luminous radio-quiet quasars each occur in
an apparently normal host galaxy. The host galaxy of PHL 909 is an
elliptical galaxy (∼E4), and the host of PG 0052+251 is a spiral
(∼Sb). Both host galaxies are several tenths of a magnitude brighter
than L*, the characteristic Schechter luminosity of field
galaxies. The images of PHL 909 and PG 0052+251, when compared with
HST images of other objects in our sample of 20 luminous, small-redshift
(z ≤ 0.30) quasars, show that luminous quasars occur in a variety of
environments. The local environments of the luminous quasars range from
luminous ellipticals to apparently normal host galaxies, to complex
systems of interacting components, to faint (and as yet undetected)
hosts. The bright H II regions of the host galaxy of PG 0052+251
provide an opportunity to measure directly the metallicity of the
host of a luminous quasar, to establish an upper limit to the mass
of the nuclear AGN (i.e., the putative black hole source), and to
test stringently the cosmological hypothesis that the galaxy and the
quasar are both at the distance indicated by the quasar redshift. The moderately luminous host galaxies of PHL 909 and PG 0052+251 are
obvious on the HST images. Normalizing the limits of detectability using
short exposures in which the host galaxies of PHL 909 and PG 0052+251
are easily observed, we estimate that we could have detected similar
host galaxies as faint as 0.5 magnitudes less than L* in the
longer exposure HST images that have not yet shown host galaxies. The
details of the PSF subtraction are unimportant for the determination
of the host galaxy morphologies and luminosities; the major and minor
axes measured by subtracting very different stellar PSFs are the same
to ±5% and the host galaxy magnitudes are the same to ±0.1 mag.
Title: How does the sun shine?
Authors: Bahcall, J. N.; Fukugita, M.; Krastev, P. I.
Bibcode: 1996PhLB..374....1B
Altcode: 1996astro.ph..2065B
Assuming that MSW neutrino oscillations occur and ignoring all solar
physics except for the constraint that nuclear fusion produces the
solar luminosity, we show that new solar neutrino experiments are
required to rule out empirically the hypothesis that the sun shines
via the CNO cycle.
Title: Observational Searches for Solar g-Modes: Some Theoretical
Considerations
Authors: Kumar, Pawan; Quataert, Eliot J.; Bahcall, John N.
Bibcode: 1996ApJ...458L..83K
Altcode: 1995astro.ph.12091K
We argue that the solar g-modes are unlikely to have caused the discrete
peaks in the power spectrum of the solar wind flux observed by Thomson
et al (1995). The lower limit to the energy of individual g-modes,
using the amplitudes given by Thomson et al., is estimated to be at
least 1036 ergs for low-order g-modes; the resulting surface velocity
amplitude is at least 50 cm s-1, larger than the observational upper
limit (5 cm s-1). We suggest that the most likely source for the
excitation of solar g-modes is turbulent stresses in the convection
zone. The surface velocity amplitude of low-degree and low-order
g-modes resulting from this process is estimated to be of order 10-2 cm
s-1. This amplitude is interestingly close to the detection threshold of
the SOHO satellite. The long lifetime of g-modes (~106 yr for low-order
modes) should be helpful in detecting these small-amplitude pulsations.
Title: Preliminary Study of the Stellar Populations and Density
Profile of NGC 6624 Using LIST
Authors: Guhathakurta, P.; Yanny, B.; Bahcall, J. N.; Schneider, D. P.
Bibcode: 1996IAUS..174..333G
Altcode:
No abstract at ADS
Title: Hubble Space Telescope Studies of the Dense Central Regions
of Globular Clusters
Authors: Guhathakurta, P.; Yanny, B.; Schneider, D. P.; Bahcall, J. N.
Bibcode: 1996IAUS..174...19G
Altcode:
No abstract at ADS
Title: The Hubble Space Telescope Quasar Absorption Line Key
Project. VII. Absorption Systems at Z abs <= 1.3
Authors: Bahcall, John N.; Bergeron, Jacqueline; Boksenberg, Alec;
Hartig, George F.; Jannuzi, Buell T.; Kirhakos, Sofia; Sargent,
W. L. W.; Savage, Blair D.; Schneider, Donald P.; Turnshek, David A.;
Weymann, Ray J.; Wolfe, Arthur M.
Bibcode: 1996ApJ...457...19B
Altcode: 1995astro.ph..6124B
We present evidence that clumps of Lyα lines are physically associated
with about half of the extensive metal-line systems (absorption systems
with four or more observed metal-line species) found in this paper,
demonstrate that all four Lyman-limit systems discussed here correspond
to extensive metal-line absorption systems, and present an extraordinary
pair of extensive metal-line absorption systems within 2000 km s^-1^
of each other at z = 0.95 that are probably an early manifestation of
large-scale structure. These results are obtained using ultraviolet
spectra, taken with the higher resolution gratings of the Faint Object
Spectrograph of the Hubble Space Telescope (HST) for four quasars
with emission-line redshifts between 1.0 and 1.3. We also determine
the evolution of Lyα absorption lines at redshifts less than 1.3 by
combining the results for 13 smaller redshift quasars discussed in Paper
I of this series with the results for the four moderate redshift quasars
analyzed in the present paper. Absorption lines were selected, measured,
and identified algorithmically using software tested by Monte Carlo
simulations. A total of 291 absorption lines, all with a statistical
significance above a specified high threshold level, were selected and
measured. A total of 145 lines are identified as extragalactic Lyα
absorption lines. Ten of the Lyα absorption lines are found at the same
redshifts as metal-line systems. Monte Carlo simulations with pseudo-C
IV or O VI doublets were carried out to determine the probability that
a pair of absorption lines might accidentally have the appropriate
separation to be identified as either a C IV or an O VI absorption
doublet. The average number of pseudo-C IV doublets found in the real
(observed) spectra varies from 0.05 to 2.4 per spectrum within the Lyα
forest and is negligible outside the Lyα forest. For z_abs_ <= 1.3,
the density of Lyα lines with equivalent widths greater than 0.24
A is adequately fitted by dN/dz = (dN/dz)_0_(1 + z)gamma^
with (dN/dz)_0_ = 24.3 +/- 6.6 Lyα lines per unit redshift, and γ
= 0.58 +/- 0.50 (1 σ uncertainties). This rate of evolution at low
redshifts is less than the evolutionary rate inferred from several
different ground-based data samples that pertain to high redshifts,
although neither the available HST data nor the ground-based data
are sufficiently extensive to establish whether this change occurs
abruptly or gradually. The four Lyman-limit systems that are present
in the spectra analyzed here all correspond to extensive metal-line
systems. This result provides further circumstantial evidence that
many Lyman-limit systems (like many metal-line absorption systems)
are associated with galaxies. Eight extensive metal-line systems with
between five and 15 strong metal lines are identified. An approximate
estimate for the frequency of such systems is dN/dz ~ 2.5(1 + z)^0.5^
systems per unit redshift of dN/dz ~ 2.0(1 + z)^1.0^ systems per unit
redshift. About half of the extensive metal-line systems are accompanied
by clumps of neighboring (in redshift space) Lyα absorption lines,
corresponding to velocity dispersions of 600-1400 km s^-1^. In addition,
two of the extensive metal systems, found in the spectrum PKS 0122-00
at z = 0.9667 and z = 0.9531, are probably physically associated,
since they are separated by only 2000 km s^-1^. We suggest that the
metal-line systems with associated clumps of Lyα lines and the linked
pair of metal-line systems seen in the spectrum of PKS 0122-00, may
correspond to clusters, or possibly superclusters, of galaxies. The
observed gaseous structures at redshifts of 0.5-1.0 with velocity
dispersions of 6 x 102 to 1.4 x 10- km ski (or velocity spans of 1.2 x
10- to 3 x 10- km ~/1) constitute a constraint on cosmological models
of structure formation. The local mean free path (the reciprocal of
the number density times radius squared) for the clumps of Ly(alpha)
absorptions and metal-line systems is 10^-4^ Mpc^-1^. The clumps
of Lyα absorption lines clustered about metal-line systems and the
inferred rate of evolution of low and moderate redshift Lyα absorption
lines more clearly resemble the properties of galaxies and of metal
containing absorption line systems than they do the properties of
the high-redshift Lyα forest lines. These results are consistent
with two different populations of Lyα absorption lines, with type 1
being closely associated with galaxies and evolving slowly and type
2 being relative unclustered, evolving more rapidly, and dominating
the observations at large redshift.
Title: Galaxy Clustering Around Nearby Luminous Quasars
Authors: Fisher, Karl B.; Bahcall, John N.; Kirhakos, Sofia; Schneider,
Donald P.
Bibcode: 1996STIN...9621450F
Altcode:
We examine the clustering of galaxies around a sample of 20 luminous
low redshift (z approximately less than 0.30) quasars observed with the
Wide Field Camera-2 on the Hubble Space Telescope. The HST resolution
makes possible galaxy identification brighter than V = 24.5 and as
close as 2 arc-seconds to the quasar. We find a significant enhancement
of galaxies within a projected separation of approximately less than
100 (h exp -1)kpc of the quasars. The galaxy distribution around
the quasars inconsistent with the observed slope of the galaxy/galaxy
correlation function, but has an amplitude 3.8 +/- 0.8 times larger. The
galaxy counts within r less than 15 (h exp -1)kpc of the quasars are
too high for the density profile to have an appreciable core radius
(approximately greater than 100 (h exp -1)kpc). Our results reinforce
the idea that low redshift quasars are located preferentially in groups
of 10-20 galaxies rather than in rich clusters. We see no significant
difference in the clustering amplitudes derived from radio-loud and
radio-quiet subsamples.
Title: Monte Carlo Exploration of Mikheyev-Smirnov-Wolfenstein
Solutions to the Solar Neutrino Problem
Authors: Shi, X.; Schramm, D. N.; Bahcall, J. N.
Bibcode: 1996bboe.book..701S
Altcode:
We explore the impact of astrophysical uncertainties on the
Mikheyev-Smirnov-Wolfenstein (MSW) solution by calculating the allowed
MSW solutions for 1000 different solar models with a Monte Carlo
selection of solar model input parameters, assuming a full three-family
MSW mixing. Applications are made to the chlorine, gallium, Kamiokande,
and Borexino experiments. The initial GALLEX result limits the mixing
parameters to the upper diagonal and the vertical regions of the MSW
triangle. We also calculate the expected event rates in the Borexino
experiment assuming the MSW solutions implied by GALLEX.
Title: Solar interior and solar neutrinos.
Authors: Bahcall, J. N.
Bibcode: 1996stsu.conf..279B
Altcode:
The following topics were dealt with: nuclear fusion reactions in the
Sun; the chlorine solar neutrino experiment; chlorine versus Kamiokande;
GALLEX and SAGE.
Title: Globular Cluster Photometry With the Hubble Space
Telescope. V. WFPC Study of M15's Central density Cusp
Authors: Guhathakurta, Puragra; Yanny, Brian; Schneider, Donald P.;
Bahcall, John N.
Bibcode: 1996AJ....111..267G
Altcode: 1995astro.ph.12015G
We describe images of the center of the dense globular cluster M15
(NGC 7078) obtained with the Hubble Space Telescope Wide Field
and Planetary Camera 2 (WFPC2). Data taken in the F336W, F439W,
and F555W filters (approximately U, B, and V) are used to study
the surface density distribution of the ∼3×104 stars
detected in a 5 arcmin2 region within r<2' (6.7 pc)
of the cluster center. Realistic simulated images have been used to
estimate photometric errors and incompleteness in the star counts,
which are strong functions of stellar brightness and radius. We have
used a combination of point-spread-function fitting and aperture
photometry, a technique that yields more accurate photometry than
either method alone on the undersampled WFPC2 images of crowded
star fields. The error in photometry is 1σ∼0.05 mag for stars
with V<18; this increases to 1σ∼0.2 mag at V=20.5, which is
1.5 mag fainter than the main-sequence turnoff. The surface density
of stars in M15 (after correction for the effects of incompleteness
and photometric bias/scatter) is well represented by a power law in
radius: N(r)∼r-0.82±0.12,, over the radial range 0:3
(0.017 pc) to 6". The observed power law is remarkably similar to
what is expected if the center of the cluster harbors a massive black
hole. Nonparametric estimates of the density profile show a monotonic
rise with decreasing radius all the way in to r=0".3, the smallest
radius at which the density can be reliably measured; there is no
indication that the profile flattens at smaller radii. Any flat core
of radius larger than 2" (0.11 pc) in the stellar distribution is
ruled out at the ≳9S% significance level. The star count profile
is consistent with that expected from core-collapse models or with
the predicted distribution around a massive (few times 103
Msun) black hole. The close triplet of bright stars, AC 214,
is within 0".5 (1.5σ) of the cluster centroid position. The projected
density distribution of stars within the central 15" of M15 departs from
circular symmetry at the 95% level, with an ellipticity e=0.05±0.04
(90% confidence limits) at a position angle of +60°±25°, consistent
with the rotation measured by Gebhardt et al. (1995) in this region
of the cluster.
Title: PKS 2349-014: A Luminous Quasar with Thin Wisps, a Large
Off-Center Nebulosity, and a Close Companion Galaxy: Erratum
Authors: Bahcall, John N.; Kirhakos, Sofia; Schneider, Donald P.
Bibcode: 1995ApJ...454L.175B
Altcode:
In the Letter "PKS 2349-014: A Luminous Quasar with Thin Wisps,
a Large Off-Center Nebulosity, and a Close Companion Galaxy,"
by John N. Bahcall, Sofia Kirhakos, and Donald P. Schneider (ApJ,
447, L1 [1995]), there is an error in the next to last paragraph
(before the acknowledgments), second sentence. An exponent is given
incorrectly. The sentence should read: "If we suppose that we have
observed ... the required number density of black holes to be ~10-4
Mpc-3 R^{-2}20 ...." (The superscript -1 has been changed
to a -4.)
Title: Hubble Space Telescope and MERLIN Observations of the Jet in
3C 273
Authors: Bahcall, J. N.; Kirhakos, S.; Schneider, D. P.; Davis, R. J.;
Muxlow, T. W. B.; Garrington, S. T.; Conway, R. G.; Unwin, S. C.
Bibcode: 1995ApJ...452L..91B
Altcode: 1995astro.ph..9028B
We present red and blue images of the jet of the quasar 3C 273 obtained
with the WFPC2 on the Hubble Space Telescope as well as a new radio
map made with the MERLIN array. The images are of significantly better
quality than those of previous data. The two maps are aligned to an
accuracy of 0."020; this accuracy is achieved because both the quasar
and the jet are contained in both the radio and optical images. The
start of the optical jet is marked by an elongated knot which appears
identical at radio and optical wavelengths. Other knots in the optical
jet correspond to narrow oblique features within the radio outline. The
total width of the smooth emission in the optical jet is 0."7; the
FWHM of the optical knots is 0."3. The knots may trace the current
location of a narrow, perhaps helical jet lying within the outlines
of the older radio cocoon.
Title: Solar models with helium and heavy-element diffusion
Authors: Bahcall, John N.; Pinsonneault, M. H.; Wasserburg, G. J.
Bibcode: 1995RvMP...67..781B
Altcode: 1995hep.ph....5425B
Helium and heavy-element diffusion are both included in precise
calculations of solar models. In addition, improvements in the input
data for solar interior models are described for nuclear reaction rates,
the solar luminosity, the solar age, heavy-element abundances, radiative
opacities, helium and metal diffusion rates, and neutrino interaction
cross sections. The effects on the neutrino fluxes of each change in
the input physics are evaluated separately by constructing a series of
solar models with one additional improvement added at each stage. The
effective 1 σ uncertainties in the individual input quantities are
estimated and used to evaluate the uncertainties in the calculated
neutrino fluxes and the calculated event rates for solar neutrino
experiments. The calculated neutrino event rates, including all of
the improvements, are 9.3+1.2-1.4 SNU for the
37Cl experiment and 137+8-7 SNU for
the 71Ga experiments. The calculated flux of 7Be
neutrinos is 5.1 (1.00+0.06-0.07)×109
cm-2 s-1 and the flux of 8B
neutrinos is 6.6(1.00+0.14-0.17)×106
cm-2 s-1. The primordial helium abundance found
for this model is Y=0.278. The present-day surface abundance of the
model is Ys=0.247, in agreement with the helioseismological
measurement of Ys=0.242+/-0.003 determined by Hernandez
and Christensen-Dalsgaard (1994). The computed depth of the
convective zone is R=0.712Rsolar, in agreement with
the observed value determined from p-mode oscillation data of
R=0.713+/-0.003Rsolar found by Christensen-Dalsgaard et
al. (1991). Although the present results increase the predicted event
rate in the four operating solar neutrino experiments by almost 1 σ
(theoretical uncertainty), they only slightly increase the difficulty
of explaining the existing experiments with standard physics (i.e.,
by assuming that nothing happens to the neutrinos after they are
created in the center of the sun). For an extreme model in which
all diffusion (helium and heavy-element diffusion) is neglected,
the event rates are 7.0+0.9-1.0 SNU for the
37Cl experiment and 126+6-6 SNU
for the 71Ga experiments, while the 7Be
and 8B neutrino fluxes are, respectively,
4.5(1.00+0.06-0.07)×109
cm-2 s-1 and
4.9(1.00+0.14-0.17)×106
cm-2 s-1. For the no-diffusion model, the computed
value of the depth of the convective zone is R=0.726Rsolar,
which disagrees with the observed helioseismological value. The
calculated surface abundance of helium, Ys=0.268, is also
in disagreement with the p-mode measurement. The authors conclude that
helioseismology provides strong evidence for element diffusion and
therefore for the somewhat larger solar neutrino event rates calculated
in this paper.
Title: Hubble Space Telescope Images of Nearby Luminous
Quasars. II. Results for Eight Quasars and Tests of the Detection
Sensitivity
Authors: Bahcall, John N.; Kirhakos, Sofia; Schneider, Donald P.
Bibcode: 1995ApJ...450..486B
Altcode: 1995astro.ph..1018B
Observations with the Wide-Field Camera of the Hubble Space Telescope
(HST) are presented for eight intrinsically luminous quasars with
redshifts between 0.16 and 0.29. These observations, when combined
with a similar HST study of the quasar PKS 2349-014, show that luminous
nearby quasars exist in a variety of environments. Seven companion
galaxies brighter than Mv = -16.5 (H0 = 100 km
s-1 Mpc-1, Ω0 = 1.0) lie within a
projected distance of 25 kpc of the quasars; three of the companions
are located closer than 3" (6 kpc projected distance) from the quasars,
well within the volume that would be enclosed by a typical L*
host galaxy. The observed association of quasars and companion galaxies
is statistically significant and may be an important element in the
luminous-quasar phenomenon. Apparent host galaxies are detected
for three of the quasars: PG 1116+215, 3C 273, and PG 1444+407; the
hosts have an average absolute magnitude of about 0.6 mag brighter than
L*. The agreement between the previously published major-axis
directions in ground-based images and in the present HST images of
3C 273 and PG 1444+407 constitutes important evidence supporting the
reality of these candidate host galaxies. Upper limits are placed
on the visual-band brightnesses of representative galactic hosts
for all the quasars. These limits are established by placing galaxy
images obtained with HST underneath the quasars and measuring at what
faintness level the known galaxies are detected. On average, the HST
spirals would have been detected if they were as faint as 1 mag below
L*, and the early-type galaxies could have been detected
down to a brightness level of about L*, where L*
is the Schechter characteristic luminosity of field galaxies. Smooth,
featureless galaxy models (exponential disks or de Vaucouleurs profiles)
are fitted to the residual light after a best-fitting point source is
subtracted from the quasar images. The results show that smooth spiral
galaxies brighter than, on average, about L*, would have been
detected. These upper limits, or possible detections, are consistent
with, for example, the eight luminous quasars studied in this paper,
occurring in host galaxies that have a Shechter luminosity function
with a lower cutoff of in the range 0.01-0.1L*. Tests
are performed to determine if our failure to detect, in some cases,
luminous host galaxies could be an artifact caused by our analysis
procedures. These tests include comparing the measured point-spread
function (PSF) for our HST observations with the PSFs used in previous
ground-based studies of host galaxies, measuring the fluctuations
in the sky signals that were subtracted from the quasar images,
evaluating empirically the effects of using different stellar PSFs in
the analysis, carrying out the subtraction of the stellar (nuclear)
source in different ways, creating and analyzing artificial active
galactic nuclei (AGNs) with known surface brightnesses, and fitting
the observed quasar light to an analytic model that includes a host
galaxy. Our analysis procedures successfully pass all these tests.
Title: Solar neutrinos and the principle of equivalence
Authors: Bahcall, J. N.; Krastev, P. I.; Leung, C. N.
Bibcode: 1995PhRvD..52.1770B
Altcode: 1994hep.ph...10353B
We study the proposed solution of the solar neutrino problem which
requires a flavor nondiagonal coupling of neutrinos to gravity. We
adopt a phenomenological point of view and investigate the consequences
of the hypothesis that the neutrino weak interaction eigenstates
are linear combinations of the gravitational eigenstates which
have slightly different couplings to gravity, f1G and
f2G, ||f1-f2||<<1, corresponding
to a difference in redshift between electron and muon neutrinos,
Δz/(1+z)~||f1-f2||. Our χ2
analysis of the available solar neutrino data on observed event
rates rules out most of the relevant parameter space, allowing
only ||f1-f2||~3×10-14
for small values of the mixing angle
[2×10-3<~sin2(2θG)<~10-2]
and
10-16<~||f1-f2||<~10-15
for large mixing [0.6<~sin2(2θG)<~0.9]. We
show that the recoil-electron spectrum measured by the Kamiokande
II Collaboration can be used to exclude part of the allowed regions
obtained above. We analyze the prospects of using future spectral
measurements of solar neutrinos to distinguish the oscillation
mechanism due to the violation of the equivalence principle from more
conventional mechanisms which require neutrinos to have nondegenerate
masses. We find that, for small mixing angles, the flavor nondiagonal
coupling to gravity leads to predictions regarding the shape of the
8neutrino spectrum which will be distinguishable in the
upcoming SNO and Super-Kamiokande experiments and which are independent
of solar models.
Title: PKS 2349-014: A Luminous Quasar with Thin Wisps, a Large
Off-Center Nebulosity, and a Close Companion Galaxy
Authors: Bahcall, John N.; Kirhakos, Sofia; Schneider, Donald P.
Bibcode: 1995ApJ...447L...1B
Altcode: 1995astro.ph..4076B
Hubble Space Telescope (HST) images (WFC2) of PKS 2349-014 show that
this luminous nearby quasar is interacting with diffuse (presumably
galactic) material. Two thin wisps that have a total extent of about
20 kpc (for H0 = 100 km s-1 Mpc-1 and Omega 0 = 1.0) are observed to
approximately surround the quasar. One of the wisps appears to pass
through a companion galaxy that is located at a projected distance
of 3 kpc from the center of the quasar light. The companion galaxy,
if located at the distance of PKS 2349-014, has an intrinsic size and
luminosity similar to the Large Magellanic Cloud. A faint extended
nebulosity, which is detected over a region of 35 kpc x 50 kpc and is
centered about 5 kpc from the quasar nucleus, overlaps the wisps. The
immediate environment of PKS 2349-014 is different from the environments
of the other eight luminous quasars that we have studied previously
with HST. If the multiple light components of the HST images are fit
to a single de Vaucouleurs profile, as was done in previous analyses of
ground-based data, then the result obtained for the total luminosity of
the model galaxy is in agreement with the earlier ground-based studies.
Title: Host Galaxies of Luminous Nearby Quasars
Authors: Bahcall, John
Bibcode: 1995hst..prop.5849B
Altcode: 1995hst..prop.2322B
The imaging of nearby quasars in oder to measure the characteristics
of theirpresumed bright host galaxies was one of the scientific goals
used to setperformance standards during the design and development
of the HST. Thesurprising first results from our systematic program
to determine host-galaxycharacteristics are not consistent with the
standard picture, assumed in thedesign standards, that quasars occur
in well-developed, luminous (L^* orbrighter) galaxies. No bright
host galaxies were found for any of the 8luminous quasars we have
studied. For this proposal, 4-orbit exploratoryexposures will be taken
of the "cleanest" quasar for which the only candidatenebulosity detected
in Cycle 4 was extremely faint. These observations willdetect or set
limits on host galaxies about as faint as the LMC. For 3 otherquasars,
the reality of possible faint nebulosity, including three candidatefaint
host galaxies, will be tested using single-orbit observations at
rollangles different from those used in Cycle 4; these observations
will measurethe absolute magnitudes, the sizes, and the shapes of
any host galaxy materialfound. The proposed observations will also
determine the projected spacedensity of companion galaxies near (but
physically distinct from) the quasars.
Title: The Ultraviolet Emission Properties of 13 Quasars
Authors: Laor, Ari; Bahcall, John N.; Jannuzi, Buell T.; Schneider,
Donald P.; Green, Richard F.
Bibcode: 1995ApJS...99....1L
Altcode:
We analyze the ultraviolet (UV) emission properties of a sample
of 13 quasars studied with the Hubble Space Telescope (HST). The
quasars redshifts are in the range 0.165 <= z <= 2.06, and
their absolute magnitudes are in the range -30.1 <= M_v_ <=
-24.4. The data were obtained with the Faint Object Spectrograph and
have a spectral resolution of ~1300 and a signal-to-noise ratio S/N ~
20 per resolution element. We include in the analysis optical spectra
covering Hβ and the narrow [O III] λλ4959, 5007 doublet for 7 of
the 13 quasars. We find that the profile of the O VI + Lyβ blend can
be reproduced well using a "symmetric Lyα" template. The remarkable
similarity of the Lyα and O VI profiles rules out significant line
emission from a high-velocity and high ionization level component inner
to the broad line region (the very broad line region, VBLR), suggested
in a number of earlier studies of active galactic nuclei. The Hβ line
profile is in most cases different from the Lyα and C IV profiles,
which indicates that Hβ and the bulk of the UV lines are not produced
by the same distribution of clouds in the broad line region (BLR). The
following previously unobserved emission features were found in our
spectra: (1) λ ~ 832 A, most likely OII λ 833 + O III λλ833,835
emission.(2)λ ~ 1070 A, most likely an Fe II multiplet. (3)λ ~ 1175
A, probably due to C III^*^. Possible implications of these features
are briefly mentioned. The narrow [O III]-like components in both Lyα
and C III] are generally significantly weaker than expected based on
the observed [O III] λ5007 flux. This result is consistent with the
1993 finding of Wills et al. and implies that the narrow line region
(NLR) in quasars produces weaker UV /optical emission line ratios
compared with the NLR in Seyfert 2 galaxies. A study of a combined
sample of 18 quasars observed with HST(including Paper I) suggests
that the equivalent widths of all lines, excluding N V, decreases
with increasing continuum luminosity. The slopes of the EW versus
luminosity relations for the different lines do not clearly favor
explanations which invoke either a decrease in ionization parameter,
or softening of the ionizing continuum, with increasing luminosity,
as the single physical mechanism producing this effect. We verify with
our larger sample the conclusions of Paper 1 concerning the presence
of N III λ991, C III λ977, and Lyβ, the similarity of the C IV
λ1549 and Lyα profiles, and the generally small velocity shifts
of the broad line peaks relative to the peak of [O III] λ5007. In
particular, we find a very small average shift for O VI (120 +/-
270 km s^-1^ relative to Lyα), which does not support the suggestion
made in earlier studies that the line peak velocity shift increases
systematically with ionization level. The software developed for the
line profile fitting and template deblending is available upon request.
Title: Two solar neutrino problems
Authors: Bahcall, John N.
Bibcode: 1995NuPhS..43...41B
Altcode:
Twelve recently-published solar models give 7Be
neutrino fluxes that lie within a range of ±10% of the average
value, a convergence that is independent of uncertainties in the
measured laboratory rate of the 7Be( p, γ) 8B
reaction. If nothing happens to solar neutrinos after they are created
( a la standard electroweak theory) and the operating solar neutrino
experiments are correct, then the 7Be solar neutrino flux
must be less than 50% of the solar model value. At least three of
the four existing solar neutrino experiments must be wrong if: (1)
standard electroweak theory is correct, and (2) the true 7Be
neutrino flux lies within the range predicted by standard solar models.
Title: Solar neutrinos: Radiative corrections in neutrino-electron
scattering experiments
Authors: Bahcall, John N.; Kamionkowski, Marc; Sirlin, Alberto
Bibcode: 1995PhRvD..51.6146B
Altcode: 1995astro.ph..2003B
Radiative corrections to the electron recoil-energy spectra and to
total cross sections are computed for neutrino-electron scattering
by solid neutrinos. Radiative corrections change monotonically the
electron recoil spectrum for incident 8B neutrinos, with
the relative probability of observing recoil electrons being reduced by
about 4% at the highest electron energies. For p-p and 7Be
neutrinos, the recoil spectra are not affected significantly. Total
cross sections for solar neutrino-electron scattering are reduced by
about 2% compared to previously computed values. We also calculate
the recoil spectra from 13N and 15O neutrinos
including radiative corrections.
Title: Progress and prospects in neutrino astrophysics
Authors: Bahcall, John N.; Lande, K.; Lanou, R. E.; Learned, J. G.;
Robertson, R. G. H.; Wolfenstein, L.
Bibcode: 1995Natur.375...29B
Altcode: 1995astro.ph..3047B
Four separate experiments to detect neutrinos from the Sun have now
confirmed a deficit in the flux relative to the predictions of standard
theories of nuclear physics. Future experiments with new neutrino
detectors promise to reveal the explanation for this shortfall. The
planned detectors may also engender a new field of astronomy, based
on the observation of neutrino emission from distant, energetic
astrophysical sources.
Title: The Hubble Space Telescope Quasar Absorption Line Key
Project. V. Redshift Evolution of Lyman Limit Absorption in the
Spectra of a Large Sample of Quasars
Authors: Stengler-Larrea, Erik A.; Boksenberg, Alec; Steidel, Charles
C.; Sargent, W. L. W.; Bahcall, John N.; Bergeron, Jacqueline; Hartig,
George F.; Jannuzi, Buell T.; Kirhakos, Sofia; Savage, Blair D.;
Schneider, Donald P.; Turnshek, David A.; Weymann, Ray J.
Bibcode: 1995ApJ...444...64S
Altcode:
Using a sample of 119 QSOs, containing objects we have selected
having previously available high quality ground-based and IUE spectral
observations, together with Hubble Space Telescope (HST) observations
of 26 QSOs from Bahcall et al. (1993, 1995) and Impey et al. (1995) and
new optical observations of 41 objects by Steidel & Sargent (1995),
we study the redshift evolution of Lyman limit absorption systems
(LLSs; τ > 1.0) over the redshift range 0.32 <= Z_LLS_ <=
4.11. The HST observations significantly improve the determination of
the low redshift (0.4 <= Z_LLS_ <= 1.4) distribution. We find
the effect which may have been responsible for the apparent strong
evolution at Z_LLS_ => 2.5 found by Lanzetta (1991), which led him to
consider a broken, not single, power law as a better description of the
redshift distribution of LLSs. After removing objects which may bias
our sample, leaving a total of 169 QSOs, we find the distribution is
well described by a single power law, and obtain for the number density
as a function of redshift the form N(z) = N_0_(1 + z)gamma^
with γ = 1.50 +/- 0.39 and N_0_ = 0.25_+0.17_^-0.10^, consistent with
a constant comoving density of absorbers in a Friedmann universe with
q_0_ = 0 but indicating evolution if q_0_ = 1/2.
Title: What causes a quasar?
Authors: Bahcall, J. N.
Bibcode: 1995STSIN..12....1B
Altcode:
Most of the pre-launch expectations that we had of what HST would reveal
around luminous, nearby quasars have not been confirmed. Instead, the
HST pictures show a richer variety of apparently normal galaxies, of
complex systems of interacting material, and of undetected (presumably)
faint host galaxies.
Title: Star Counts from the HST Snapshot Survey. II. Wide Binaries
Authors: Gould, Andrew; Bahcall, John N.; Maoz, Dan; Yanny, Brian
Bibcode: 1995ApJ...441..200G
Altcode:
We report on a study of the first sample of wide binaries whose members
are primarily in the old component of the Galactic disk. The binaries
were discovered in 446 fields imaged with the Hubble Space Telescope
(HST) Planetary Camera to an average magnitude limit of V = 2.13,
as part of the Snapshot Survey for gravitational lenses. Most of the
fields are at moderate to high Galactic latitude. Their total area is
0.15 deg squared. Because of the relatively faint magnitude limit,
the observations are sensitive primarily to binaries in the old
disk with heights above the Galactic plane of 500-1500 pc, absolute
magnitudes of Mv = 6-11, and physical separations of
130-4000 AU. By contrast, most previous surveys have been sensitive
to binaries composed of earlier-type stars lying closer to the plane,
that is, to a younger population. We find that 4% of the disk stars
in the Snapshot sample have fainter companions within 1.5 mag, and
separations in the range 0.13 sec is less than theta which is less than
4.0 sec. The distribution of angular separations can be fitted to a
power law F(theta) is proportional to theta-l, where l =
1.2 +/- 0.4, in agreement with most previous studies. The binaries
in the Snapshot sample have bluer colors than would be expected for
random pairs of field stars.
Title: Detection of Compact Ultraviolet Nuclear Emission in LINER
Galaxies
Authors: Maoz, Dan; Filippenko, Alexei V.; Ho, Luis C.; Rix,
Hans-Walter; Bahcall, John N.; Schneider, Donald P.; Macchetto,
F. Duccio
Bibcode: 1995ApJ...440...91M
Altcode: 1994astro.ph..8042M
Low-ionization nuclear emission-line regions (LINERs), which exist in
a large fraction of galaxies, may be the least luminous manifestation
of quasar activity. As such, they may make possible the study of
the AGN phenomenon in the nearest galaxies. The nature of LINERs
has, however, remained controversial because an AGN-like nonstellar
continuum source has not been directly observed in them. We report
the detection of bright (~>2 x 10^-16^ ergs s^-1^ cm^-2^ A^-1^),
unresolved (FWHM <~ 0.1") point sources of UV (2300A) emission in
the nuclei of nine nearby galaxies. The galaxies were imaged using the
Faint Object Camera on the Hubble Space Telescope (HST), and seven of
them are from a complete sample of 110 nearby galaxies that was observed
with HST. Ground-based optical spectroscopy reveals that five of the
nuclei are LINERs, three are starburst nuclei, and one is a Seyfert
nucleus. The observed UV flux in each of the five LINERs implies an
ionizing flux that is sufficient to account to the observed emission
lines through photoionization. The detection of a strong UV continuum in
the LINERs argues against shock excitation as the source of the observed
emission lines, and supports the idea that photoionization excites
the lines in at least some objects of this class. We have analyzed
ground-based spectra for most of the northern- hemisphere galaxies in
the HST sample and find that 26 of them are LINERs, among which only
the above five LINERs have a detected nuclear UV source. There are
no obvious differences in the optical line intensity ratios between
the UV-bright and UV-dark LINERs. If all LINERs are photoionized,
then the continuum source is unobscured along our line of sight in
5/26 ~ 20% of LINERs. Alternatively, it can be argued that spectrally
similar LINERs are produced by various excitation mechanisms, and that
photoionization is responsible in only ~20% of the cases. The high
angular resolution allows us to set upper limits, typically several
parsecs, on the physical size of the compact star cluster or AGN-type
continuum source that is emitting the UV light in these objects.
Title: Limits on electron-neutrino oscillations from the GALLEX
51Cr source experiment
Authors: Bahcall, J. N.; Krastev, P. I.; Lisi, E.
Bibcode: 1995PhLB..348..121B
Altcode: 1994hep.ph...11414B
The recent result from the chromium source experiment carried
out by the GALLEX collaboration implies interesting limits on the
parameters Δm2 and sin22θ describing neutrino
oscillations. Values of Δm2 > 0.17 eV2 for
maximal mixing and of sin22θ > 0.38 for Δm2
> 1 eV2 are ruled out at 90% C.L. This result improves
by more than an order of magnitude previous limits on Δm2
derived from electron-neutrino oscillation experiments at accelerators.
Title: Solar neutrinos: what we have learned.
Authors: Bahcall, J. N.
Bibcode: 1995LNP...458...19B
Altcode: 1993astro.ph.12002B
Four solar neutrino experiments are currently taking data. The results
of these experiments confirm the hypothesis that the energy source for
solar luminosity is hydrogen fusion. However, the measured rate for
each of the four solar neutrino experiments differs significantly (by
factors of 2.0 to 3.5) from the corresponding theoretical prediction
that is based upon the standard solar model and the simplest version
of the standard electroweak theory (zero-neutrino masses, no flavor
mixing). If standard electroweak theory is correct, the energy spectrum
for 8B neutrinos created in the solar interior must be
the same (to one part in 105) as the known laboratory
8B neutrino energy spectrum. A direct comparison of the
chlorine and the Kamiokande experiments, both of which are sensitive
to 8B neutrinos, suggests that the discrepancy between
theory and observations depends upon neutrino energy, in conflict with
standard expectations. Monte Carlo studies with 1000 implementations of
the standard solar model indicate that the chlorine and the Kamiokande
experiments cannot be reconciled unless new weak interaction physics
changes the shape of the 8B neutrino energy spectrum. The
boundary conditions that the solar model luminosity equals the current
observed photon luminosity and that the solar model must be consistent
with helioseismological measurements are two of the strongest reasons
that the predictions of the standard solar model are robust. The
results of the two gallium solar neutrino experiments strengthen the
conclusion that new physics is required and help determine a relatively
small allowed region for the MSW neutrino parameters. New experiments
that will start in 1996 will test - independent of solar models -
the inference that physics beyond the standard electroweak model is
required to resolve the solar neutrino problem.
Title: How Many Solar Neutrino Experiments Are Wrong?
Authors: Bahcall, John N.
Bibcode: 1995NuPhS..38...98B
Altcode:
Ten recently-published solar models give 7Be neutrino fluxes
that lie within a range of ±10% of the average value, a convergence
that is independent of uncertainties in the measured laboratory rate of
the 7Be( p, γ) 8B reaction. If nothing happens
to solar neutrinos after they are created ( a la standard electroweak
theory) and the operating solar neutrino experiments are correct,
then the 7Be solar neutrino flux must be less than 50%
of the solar model value. At least three of the four existing solar
neutrino experiments must be wrong if: (1) standard electroweak theory
is correct, and (2) the true 7Be neutrino flux lies within
the range predicted by standard solar models.
Title: Solar Modeling
Authors: Balantekin, A. B.; Bahcall, John N.
Bibcode: 1995somo.conf.....B
Altcode: 1995QB539.S65S63...
No abstract at ADS
Title: Two Solar Neutrino Problems
Authors: Bahcall, J. N.
Bibcode: 1995fras.conf..151B
Altcode:
No abstract at ADS
Title: Has a Standard Model Solution to the Solar Neutrino Problem
been Found?
Authors: Bahcall, John N.; et al.
Bibcode: 1995somo.conf..121B
Altcode:
No abstract at ADS
Title: Solar Neutrinos: Where we are, where we are going
Authors: Bahcall, John N.
Bibcode: 1995somo.conf....1B
Altcode:
No abstract at ADS
Title: How Many Solar Neutrino Experiments Are Wrong?
Authors: Bahcall, J. N.
Bibcode: 1995psc..conf..271B
Altcode:
No abstract at ADS
Title: HST WFPC2 Study of the Density Profile and Stellar Populations
in M15
Authors: Guhathakurta, P.; Yanny, B.; Schneider, D. P.; Bahcall, J. N.
Bibcode: 1994AAS...18510414G
Altcode: 1994BAAS...26Q1490G
We describe images of the center of the dense globular cluster M15
(NGC 7078) obtained with HST's WFPC2 instrument. Data taken in
the F336W, F439W, and F555W filters (UBV) yield a color--magnitude
diagram of ~ 3*E(4) stars in a 5 arcmin(2) region within r<2'
(6.7pc) of the cluster center. Realistic simulated images have been
used to estimate photometric error and incompleteness in the star
counts. The measurement error in color is 1sigma la0 .05 mag for stars
with V<18, increasing to 1sigma ~ 0.2 mag at V=20.5, which is 1.5
mag fainter than the main sequence turnoff. The larger number of stars
detected with WFPC2 (compared to WF/PC-1) result in smaller Poisson
errors in the determination of the star count profile. The projected
radial distribution of stars (after correction for incompleteness
and photometric bias/error) is well represented by a power law: N(r)
~ {r}(alpha ) , with slope alpha =-0.7+/-0.15, into radii less than
0\farcs3 (0.015pc). Any flat core of radius larger than 1'' (0.05pc)
in the stellar distribution is ruled out at the 99% level. Only 30
blue straggler candidates are identified from the UBV data within
rla30 '', and we use the simulations to correct for contamination by
subgiant and turnoff stars. The specific frequency of blue straggler
stars (relative to red giant branch [RGB] and subgiant stars) in the
central region of M15 is f_BSS=0.05+/-0.02 which is significantly
lower than in other dense clusters. The incompleteness-corrected
radial distribution of 19<V<21 main sequence stars is consistent
with that of faint RGB/subgiant stars; there is no evidence for mass
segregation among stars in the mass interval 0.6--0.8M_sun over the
radial range 5''--2'. As noted previously, the ratio of bright RGB
stars (V<16) to to fainter RGB and subgiant stars is lower in the
inner 5'' of the cluster compared to further out (99% significance
level). Stars in the blue extension of the horizontal branch are
marginally centrally depleted relative to redder horizontal branch,
faint RGB, and subgiant stars.
Title: What Have We Learned About Solar Neutrinos?
Authors: Bahcall, John
Bibcode: 1994AAS...18510001B
Altcode: 1994BAAS...26Q1482B
The principal lessons learned from the first 30 years of solar neutrino
research will be summarized. The results from the four operating solar
neutrino experiments will be reviewed and compared with theoretical
predictions based upon standard solar models and standard electroweak
theory (zero neutrino masses, no flavor mixing). The implications of
p-mode helioseismological measurements for the neutrino problems will
be discussed. New solar neutrino experiments that are currently being
constructed will be described.
Title: Host and Companion Galaxies of Luminous, Nearby Quasars
Authors: Bahcall, John
Bibcode: 1994AAS...185.9302B
Altcode: 1994BAAS...26.1473B
The Cycle 4 HST results for the host galaxies and companions of nearby
luminous quasars will be reviewed.
Title: Solar Neutrinos: Sensitivity to Pre--Main-Sequence Evolution
and to the Depth of the Convective Zone
Authors: Bahcall, John N.; Glasner, Ami
Bibcode: 1994ApJ...437..485B
Altcode: 1994astro.ph..6039B
Predicted rates for solar neutrino experiments that are obtained with
a modified stellar evolution code originally developed to study the
advanced stages of stellar evolution are shown to be in agreement with
other recently-calculated precise solar models to about 2% (0.2 SNU
for the chlorine experiment). Different scenarios for pre-main sequence
evolution are explored and are found to change the predicted rates for
solar neutrino experiments by less than or of order 1%. The influence of
the depth of the solar convective zone on the predicted solar neutrino
fluxes is established by direct calculation. It is shown that a change
in the calculated depth of the convective zone that is five times larger
than the quoted helioseismological measurement uncertainty determined
by Christensen-Dalsgaard, Gough, & Thompson causes a change in
the predicted $^8$B neutrino flux of less than 7% and a change in the
$^7$Be neutrino flux of less than 4%. Additionally, it is shown that the
radiative opacities near the depth of the convective zone cannot differ
from the standard OPAL values by more than about 12% without causing
the calculated and measured depths of the convective zone to differ
by more than five times the helioseismological measurement uncertainty.
Title: M Dwarfs, Microlensing, and the Mass Budget of the Galaxy
Authors: Bahcall, John N.; Flynn, Chris; Gould, Andrew; Kirhakos, Sofia
Bibcode: 1994ApJ...435L..51B
Altcode: 1994astro.ph..6019B
We show that faint red stars do not contribute significantly to the
mass budget of the Galaxy or to microlensing statistics. Our results
are obtained by analyzing two long exposures of a high-latitude
field taken with the Wide Field Camera on the newly repaired {\it
Hubble Space Telescope}. Stars are easily distinguished from galaxies
essentially to the limiting magnitudes of the images. We find five
stars with $2.0<V-I<3.0$ and $I<25.3$ and no stars with
$V-I>3.0$. Therefore, main-sequence stars with $M_I>10$ that
are above the hydrogen-burning limit in the dark halo or the spheroid
contribute $<6%$ of the unseen matter. Faint red disk stars,
M-dwarfs, contribute at most $ 15%$ to the mass of the disk. We
parameterize the faint end of the cumulative distribution of stars,
$\Phi$, as a function of luminosity $L_V$, $d\Phi/d \ln L_V \propto
L_V^{-\gamma}$. For spheroid stars, $\gamma<0.32$ over the range
$6<M_V<17$, with 98% confidence. The disk luminosity function
falls, $\gamma<0$, for $15\lsim M_V\lsim 19$. Faint red stars in
the disk or thick disk, and stars with $M_V<16$ in the spheroid
contribute $\tau< 10^{-8}$ to the optical depth to microlensing
toward the Large Magellanic Cloud.
Title: HST Images of Nearby Luminous Quasars
Authors: Bahcall, John N.; Kirhakos, Sofia; Schneider, Donald P.
Bibcode: 1994ApJ...435L..11B
Altcode: 1994astro.ph..9028B
Strong upper limits are placed on the visual-band brightnesses
of galactic hosts for four luminous, radio-quiet quasars with
redshifts between 0.16 and 0.24 that were studied with the HST's
Wide Field/Planetary Camera 2 (WFPC2). Typical upper limits on the
luminosities of galactic hosts are ~1.4 mag fainter than L^*^ for
spirals and ~0.5 mag fainter than L^*^ for ellipticals. The galactic
hosts of the quasars are more than a magnitude and a half fainter than
the median integrated absolute magnitude of Seyfert galaxies. If the
detection limits are determined using featureless simulated galaxies
instead of observed galaxy images, then the detection limits for spirals
are 0.5-1.0 mag less stringent. These results are consistent with the
hypothesis that the quasar phenomenon corresponds to the early stages
of galaxy formation, before extensive star formation occurs.
Title: WFPC2 Observations of the Globular Cluster M30
Authors: Yanny, Brian; Guhathakurta, Puragra; Schneider, Donald P.;
Bahcall, John N.
Bibcode: 1994ApJ...435L..59Y
Altcode:
We describe images of the center of the dense globular cluster M30
(NGC 7099) obtained with the Hubble Space Telescope Wide Field/Planetary
Camera 2 (HST WFPC2). Data taken in the F336W, F439W, and F555W filters
(approximately U, B, and V) yield a color-magnitude diagram with
photometric errors of 1 sigma = 0.05 mag for stars with V less than
17.5, and 1 sigma approximately 0.1 mag at V = 20, which is 1.5 mag
fainter than the main-sequence turnoff. Simulations show that the star
identifications are essentially complete for stars with V less than
19.5, even in the densest regions of the cluster. The projected radial
distribution of stars can be represented by a power law distribution:
N(r) approximately ralpha, with slope alpha = -0.4 +/- 0.15,
into radii less than 0.4 sec (0.015 pc). The radial profile is also
consistent with a flat core of any radius smaller than approximately
1.5 sec (0.05 pc), but inconsistent with any core radius larger than
2.5 sec (0.09 pc). A total of 30 blue straggler candidates within 20
sec of the cluster center have been identified from the three-color
data. Their radial distribution is strongly centrally concentrated when
compared to the horizontal branch, red giant branch, or main-sequence
stars in the cluster. The abundance of blue stragglers (relative to
red giants and subgiants) within r approximately less than 20 sec of
the center of M30 is fBS = 0.19 =/- 0.04, about twice as
high as in other dense clusters.
Title: Globular Clusters Photometry With the Hubble Space
Telescope. III. Blue Stragglers and Variable Stars in the Core of M3
Authors: Guhathakurta, P.; Yanny, B.; Bahcall, J. N.; Schneider, D. P.
Bibcode: 1994AJ....108.1786G
Altcode:
This paper describes Hubble Space Telescope (HST)/Planetary
Camera-I images of the core of the dense globular cluster M3 (NGC
5272). Stellar photometry in the F555W (V) and F785LP (I) bands,
with a 1-sigma photometric accuracy of about 0.1 mag, has been used
to construct color-magnitude diagrams of about 4700 stars above
the main-sequence turnoff within r less than or approximately equal
to 1 min of the cluster center. We have also analyzed archival HST
F336W (U) images of M3 obtained by the Wide Field/Planetary Camera-I
Instrument Definition Team. The UVI data are used to identify 28 blue
straggler (BS) stars within the central 0.29 sq. arcmin. The specific
frequency of BSs in this region of M3, NBS/NV less
than (V(HB+2)) = 0.094 +/- 0.019, is about a factor of 2 -
3 higher than that found by Bolte et al. in a recent ground-based
study of the same region, but comparable to that seen in the sparse
outer parts of the same cluster and in HST observations of the core
of the higher density cluster 47 Tuc. The BSs in M3 are slightly more
centrally concentrated than red giant branch stars while horizontal
branch stars are somewhat less concentrated red giants. The radial
distribution of V-selected subgiant and turnoff stars is well fit by
a King model with a core radius rcore = 28 arcmin +/- 2
arcmin (90% confidence limits), which corresponds to 1.4 pc. Red giant
and horizontal branch stars selected in the ultraviolet data (U less
than 18) have a somewhat more compact distribution (rcore
= 22.5 arcmin). The HST U data consist of 17 exposures acquired over
a span of three days. We have used these data to isolate 40 variable
stars for which relative astrometry, brightnesses, colors, and light
curves are presented. A Kolmogorov-Smirnov test indicates that,
typically, the variability for each star is significant at the 95%
level. We identify two variable BS candidates (probably of the SX Phe
type), out of a sample of approximately 25 BSs in which variability
could have been detected. Most of the variables are RR Lyrae stars
on the horizontal branch. All of them have periods P greater than or
approximately equal 8 h.
Title: The Hubble Space Telescope Quasar Absorption Line Key
Project. VI. Properties of the Metal-rich Systems
Authors: Bergeron, Jacqueline; Petitjean, Patrick; Sargent, W. L. W.;
Bahcall, John N.; Boksenberg, Alec; Hartig, George F.; Jannuzi,
Buell T.; Kirhakos, Sofia; Savage, Blair D.; Schneider, Donald P.;
Turnshek, David A.; Weymann, Ray J.; Wolfe, Arthur M.
Bibcode: 1994ApJ...436...33B
Altcode:
We present an analysis of the properties of a sample of 18
metal-rich, low-redshift z_abs_ < z_em_ absorbers seen in low- and
medium-resolution spectra obtained for the Quasar Absorption Line Key
Project with the Hubble Space Telescope Faint Object Spectrograph. For
most of the C IV and Lyman-limit systems, observations in the optical
wavelength range of the expected associated Mg II absorption are
available. As at high redshift (z ~ 2), there are two subclasses of
absorbers which are characterized by the presence or absence of Mg
II absorption. However, some low-redshift Mg II and Fe II absorptions
originate from regions optically thin to UV ionizing photons and thus,
at low redshift, the low- ionization systems do not always trace
high opacities, as is the case at high redshift. This implies that
the mean ionization state of metal-rich, optically thin absorbing
clouds falls with decreasing redshift, which is consistent with
the hypothesis that the gas is photoionized by the metagalactic UV
background radiation field. Two main constraints are derived from
the analysis of the Lyman-limit sample, assuming photoionization
models are valid. First, a low opacity to ionizing photons (τ_LL_
<~ 1), as observed for several Mg II-Fe II systems at z ~ 0.5,
sets limits on the ionization level of hydrogen, thus on the total
hydrogen column density and the heavy element abundances, [Z/H] ~
-0.5 to -0.3. Second, the dimensions of individual Mg II clouds are
smaller than at high redshift by a factor 3-10. At z >~ 0.6, the O
VI absorption doublet is detected in four of the five z_abs_ < z_em_
systems for which the O VI wavelength range has been observed, whereas
the associated N V doublet is detected in only two cases. This suggests
that the presence of a high-ionization O VI phase is a general property
of z ~ 0.6-1 absorption systems, as is also probably the case at high
redshift. These O VI absorbers can be ionized by the UV metagalactic
field if their density is low, n_H_ <~ 3 x 10^-4^ cm^-3^. The O VI
phase would then be a homogeneous region of large extent, r ~> 50
kpc. A detailed photoionization model of the z_abs_ = 0.791 absorber
toward PKS 2145 + 06 confirms the properties derived from the Mg II,
C IV, O VI, and Lyman-limit samples. The galaxy causing this extensive
metal-line absorption system has been identified, and its possible
contribution to the UV ionizing flux does not substantially modify
the value of the derived parameters. The heavy element abundances are
about half the solar values. The O VI region has a density about 20
times lower than the Mg II clouds and a size of ~70 kpc. Alternatively,
the high-ionization phase could be collisionally ionized and trace gas
associated with a possible group of galaxies at the absorber redshift.
Title: Two solar neutrino problems
Authors: Bahcall, John N.
Bibcode: 1994PhLB..338..276B
Altcode: 1994PhLB..338..276N; 1994astro.ph..7048B
It is shown that there are two solar neutrino problems:
(1) the incompatibility of the chlorine and Kamiokande solar
neutrino experiments; and (2) the low counting rates in the gallium
experiments. Eleven recently-published solar models give 7Be
neutrino fluxes that lie within a range of +/-10% of the average
value, a convergence that is independent of uncertainties in the
measured laboratory rate of the 7Be(p,γ)8B
reaction. If nothing happens to solar neutrinos after they are created
(à la standard electroweak theory) and the operating solar neutrino
experiments are correct, then the 7Be solar neutrino flux
must be less than 50% of the solar model value. At least three of
the four existing solar neutrino experiments must be wrong if. (1)
standard electroweak theory is correct, and (2) the true 7Be
neutrino flux lies within the range predicted by standard solar models.
Title: Has a standard model solution to the solar neutrino problem
been found?
Authors: Bahcall, J. N.; Barnes, C. A.
Bibcode: 1994STIN...9520490B
Altcode:
The claim by Dar and Shaviv that they have found a standard model
solution to the solar neutrino problem is based upon an incorrect
assumption made in extrapolating nuclear cross sections and the
selective use of a small fraction of the nuclear physics and of the
neutrino data. In addition, five different solar model codes show that
the rate obtained for the chlorine experiment using the Dar- Shaviv
stated parameters differs by a least 14(sigma) from the observed rate.
Title: The HST Quasar Absorption Line Key Project VIII. CCD Imaging
of Hubble Space Telescope Quasar Fields
Authors: Kirhakos, Sofia; Sargent, W. L. W.; Schneider, Donald P.;
Bahcall, John N.; Jannuzi, Buell T.; Maoz, Dan; Small, Todd A.
Bibcode: 1994PASP..106..646K
Altcode: 1994PASP..106..646P
We present an analysis of CCD images of more than 100 quasars; many
of the objects have been or will be observed in the HST Key Project
Quasar Absorption Line Survey. The data set consists of B, g, and i
photometry of 117 quasars and deeper g (limiting magnitude of ~22)
images of 101 quasar fields. Positions accurate to ~1", measured with
the Space Telescope Science Institute's Astrometric Support Program,
are listed for all of the quasars in this study. Positions, magnitudes,
and classifications of stars and galaxies located within ~100" of the
quasars are given for all of the dep g data. The positions of the stars
and galaxies relative to the quasar are accurate to ~0.5". The results
presented here can be used to prepare spectroscopic programs designed to
obtain redshifts of galaxies in the fields of these quasars. (SECTION:
Quasars and Active Galactic Nuclei)
Title: Globular Cluster Photometry With The Hubble Space
Telescope. II. U,V, And I Measurements of M15
Authors: Yanny, Brian; Guhathakurta, Puragra; Bahcall, John N.;
Schneider, Donald P.
Bibcode: 1994AJ....107.1745Y
Altcode:
The projected density distribution of resolved stars near the center
of M15 is shown to be consistent with either a power-law cusp N(r)
approximately ralpha, with alpha approximately -0.85 +/-
0.2, or with a King model with a core of radius approximately less than
2 sec. The inferred slope is in agreement with the theoretical value,
alpha = -0.75, calculated by Bahcall and Wolf for the distribution
of equal-mass stars surrounding a massive black hole and is also
consistent with the radial profile expected from core collapse without
a central black hole. The object AC 214 is a candidate for the central
density cusp. Analysis of Monte Carlo simulations of the diffuse light
indicates that, using current analysis techniques and available data,
the residual light is not a reliable indicator of the true density
distribution. This is contrary to earlier work. Photometric measurements
in V and I of more than 5 x 103 stars (and in U, V, and
I of approximately greater than 1500 stars) are used to construct
color-magnitude diagrams in the central 1 min of M15. Fourteen blue
straggler candidates are identified in the inner 20 sec. The central
color gradient noticed by previous researchers is caused by a central
depletion of bright red giant stars rather than an excess of blue
stragglers or blue horizontal branch stars.
Title: Solar Neutrinos: Where We Are, Where We Are Going
Authors: Bahcall, John N.
Bibcode: 1994astro.ph..4070B
Altcode:
There are four important facts about solar neutrinos. They are listed
in order of importance in this abstract and discussed more in the
text of the talk. First, solar neutrinos have been detected in four
experiments with approximately the energies and fluxes predicted by the
standard solar model, confirming the hypothesis that the energy source
for the solar luminosity is the fusion of light elements. Second,
the measured event rates are significantl less than the event rates
predicted by the combined standard solar and electroweak models in all
four experiments. Third, a comparison of the event rates measured in
the chlorine experiment (threshold 0.8 Mev) and the neutrino-electron
scattering experiment (Kamiokande II, threshold 7.5 MeV) indicates
that the deficiency of electron-type neutrinos at the earth is energy
dependent, if the rates and the uncertainties in both experiments
have been correctly understood. The inference that the deficiency
is energy-dependent conflicts with the simplest version of standard
electroweak theory. Fourth, experiments are being constructed that
have the capabilities to determine conclusively if new neutrino physics
is required.
Title: Distantly detecting deuterium
Authors: Bahcall, John N.
Bibcode: 1994Natur.368..584B
Altcode:
No abstract at ADS
Title: Has A Standard Model Solution to the Solar Neutrino Problem
Been Found?
Authors: Bahcall, John N.
Bibcode: 1994astro.ph..4002B
Altcode:
The claim by Dar and Shaviv that they have found a standard model
solution to the solar neutrino problem is based upon an incorrect
assumption made in extrapolating nuclear cross sections and the
selective use of a small fraction of the nuclear physics and of the
neutrino data. In addition, five different solar model codes show that
the rate obtained for the chlorine experiment using the Dar-Shaviv
stated parameters differs by at least $14 \sigma$ from the observed
rate.
Title: 7Be solar neutrino line: A reflection of the
central temperature distribution of the Sun
Authors: Bahcall, John N.
Bibcode: 1994PhRvD..49.3923B
Altcode: 1994astro.ph..1024B
A precise test of the theory of stellar evolution can be performed by
measuring the average difference in energy between the neutrino line
produced by 7Be electron capture in the solar interior
and the corresponding neutrino line produced in a terrestrial
laboratory. This energy shift is calculated to be 1.29 keV (to an
accuracy of a few percent) for the dominant ground-state to ground-state
transition. The energy shift is approximately equal to the average
temperature of the solar core, computed by integrating the temperature
over the solar interior with a weighting factor equal to the locally
produced 7Be neutrino emission. Therefore, a measurement
of the energy shift is a measurement of the central temperature
distribution of the Sun. The energy profile of the 7Be line
is derived analytically and is evaluated numerically. The line shape
is asymmetric: on the low-energy side, the line shape is Gaussian with
a half-width at half-maximum of 0.6 keV and, on the high-energy side,
the line shape is exponential with a half-width at half-maximum of 1.1
keV. The effective temperature of the high-energy exponential tail is
15×106 K. The energy profile of the 7Be neutrino
line should be taken into account in calculations of vacuum neutrino
oscillations and of the absorption cross section for 7Be
solar neutrinos incident on 7Li nuclei. The characteristic
modulation of the 7Be line shape that would be caused
by either vacuum neutrino oscillations or by matter-enhanced (MSW)
neutrino oscillations is shown to be small. Other frequently discussed
weak interaction solutions to the solar neutrino problem are also not
expected to change significantly the line profile.
Title: Microlensing Events: Thin Disk, Thick Disk, or Halo?
Authors: Gould, Andrew; Miralda-Escude, Jordi; Bahcall, John N.
Bibcode: 1994ApJ...423L.105G
Altcode:
The three recently announced candidate microlensing events toward the
Large Magellanic Cloud (LMC) could arise from compact objects in a thin
disk, a thick disk, or a halo. We discuss five observations that could
among these possibilities: (1) The optical depth to the LMC, which can
be measured from the rate and duration of events. The ratios of upper
limits to the optical depths are 1:2.5:15 for the thin disk, thick disk,
and halo models, so a large optical depth can rule out the thin disk
and thick disk models, (2) The ratios of the optical depths to the SMC
and LMC for the three models: 0.6, 0.6, and 1-1.5. (3) Deviations from
the normal shape of the microlensing light curve, caused by parallax
effects. The ratios of the fraction of events with detectable parallax
effects are 70:15:1. If events are identified in real time and are
observed with high-precision relative photometry (~0.02 mag), then
parallax effects can be measured for most thin-disk events and ~15%
of thick-disk events. (4) The characteristic masses inferred from
the mean duration of events. These are in the ratio of 1.2:1:1.5,
so this can be at most a marginal test of the three models. (5) The
ratios of optical depths to the bulge (in excess of that produced by
known stars) and to the LMC. These are 45, 5.5, and 1 for a thin disk,
a thick disk, and a halo. At present the observations favor a thick-disk
or halo origin of the lenses, or similar contributions from more than
one structure, but do not exclude the thin disk as the main contributor.
Title: Is large lepton mixing excluded\?
Authors: Smirnov, Alexei Yu.; Spergel, David N.; Bahcall, John N.
Bibcode: 1994PhRvD..49.1389S
Altcode: 1993hep.ph....5204S
The original ν¯μ- (or ν¯τ-) energy
spectrum from the gravitational collapse of a star has a
larger average energy than the spectrum for ν¯e
since the opacity of ν¯e exceeds that of
ν¯μ (or ντ). Flavor neutrino conversion
ν¯e⇆ν¯μ induced by lepton mixing
results in partial permutation of the original ν¯e
and ν¯μ spectra. An upper bound on the permutation
factor p<=0.35 (99% C.L.) is derived using the data from SN
1987A and a range of models of the neutrino emission. The relation
between the permutation factor and the vacuum mixing angle is
established, which leads to the upper bound on this angle. The upper
bound sin22θ>0.7-0.9 excludes the large mixing angle
solutions of the solar neutrino problem: ``just-so'' and, partly, MSW,
as well as part of the region of the νe-νμ
oscillation space which could be responsible for the atmospheric muon
neutrino deficit. These limits are sensitive to the predicted neutrino
spectrum and can be strengthened as supernova models improve.
Title: VizieR Online Data Catalog: Positions of high-redshift luminous
quasars (Schneider+ 1992)
Authors: Schneider, D. P.; Bahcall, J. N.; Saxe, D. H.; Bahcall,
N. A.; Doxsey, R.; Golombek, D.; Krist, J.; McMaster, M.; Meakes,
M.; Lahav, O.
Bibcode: 1994yCat.7149....0S
Altcode:
The non-proprietary HST Snapshot Survey produced Planetary Camera
images of high-redshift, luminous quasars. The aim of the program is to
determine the frequency of multiple imaged QSOs down to angular scales
of 0.15". Detailed descriptions of the program are given in Bachall et
al. (1992ApJ...387...56B) and Maoz et al. (1992ApJ...394...51M). The
sample was taken from the 3rd and 4th editions of the catalog of
Veron-Cetty and Veron (1987ESOSR...5....1V, 1989ESOSR...7....1V). The
target positions taken from these catalogs were fed to GASP, the
STSci Guide Star Astrometric Support Program, to generate revised
positions from regions extracted from the STSci's digitized sky
survey. The printed version of the catalog does not contain the Veron
1950 coordinates nor the difference between these and the GASP derived
1950 coordinates that are contained in this version. (1 data file).
Title: Element Diffusion in the Solar Interior
Authors: Thoul, Anne A.; Bahcall, John N.; Loeb, Abraham
Bibcode: 1994ApJ...421..828T
Altcode: 1993astro.ph..4005T
We study the diffusion of helium and other heavy elements in the solar
interior by solving exactly the set of flow equations developed by
Burgers for a multi-component fluid, including the residual heat-flow
terms. No approximation is made concerning the relative concentrations
and no restriction is placed on the number of elements considered. We
give improved diffusion velocities for hydrogen, helium, oxygen
and iron, in the analytic form derived previously by Bahcall and
Loeb. These expressions for the diffusion velocities are simple to
program in stellar evolution codes and are expected to be accurate
to $\sim 15\%$. Our complete treatment of element diffusion can be
directly incorporated in a standard stellar evolution code by means
of an exportable subroutine, but, for convenience, we also give simple
analytical fits to our numerical results.
Title: Electron Capture and Nuclear Matrix Elements of Be7
Authors: Bahcall, J. N.
Bibcode: 1994snft.book..198B
Altcode:
No abstract at ADS
Title: Termination of the Proton-Proton Chain in Stellar Interiors
Authors: Parker, P. D.; Bahcall, J. N.; Fowler, W. A.
Bibcode: 1994snft.book..212P
Altcode:
No abstract at ADS
Title: Standard Solar Models, With and Without Helium Diffusion,
and the Solar Neutrino Problem
Authors: Bahcall, J. N.; Pinsonneault, M. H.
Bibcode: 1994snft.book...60B
Altcode:
No abstract at ADS
Title: The Rate of the Proton-Proton Reaction
Authors: Kamionkowski, Marc; Bahcall, John N.
Bibcode: 1994ApJ...420..884K
Altcode: 1993astro.ph..5020K
We re-evaluate the matrix element for the proton-proton reaction
which is important for stellar-evolution calculations and for the
solar-neutrino problem. We self-consistently determine the effect
of vacuum polarization on the matrix element by first correcting the
low-energy scattering data to account for vacuum polarization. We then
calculate the proton-proton wave function by integrating the Schrodinger
equation with vacuum polarization included. We use improved data
for proton-proton scattering and for the deuteron wave function. We
evaluate the uncertainties that are due to experimental error and
estimate those that are due to theoretical inadequacies. We estimate the
theoretical uncertainty by using six different deuteron potentials and
five different proton-proton potentials. Vacuum polarization decreases
the calculated value by $0.6_{-0.4}^{+0.1}$\%. The complete result is
$\Lambda^2=6.92\times(1\pm0.002^{+0.014}_{-0.009})$ where the first
uncertainty is due to experimental errors and the second uncertainty
is due to theoretical uncertainties. Our value of $\Lambda^2$ is 2\%
smaller than the value obtained in 1969 by Bahcall and May. The improved
calculations of the rate of the $pp$ reaction described here increase
slightly the predicted event rates for the chlorine and the Kamiokande
solar-neutrino experiments.
Title: Vacuum-polarization corrections to solar-fusion rates
Authors: Kamionkowski, Marc; Bahcall, John N.
Bibcode: 1994PhRvC..49..545K
Altcode: 1993astro.ph..6024K
The vacuum-polarization (VP) corrections to rates for nuclear-fusion
reactions in the pp chain and in the CNO cycle are calculated. For
the reactions of particular importance to the solar-neutrino
problem, the 3He(3He,2p)4He,
3He(α,γ)7Be, 7Be(p,γ)8B,
and 14N(p,γ)15O reactions, we find the magnitude
of the effect to be less than 2%. The effect of VP on all the other
reaction rates is expected to be of a similar order of magnitude. We
discuss how these results affect the predicted fluxes of solar
neutrinos.
Title: The Stellar Density Distributions in the Centers of Galactic
Globular Clusters: Cycle 4 Observations
Authors: Bahcall, John
Bibcode: 1994hst..prop.5603B
Altcode: 1994hst..prop.2044B
A single exposure in the F336W filter will be made of M30 using the
PC CCD of the WFPC2.
Title: The 7Be Electron-Capture Rate
Authors: Bahcall, J. N.; Moeller, C. P.
Bibcode: 1994snft.book..222B
Altcode:
No abstract at ADS
Title: Standard Solar Models and the Uncertainties in Predicted
Capture Rates of Solar Neutrinos
Authors: Bahcall, J. N.; Huebner, W. F.; Lubow, S. H.; Parker, P. D.;
Ulrich, R. K.
Bibcode: 1994snft.book...57B
Altcode:
No abstract at ADS
Title: Are Neutrinos Stable Particles?
Authors: Bahcall, J. N.; Cabibbo, N.; Yahil, A.
Bibcode: 1994snft.book..285B
Altcode:
No abstract at ADS
Title: Solar Neutrinos. I. Theoretical
Authors: Bahcall, J. N.
Bibcode: 1994snft.book....9B
Altcode:
No abstract at ADS
Title: Solar Neutrino Flux
Authors: Bahcall, J. N.; Fowler, W. A.; Iben, I., Jr.; Sears, R. L.
Bibcode: 1994snft.book...30B
Altcode:
No abstract at ADS
Title: The Rate of the Proton-Proton Reaction
Authors: Bahcall, J. N.; May, R. M.
Bibcode: 1994snft.book..218B
Altcode:
No abstract at ADS
Title: The Stellar Density Distributions in the Centers of Galactic
Globular Clusters
Authors: Bahcall, John
Bibcode: 1994hst..prop.5687B
Altcode: 1994hst..prop.2128B
Short exposures will be made of all galactic globular clusters
with distance moduli less than 15.5 mag and galactic latitude
above or below 15 degrees. A search will be made for cusps
in the stellar density distributions and the colors will be
measured for the brightest stars in the cores of the clusters. ST
observations are required in order to reach the innermost regions
of the clusters with sufficient resolution to separate individual
stars. ********************************************************** This
program contains only the exposures that were not completed prior to
the first HST servicing mission.
Title: Do Solar-Neutrino Experiments Imply New Physics?
Authors: Bahcall, J. N.; Bethe, H. A.
Bibcode: 1994snft.book...65B
Altcode: 1993astro.ph..7013B
Physics beyond the simplest version of the standard electroweak
model is required to reconcile the results of the chlorine and the
Kamiokande solar neutrino experiments. None of the 1000 solar models
in a full Monte Carlo simulation is consistent with the results of
the chlorine or the Kamiokande experiments. Even if the solar models
are forced articficially to have a ${}^8 B$ neutrino flux in agreement
with the Kamiokande experiment, none of the fudged models agrees with
the chlorine observations. This comparison shows that consistency of
the chlorine and Kamiokande experiments requires some physical process
that changes the shape of the ${}^8 B$ neutrino energy spectrum. The
GALLEX and SAGE experiments, which currently have large statistical
uncertainties, differ from the predictions of the standard solar model
by $2 \sigma$ and $3 \sigma$, respectively. The possibility that the
neutrino experiments are incorrect is briefly discussed.
Title: Solar Neutrino Experiments
Authors: Bahcall, J. N.
Bibcode: 1994snft.book...29B
Altcode:
No abstract at ADS
Title: Neutrino-Spectroscopy of the Solar Interior
Authors: Bahcall, J. N.
Bibcode: 1994snft.book..113B
Altcode:
No abstract at ADS
Title: Present Status of the Theoretical Predictions for the
37Cl Solar-Neutrino Experiment
Authors: Bahcall, J. N.; Bahcall, N. A.; Shaviv, G.
Bibcode: 1994snft.book...45B
Altcode:
No abstract at ADS
Title: Imaging and Spectroscopy of a Complete Sample of Bright Nearby
Quasars: I. Imaging
Authors: Bahcall, John
Bibcode: 1994hst..prop.5099B
Altcode: 1994hst..prop.1611B
A sample of 7 Palomar Green quasars will be imaged with the WFC. The
morphology of the host galaxies is not discernible - in the presence of
a bright center source (quasar) - with ground based observations, but
will be determined with ST unless the galaxies are unexpectedly faint.
Title: Lepton Non-Conservation and Solar Neutrinos
Authors: Bahcall, J. N.; Frautschi, S. C.
Bibcode: 1994snft.book..277B
Altcode:
No abstract at ADS
Title: Solar Neutrinos
Authors: Bahcall, J. N.
Bibcode: 1994snft.book...23B
Altcode:
No abstract at ADS
Title: Proposed Solar-Neutrino Experiment Using 71Ga
Authors: Bahcall, J. N.; Cleveland, B. T.; Davis, R., Jr.; Dostrovsky,
I.; Evans, J. C., Jr.; Frati, W.; Friedlander, G.; Lande, K.; Rowley,
J. K.; Stoenner, R. W.; Weneser, J.
Bibcode: 1994snft.book..116B
Altcode:
No abstract at ADS
Title: Sensitivity of the Solar-Neutrino Fluxes
Authors: Bahcall, J. N.; Bahcall, N. A.; Ulrich, R. K.
Bibcode: 1994snft.book...54B
Altcode:
No abstract at ADS
Title: Predictions for a Liquid Argon Solar Neutrino Detector
Authors: Bahcall, J. N.; Baldo-Ceolin, M.; Cline, D. B.; Rubbia, C.
Bibcode: 1994snft.book..123B
Altcode:
No abstract at ADS
Title: On the Problem of Detecting Solar Neutrinos
Authors: Bahcall, J. N.; Davis, R., Jr.
Bibcode: 1994snft.book...42B
Altcode:
No abstract at ADS
Title: Solar Neutrinos: A Scientific Puzzle
Authors: Bahcall, J. N.; Davis, R., Jr.
Bibcode: 1994snft.book..141B
Altcode:
No abstract at ADS
Title: WFC Imaging of Nearby Bright Quasars
Authors: Bahcall, John
Bibcode: 1994hst..prop.5343B
Altcode: 1994hst..prop.1789B
We will obtain deep WFPC2 images of bright, nearby quasars to
investigate the optical morphology of their host galaxies. The high
angular resolution of HST will allow one to perform a number of
quantitative measurements of the morphology and luminosities of host
galaxies. The proposed HST observations will reveal the relationship
between the properties of the host galaxy and quasar luminosity (both
optical and radio), and how quasar host galaxies differ from field or
cluster galaxies. The sample consists of 13 quasars with z < 0.3,
M_V < -23 (Ho = 100), and |b| > 35. Each quasar will be imaged in
a Wide Field Camera CCD through the F606W filter. The objects in this
proposal span a range of quasar luminosities (up to M_V of -24.5; Ho =
100) and redshifts (0.09 < z < 0.265). Three of the 13 quasars
are radio-loud; the combined GTO/GO sample of 22 objects contains six
radio-loud quasars.
Title: Quasar Absorption Line Survey - Cycle 4 High
Authors: Bahcall, John
Bibcode: 1994hst..prop.5664B
Altcode: 1994hst..prop.2105B
The Absorption Line Survey of bright quasars provides a homogeneous
data base for studying fundamental questions about the origin and
evolution of gaseous systems in the universe. The initial results
determine at small redshifts the number densities of Ly-ALPHA systems,
of metal-lines and extragalactic halos, of Lyman-limit systems,
of associated absorption systems, and the shapes and intensities of
quasar emission lines and spectral energy distributions. The survey
reveals that much of the sky is covered by high or very high velocity
metal-line clouds present in the Galactic halo. A larger sample, which
includes the requested Cycle 3 observations, is required to answer many
important questions. For example, what is the correlation function
of Ly-ALPHA systems at small redshifts? What fraction of the metal,
the Ly-ALPHA, and the Ly-limit systems are associated with galaxies
and what are the characteristic sizes of the outer gaseous regions of
different types of galaxies? Do absorbing systems show evidence of the
large-scale structure seen with galaxies and clusters of galaxies? The
observations requested in Cycle 3 will extend the region of coverage
of the Key Project sample from the redshift range of z = 0.0 to 1.0
(Cycles 1& 2) to z = 0.0 to 1.6 (Cycles 1-3). THIS FILE CONTAINS
THE HIGH PRIORITY OBSERVATIONS FROM CYCLES 2 and 3 WHICH WERE NOT
COMPLETED IN THOSE CYCLES.
Title: Standard Model Expectations: Introduction
Authors: Bahcall, John N.
Bibcode: 1994snft.book....3B
Altcode:
No abstract at ADS
Title: Neutrino Opacity. I. Neutrino-Lepton Scattering
Authors: Bahcall, J. N.
Bibcode: 1994snft.book...18B
Altcode:
No abstract at ADS
Title: Solar Models, Neutrino Experiments, and Helioseismology
Authors: Bahcall, J. N.; Ulrich, R. K.
Bibcode: 1994snft.book...58B
Altcode:
No abstract at ADS
Title: Solar neutrinos. The first thirty years.
Authors: Bahcall, J. N.; Davis, R., Jr.; Parker, P.; Smirnov, A.;
Ulrich, R.
Bibcode: 1994snft.book.....B
Altcode: 1994FrPhy..92.....B; 1994QB539.S65S64...
The editors have selected a representative collection of papers that
they believe to be important in the development of solar neutrino
research. They chose to begin their selection of papers in the year
1964 when it first became apparent that a practical experiment to
detect solar neutrinos was possible.
Title: The Ultraviolet Emission Properties of Five Low-Redshift Active
Galactic Nuclei at High Signal-to-Noise Ratio and Spectral Resolution
Authors: Laor, Ari; Bahcall, John N.; Jannuzi, Buell T.; Schneider,
Donald P.; Green, Richard F.; Hartig, George F.
Bibcode: 1994ApJ...420..110L
Altcode: 1993astro.ph..5026L
We analyze the ultraviolet (UV) emission line and continuum properties
of five low-redshift active galactic nuclei (four luminous quasars:
PKS 0405 - 123, H1821 +643, PG 0953+414, and 3C 273, and one bright
Seyfert 1 galaxy: Mrk 205). The HST spectra have higher signal-to-noise
ratios (typically ~60 per resolution element) and spectral resolution
(A = 1300) than all previously published UV spectra used to study
the emission characteristics of active galactic nuclei. We include in
the analysis ground-based optical spectra covering Hβ and the narrow
[O III] λλ4959,5007 doublet. The following new results are obtained:
Lyβ/Lyα = 0.03-0.12 for the four quasars, which is the first accurate
measurement of the long-predicted Lyβ intensity in QSOs. The cores of
Lyα and C IV are symmetric to an accuracy of better than 2.5% within
about 2000 km s^-1^ of the line peak. This high degree of symmetry
of Lyα argues against models in which the broad line cloud velocity
field has a significant radial component. The observed smoothness of the
Lyα and C IV line profiles requires at least ~10^4^ individual clouds
if bulk velocity is the only line-broadening mechanism. The overall
similarity of the Lyα and C IV λ1549 profiles rules out models for the
broad-line region (BLR) with a radial distribution of virialized clouds
having an ionization parameter U is proportional to Radius^-1^. The
measured high values of O VI λ1034/Lyα and low values of C III λ977/O
VI λ1034 imply a BLR component with U ~ 1. The red-wing flux in O
VI relative to Lyα suggests the presence of an inner, high-velocity,
optically thin component with U > 1 in the BLR. The N V/Lyα ratio
is 0.135 +/- 0.01 for the four quasars, which may be an indication of
higher than solar N abundance and metallicity. The maximum contribution
of a narrow ([O III]-like) component is about 3%-6% of the total
broad-line flux; this limit is generally highest for C III]. This
result constrains the covering factor of the narrow line region or
indicates the presence of dust. An unresolved component having full
width at half-maximum less than 230 km s^-1^ typically contributes
less than 0.5% of the observed broad lines flux. The HST data permit
the first relatively accurate measurements of the Lyγ, C III λ977,
S VI λλ933, 945, and the N III λ991 emission lines, as well as the
measurement of a number of other weak or strongly blended lines at λ
> 1216 A. In agreement with observations of high-redshift quasars,
the peaks of Lyα, C IV, and C III] are blueshifted by ~200 km s^-1^
relative to [O III] λ5007, while He II λ1640 is shifted by about
500 km s^-1^. The low ionization lines, Mg II, Hβ, and O I λ1304,
are in most cases only marginally shifted to the red.
Title: The centers of two very dense Globular Clusters
Authors: Yanny, Brian; Guhathakurta, Puragra; Schneider, Donald P.;
Bahcall, John
Bibcode: 1993AAS...183.2402Y
Altcode: 1993BAAS...25.1329Y
We present Hubble Space Telescope Planetary Camera imaging observations
of the centers of very dense globular clusters. We discuss the radial
profile of stars in the central 2 arcsec of these clusters and compare
with predictions of theories of post core collapse cluster profiles. We
discuss the appearance of various negative power law stellar density
slopes in the center of a cluster under typical observing conditions
and compare with the HST observations. We find we cannot rule out
a cusp of slope -0.8 in projected stellar density as a function of
radius in the center of the cluster M15 (NGC 7078).
Title: A Very Large Array Search for Emission From HI Associated
With Nearby Lyman alpha Absorption
Authors: van Gorkom, J. H.; Bahcall, J. N.; Jannuzi, B. T.; Schneider,
D. P.
Bibcode: 1993AJ....106.2213V
Altcode: 1993ApJS...89.2213V
We present a sensitive VLA search for H I emission from the vicinity of
the Lyman α clouds in the Virgo Cluster, which were recently discovered
with HST in absorption toward the nearest quasar 3C 273. We searched
an area of 40 by 40 arcmin centered on 3C 273, covering a velocity
range from 840 to 1840 km s^-1^. The bandpass was self- calibrated
on 3C 273 leading to a spectral dynamic range of better than 10^5^ to
1. No H I was detected. The rms noise in the final images corresponds
to a 3σ column density sensitivity of 2.8 x 10^19^ cm^- 2^ on scales
of a few kpc. Small H I clouds could have been detected down to a
few times 10^6^ M_sun_. Our failure to detect H I in emission at the
higher column densities sets a lower limit to the radius of the Lyman
α clouds of 3.9 kpc, assuming a spherical geometry.
Title: The Effects of Helium Diffusion on Solar p-Mode Frequencies
Authors: Guenther, D. B.; Pinsonneault, M. H.; Bahcall, J. N.
Bibcode: 1993ApJ...418..469G
Altcode:
Precise solar models are computed with and without including helium
diffusion. We show that the inclusion of helium diffusion according
to the Bahcall-Loeb prescription causes systematic shifts of order
1-5 μHz in the predicted p-mode oscillation frequencies. Calculations
with the diffusion coefficients multiplied and divided by two show that
the inferred effects are linearly proportional to the magnitude of the
diffusion. Relative to a model that does not include helium diffusion,
the models with diffusion increase the frequencies of low-l modes and
decrease the frequencies of high-l modes. The effect on the frequencies
of intermediate-l modes depends on whether or not the modes penetrate
significantly below the convection zone. Future observations may reveal
this characteristic signature of diffusion. Unfortunately, systematic
discrepancies of order 10 μHz out of 3000 μHz prevent, at present,
a direct test of the signature of helium diffusion. Improvements in
the treatment of nonadiabatic effects and in the opacity and equation
of state may remove the largest discrepancies and permit measurements
that are specifically sensitive to helium diffusion.
Title: Central temperature of the Sun can be measured via the
7Be solar neutrino line
Authors: Bahcall, John N.
Bibcode: 1993PhRvL..71.2369B
Altcode: 1993hep.ph....9292B
A precise test of the theory of stellar evolution can be performed
by measuring the difference in average energy between the neutrino
line produced by 7Be electron capture in the solar
interior and the corresponding neutron line produced in a terrestrial
laboratory. The high temperatures in the center of the Sun broaden the
line asymmetrically, FWHM =1.6 keV, and cause an average energy shift
of 1.3 keV. The width of the 7Be neutrino line should be
taken into account in calculations of vacuum neutrino oscillations.
Title: Star Counts from the Hubble Space Telescope Snapshot
Survey. I. Galactic Models
Authors: Gould, A.; Bahcall, J. N.; Maoz, D.
Bibcode: 1993ApJS...88...53G
Altcode:
We report on a photometric study of stars from 450 fields at high
Galactic latitudes that were observed in the Hubble Space Telescope
Snapshot Survey to an average limiting apparent magnitude of V =
21.4. There are 166 fields that contain quasars selected in radio,
X-ray, and color-excess surveys. This sample of 273 stars is free of
selection bias with respect to the density of stars. To within the
Poisson errors, the total counts and magnitude distribution of this
unbiased sample are in agreement with the Bahcall-Soneira model. The
angular distribution of the faint stars favors, at the 2 σ level,
a somewhat steeper disk luminosity function and a smaller spheroid
main-sequence normalization than given by the model. The sample does not
have enough statistical power to distinguish between the two-component
Bahcall-Soneira model and the three-component model first proposed
by Gilmore & Reid, which contains a thick disk. The statistical
power of the survey would increase ~15 fold if colors were obtained
for the stars: the data probe the main sequences of the disk, thick
disk, and spheroid and these three components are well separated in
color. Models with and without a thick disk could then be distinguished
at the 6 sigma level. The HST Snapshot Survey includes an additional
284 fields, 279 of which are centered on quasars that were selected by
objective-prism surveys. These 279 fields are expected to show and do
exhibit bias against bright stars, making them unsuitable for testing
Galactic models. There is a zone of avoidance surrounding quasars
identified by objective-prism techniques which should be taken into
account when determining the distribution properties of these quasars.
Title: The Hubble Space Telescope Quasar Absorption Line Key
Project. III. First Observational Results on Milky Way Gas
Authors: Savage, Blair D.; Lu, Limin; Bahcall, John N.; Bergeron,
Jacqueline; Boksenberg, Alec; Hartig, George F.; Jannuzi, Buell T.;
Kirhakos, Sofia; Lockman, Felix J.; Sargent, W. L. W.; Schneider,
Donald P.; Turnshek, David; Weymann, Ray J.; Wolfe, Arthur M.
Bibcode: 1993ApJ...413..116S
Altcode:
We report on absorption by Milky Way disk and halo gas seen in Quasar
Absorption Line Key Project measurements of 15 quasars obtained with
the Faint Object spectrograph (FOS) of the Hubble Space Telescope
(HST). The measurements extend from 1150 to 3270 A for four objects
and from 1600 to 3270 A for 11 objects and have a velocity resolution
(FWHM) of 220-240 km s^-1^ and signal-to-noise ratio of typically 25
per resolution element. The data processing techniques are presented in
Key Project Papers I and II. Milky Way absorption lines comprise 44%
of all absorption lines found in the first group of 13 Key Project
spectra. The Milky Way lines observed in the highest quality data
for 3C 273 and H 1821+643 include lines from H I, C II, C II^*^,
C IV, O I, N I, Mg I, Mg II, Al II, Al III, Si II, Si III, Si IV,
S II, Mn II, Fe II, and Zn II. Strong singly ionized metal lines of
Fe II λλ2600.17 and 2586.65 and Mg II λλ2796.35 and 2803.53 are
detected in all the spectra. High-quality H I 21 cm emission spectra
are used to make small adjustments to the FOS wavelength scale to
bring the UV data onto an LSR velocity system. The strong metal lines
of Fe II and Mg II permit a sensitive search for metal-line analogs
to the high-velocity clouds seen in H I 21 cm emission. Toward three
quasars we detect resolved, very high negative velocity (v < -
250 km s^-1^) metal-line absorption. Toward four quasars we detect
blended high negative velocity absorption (-250 km s^-1^ < v <
- 100 km s^-1^). Therefore, seven of 15 sight lines observed in this
limited sample exhibit high-velocity or very high velocity metal-line
absorption. Lower limits to the Mg-to-H abundance ratio of 0.059,0.12,
and 0.32 times the solar abundance are obtained for the three detections
of very high velocity Mg II absorption toward PKS 2251 + 11, PG
0043 + 039, and 3C 454.3, respectively. However, cloud clumping may
influence this result, since the H I reference column density from 21
cm emission measurements is obtained with a 21' beam. The sight-line
to PG 1259 + 593 reveals absorptions in the lines of Mg II, Fe II,
C II, and Si II which are in part due to high-velocity cloud Complex
C III. Two sight lines (H1821 + 643 and 3C 351) which extend through
the warped outer Galaxy exhibit strong absorption by singly ionized
metals (C II, Si II, Fe II, Mg II) and highly ionized gas (C IV) at
velocities corresponding to absorption in the outer Galaxy. Combining
our measurements of C IV with data from the literature, we derive
a Galactic C IV exponential scale height of 4.9 kpc and a midplane
density of 7.1 x 10^-9^ atoms cm^-3^. However, the C IV distribution is
so patchy that the measurements are found to be equally well fitted by
a spherical halo model with a Galactocentric exponential scale length
of 6.9 kpc. A comparison of absorption in high-redshift damped Lyα
systems with the absorption produced by the Milky Way shows that an
appreciable fraction of the damped Lyα absorption-line systems have
mixed ionization absorption-line characteristics roughly similar to that
found for six sight lines through the Milky Way disk and halo. Since
the low-ionization lines are highly saturated, this similarity does
not imply similar abundances in the neutral and weakly ionized gas but
instead probably suggests a similarity in the kinematical behavior of
the different absorbing media.
Title: Hydrogen and Metal Absorption Lines in PKS 0405-123 From the
Halos of Low Redshift Galaxies
Authors: Spinrad, Hyron; Filippenko, Alexei V.; Yee, H. K.; Ellingson,
Erica; Blades, J. C.; Bahcall, John N.; Jannuzi, Buell T.; Bechtold,
Jill; Dobrzycki, Adam
Bibcode: 1993AJ....106....1S
Altcode:
Hubble Space Telescope ultraviolet spectra and ground-based optical
spectra of the bright quasar PKS 0405 - 123 are used to identify two
absorption-line systems probably produced by the halos of foreground
galaxies. The quasar lies in a rich galaxy field. Loose groups
of galaxies are present in the field at <z_1_> = 0.1669 and
<z_2_> = 0.3519. Ly α, C IV λ1549, and probably Mg II λ2798
resonance lines are detected in an absorption system at z = 0.1670. An
absorption system consisting of only Ly α is observed at z = 0.3516. We
cannot be completely certain which foreground galaxy is responsible
for the metal line absorption system at z_1_. A likely candidate is
a large, luminous, early-type spiral 40" (projected distance 78h^-1^
kpc) to the east of the quasar. However, the origin of the z_1_ system
could possibly be a small, undetected galaxy more precisely aligned
along our line of sight to PKS 0405 - 123, or a very faint galaxy
whose redshift has not yet been measured.
Title: The Hubble Space Telescope Quasar Absorption Line Key
Project. II. Data Calibration and Absorption-Line Selection
Authors: Schneider, Donald P.; Hartig, George F.; Jannuzi, Buell T.;
Kirhakos, Sofia; Saxe, David H.; Weymann, Ray J.; Bahcall, John N.;
Bergeron, Jacqueline; Boksenberg, Alec; Sargent, W. L. W.; Savage,
Blair D.; Turnshek, David A.; Wolfe, Arthur M.
Bibcode: 1993ApJS...87...45S
Altcode:
We present the observational and data processing aspects of the Hubble
Space Telescope Quasar Absorption Line Key Project. Topics discussed
include the observational technique, calibration of the data, software
that simulates the data, the automated procedure used to identify and
characterize the absorption features, and the determination of the
sensitivity limits of the survey.
Title: The Hubble Space Telescope Quasar Absorption Line Key
Project. I. First Observational Results, Including Lyman-Alpha and
Lyman-Limit Systems
Authors: Bahcall, John N.; Bergeron, Jacqueline; Boksenberg, Alec;
Hartig, George F.; Jannuzi, Buell T.; Kirhakos, Sofia; Sargent,
W. L. W.; Savage, Blair D.; Schneider, Donald P.; Turnshek, David A.;
Weymann, Ray J.; Wolfe, Arthur M.
Bibcode: 1993ApJS...87....1B
Altcode:
We present spectra for a total of 37 quasars with small and
moderate redshifts; the quasars were observed with the Faint Object
Spectrograph of the Hubble Space Telescope. The spectra are obtained
either at a resolution of R = 1300 (hereafter "higher resolution")
or a resolution of r = 180 (hereafter "lower resolution"). We report
new higher resolution measurements of the absorption lines in the
ultraviolet spectra of 11 quasars with emission-line redshifts that
lie between 0.3 and 1.0. Improved reductions are provided for higher
resolution observations of two additional small-redshift quasars
observed as part of the Guaranteed Time observational program. These
observations cover all or part of the wavelength range 1180-3270 A in
the observed frame. In addition, we present lower dispersion spectra
(R = 180, wavelength range 1150-2430 A) obtained for 24 objects with
redshifts between 0.5 and 1.4. Calibrated spectra and continuum fits
are shown for each object. A well-defined sample of absorption lines
was constructed algorithmically from all of the higher resolution data;
the detection limit is expressed in terms of a limiting equivalent width
as a function of wavelength. A total of 358 lines are selected by the
software in the higher resolution spectra. Time-dependent flat-field
features represent the most serious and difficult-to-quantify source
of systematic errors. The identifications of interstellar and of
extragalactic lines were made in the higher resolution spectra with
the aid of software that utilizes the detection limit as a function of
wavelength and the known atomic properties of cosmologically abundant
ions. A total of 104 extragalactic Lyα systems are identified, of
which nine are found at the same redshifts as metal-line systems. The
absorption lines that are not identified Galactic interstellar features
or extragalactic metal lines are not uniformly distributed; their
line density is more than 10 times larger within (rather than outside)
the region accessible to extragalactic hydrogen absorption, providing
statistical support for the identifications of Lyα systems. The local
number density of Lyα systems with rest equivalent widths larger
than 0.32 A and without detected metal lines is (dN/dz)_0_~15.1 +/- 2
Lyα systems per unit redshift, if the local Lyα systems are members
of the same population as the previously observed large-redshift
Lyα lines (i.e., the evolutionary parameter is fixed at γ = 0.75,
and the assumed exponential distribution of equivalent widths is
characterized by W^*^ = 0.32 A). If γ and W^*^ are allowed to vary,
then (dN/dz)_0_~ 17.7 +/- 4.3 Lyα systems per unit redshift with γ =
0.30 +/- 0.62 and W^*^ = 0.22 +/- 0.02 A. The two-point correlation
function of the velocity splittings does not show statistically
significant evidence of clumping. A sample at least 3 times larger
than the one analyzed in this paper would be required to test the
hypothesis that Lyα absorption systems observed at small redshifts
are clustered like galaxies. The spectra of 29 quasars have been
searched algorithmically for the existence of Lyman-limit systems. A
total of 10 Lyman-limit systems with an optical depth greater than
0.4 were identified. The number density of such systems at redshifts
between 0.4 and 1.4 in our sample is (dN/dz)_LLS_ = 0.8(1+z)^0.5^ for
a nonevolving population in a q_0_ = 0.5 universe and (dN/dz)_LLS_
= 0.3(1 + z)^2.4^ if they evolve as rapidly as Lyα clouds observed
at large redshifts. A search for damped Lyα lines revealed only one
candidate line, in the spectrum of PKS 2251+11, among the spectra of
the 36 quasars that were studied. The paucity of damped Lyα lines
at small and moderate redshifts shows that the number density of
damped absorption systems decreases with decreasing redshift. Of
the observed lines, 44% are identified with Galactic interstellar
features, 47% with extragalactic absorption systems, and 9% are
unidentified. Eleven extragalactic C IV doublets are detected. The
incidence of C IV absorption per unit redshift at <z> ~ 0.3 and
with W_rest_(λ1548) >= 0.3 A is dN/ dz = 0.9 +/- 0.4, significantly
lower than the value found at higher redshifts. No obvious correlation
is found between radio power of the quasars and the seven occurrences
of associated absorption. Three individual absorption systems are of
special interest: a broad absorption line system in the spectrum of
PG 0043+039; a strong, apparently broad high-excitation associated
absorption system in 3C 351; and a rich, high-excitation intervening
metal-line system in PKS 2145_06 which has 16 identified lines.
Title: G-Modes and the Solar Neutrino Problem
Authors: Bahcall, John N.; Kumar, Pawan
Bibcode: 1993ApJ...409L..73B
Altcode: 1993hep.ph....3229B
We show that low-order g-modes with large enough amplitudes to
affect significantly the solar neutrino fluxes would produce surface
velocities that are $10^4$ times larger than the observed upper
limits and hence are ruled out by existing data. We also demonstrate
that any large-amplitude, short-period oscillations that grow on a
Kelvin-Helmholtz time scale will require, to affect solar neutrino
fluxes, a large amount of energy (for g-modes, $10^9$ times the energy
in the observed $p-$ mode oscillations) and a tiny amount of dissipation
(for g-modes, $10^{-8}$ the dissipation rate of the $p$-modes).
Title: The Hubble Space Telescope Snapshot Survey. IV. A Summary of
the Search for Gravitationally Lensed Quasars
Authors: Maoz, D.; Bahcall, J. N.; Schneider, D. P.; Bahcall, N. A.;
Djorgovski, S.; Doxsey, R.; Gould, A.; Kirhakos, S.; Meylan, G.;
Yanny, B.
Bibcode: 1993ApJ...409...28M
Altcode:
We report the concluding results of the HST Snapshot Survey for
gravitationally lensed quasars. New observations of 153 high-luminosity
z > 1 quasars are presented, bringing to 498 the total number of
quasars observed in the survey. The new observations do not reveal new
candidates for gravitational lensing. We present tables summarizing all
of the snapshot observations, with measured V-magnitudes, accurate to
0.1 mag, for each of the quasars successfully observed. The tables are
available on request in machine-readable form. The observed frequency of
lensing of quasars into multiple images is 3-6 out of 502, depending on
whether one counts candidates that are not yet securely confirmed and
cases in which clusters play a role. This frequency is in the range
predicted by calculations with a vanishing cosmological constant,
assuming galaxies can be modeled by unevolving isothermal spheres
dominated in their centers by dark matter. The observed frequency is an
order of magnitude lower than expected in such models when the universe
is strongly dominated by a cosmological constant. This conclusion is,
however, sensitive to the model assumptions and to the precise number
of actual lensed quasars.
Title: Recent work on standard solar models
Authors: Bahcall, John N.
Bibcode: 1993NuPhS..31..125B
Altcode: 1992hep.ph...11280B
Recent results on standard solar models are reviewed. I shall
summarize briefly three of the themes that I stressed at the Neutrino
'92 Conference: 1) Different solar model codes give the same answers
when the same input data are used; 2) Improved calculations of standard
solar models include helium diffusion, the Livermore radiative opacity,
the meteoritic iron abundance, and a variety of other corrections; and
3) There are a few basic rules that should be followed in using standard
solar models. At the Neutrino '92 Conference, I reviewed in more detail
the recent work on standard solar models by Marc Pinsonneault and
myself. This work has by now appeared in print (Rev. Mod. Phys. 64,
885, 1992, hereafter Paper I, and ApJ Letters, 69, 717, 1992, Paper
II). Therefore, there is no need for me to repeat the details here.
Title: Erratum - Globular Cluster Photometry with the Hubble Space
Telescope - Part One - Description of the Method and Analysis of
the Core of 47-TUCANAE
Authors: Guhathakurta, P.; Yanny, B.; Schneider, D. P.; Bahcall, J. N.
Bibcode: 1993AJ....105.1607G
Altcode:
No abstract at ADS
Title: The Ultraviolet Absorption Spectrum of the Quasar PKS 0405-12
and the Local Density of Lyman-Alpha Absorption Systems
Authors: Bahcall, John N.; Jannuzi, Buell T.; Schneider, Donald P.;
Hartig, George F.
Bibcode: 1993ApJ...405..491B
Altcode:
A sample of 32 absorption lines has been identified in the ultraviolet
spectrum of the z = 0.57 quasar PKS 0405 - 12. The observations were
obtained using three R = 1300 gratings of the Faint Object Spectrograph
of the Hubble Space Telescope. The data cover the wavelength range
1190- 3260 A. The sample was constructed by requiring that all
included lines have a measured equivalent width greater than the
wavelength-dependent 3 σ detection limit for unresolved lines. Sixteen
of the absorption features are due to Galactic interstellar lines. There
are 10 extragalactic Lyα absorption lines in the complete sample,
all with observed equivalent widths greater than or equal to 0.40 A;
three of the Lyα lines have Lyβ counterparts. The number of Lyα
lines observed in the spectrum of PKS 0405-12 is within 1 σ of the
number predicted on the basis of previous HST observations of 3C 273 and
of H1821 +643. Combining the HST observations of 3C 273, H1821 +643,
and PKS 0405-12, we estimate the local number density of Lyα systems
with rest equivalent widths larger than 0.32 A to be dN/dZ(W_res_
>= 0.32 A) ~ 15 + 4 Lyα lines per unit redshift. Ground-based
images reveal a rich field of galaxies in the direction of PKS 0405 -
12, including many galaxies with the brightnesses and sizes expected
if they belong to a cluster associated with the quasar. The quasar
spectrum does not show any evidence for absorption at the redshift of
the emission lines, indicating a covering factor of less than unity
for the halos of galaxies in the cluster around PKS 0405-12,
Title: Do solar-neutrino experiments imply new physics\?
Authors: Bahcall, John N.; Bethe, H. A.
Bibcode: 1993PhRvD..47.1298B
Altcode: 1992hep.ph...12204B
None of the 1000 solar models in a full Monte Carlo simulation
is consistent with the results of the chlorine or the Kamiokande
experiments. Even if the solar models are forced artificially to have a
8B neutrino flux in agreement with the Kamiokande experiment,
none of the fudged models agrees with the chlorine observations. The
GALLEX and SAGE experiments, which currently have large statistical
uncertainties, differ from the predictions of the standard solar model
by 2σ and 3σ, respectively.
Title: An HST Study of Blue Stragglers in 47 TUC and M15
Authors: Guhathakurta, P.; Yanny, B.; Schneider, D. P.; Bahcall, J. N.
Bibcode: 1993ASPC...53...60G
Altcode: 1993blst.conf...60G
No abstract at ADS
Title: Stellar Photometry in the Core of 47-TUCANAE Using HST
Authors: Guhathakurta, P.; Yanny, B.; Schneider, D. P.; Bahcall, J. N.
Bibcode: 1993ASPC...50..303G
Altcode: 1993sdgc.proc..303G
No abstract at ADS
Title: Uncertainties in the calculated solar neutrino fluxes
Authors: Bahcall, J. N.
Bibcode: 1993paas.conf...63B
Altcode:
No abstract at ADS
Title: HST Observations of Globular Cluster Cores
Authors: Yanny, B.; Guhathakurta, P.; Schneider, D. P.; Bahcall, J. N.
Bibcode: 1993ASPC...50..275Y
Altcode: 1993sdgc.proc..275Y
No abstract at ADS
Title: The Hubble Space Telescope Snapshot Survey. III. Further
Observations in Search of Gravitationally Lensed Quasars
Authors: Maoz, D.; Bahcall, J. N.; Doxsey, R.; Schneider, D. P.;
Bahcall, N. A.; Lahav, O.; Yanny, B.
Bibcode: 1993ApJ...402...69M
Altcode:
We present new HST Snapshot Survey observations of 163 high-luminosity z
> 1 quasars, bringing the total number observed to date in the survey
to 347 quasars. Each exposure was searched for evidence of gravitational
lensing. Among the newly observed quasars, six have additional point
sources at separations of 2"-6", but in all six cases ground-based data
indicate that gravitational lensing is not involved. No point sources
were found at smaller separations. Counting the one new lens candidate
the survey has uncovered (1208+1011, described in previous papers)
and the known lenses excluded from the sample, the observed frequency
of lensing of quasars by galaxies is 5/351. This frequency is in the
range predicted by models with a vanishing cosmological constant, but
an order of magnitude lower than expected in models strongly dominated
by a cosmological constant. The HST pointing accuracy under gyroscope
control has improved and is now 14"+/- 9" (mean and rms).
Title: Summary Talk: International Symposium on Neutrino Astrophysics,
Takayama/Kamioka (10/'92)
Authors: Bahcall, John
Bibcode: 1992hep.ph...12262B
Altcode:
Contents: 1. The Conference 2. Solar Neutrinos -A. Operating Experiments
-B. New Funded Experiments -C. Are Solar Neutrino Fluxes Time
Dependent? -D. Have $pp$ Neutrinos Been Detected? -E. Is Directionality
Required for Astronomical Observations? -F. Is There a Solar Neutrino
Problem? -G. What Have We Learned? 3. Supernova Neutrinos 4. Atmospheric
Neutrinos 5. High-Energy Neutrinos 6. Our Field Is Flourishing
Title: Radial Density Profiles in the Centers of 47 TUC and M15 from
HST Images
Authors: Yanny, B.; Guhathakurta, P.; Schneider, D. P.; Bahcall, J. N.
Bibcode: 1992AAS...18110802Y
Altcode: 1992BAAS...24.1294Y
Hubble Space Telescope Planetary Camera (HST/PC) images of the
centers of the dense Galactic globular clusters 47 Tuc and M 15 are
presented. We study the radial dependence of the surface density of
post-main sequence stars and the surface brightness of the diffuse
light of faint unresolved stars below the main sequence turnoff. The
radial profile of 47 Tuc is fit well by a King model with core radius
r_c=23'' (0.5 pc). The extremely high density of stars near the center
of post-core collapse cluster M 15 and the broad wings of the point
spread function (PSF) caused by spherical aberration in HST's primary
mirror combine to make stellar photometry a painstaking process A
technique, specially designed to work in crowded fields, has been
used to derive an empirical PSF model and make a fit to the stellar
images. Accurate fitting and subtraction of the light of bright red
giant stars and estimating the incompleteness as a function of radius
and magnitude are crucial to this study. Realistic simulated images
have been constructed and analyzed for this purpose. We compare the M
15 data to simulations with a small, but finite core (r_c=2''=0.1pc)
and those with mild central cusps (surface density ~ r(-alpha ) ,
where alpha =0.5-0.8).
Title: Globular Cluster Photometry with HST: Color-Mag Diagrams in
the Dense Cores of 47 TUC and M15
Authors: Guhathakurta, P.; Yanny, B.; Schneider, D. P.; Bahcall, J. N.
Bibcode: 1992AAS...181.4307G
Altcode: 1992BAAS...24Q1188G
We present accurate (sigma ~ 0.1 mag), multi-color photometry of
stars in the cores of two of the densest known Galactic globular
clusters, 47 Tuc and M15, using images obtained with the Hubble Space
Telescope's Planetary Camera (HST/PC). Despite the spherical aberration
in HST's primary mirror, the high angular resolution of the PC images
makes it possible to construct reliable color-magnitude diagrams of
post-main sequence stars even in the most crowded portions of these
clusters. This task has proven impossible from the ground in the best
of seeing conditions (FWHM ~ 0.5''). We have developed a technique that
constructs an empirical model of the stellar point spread function (PSF)
from a PC image of a globular cluster core. The technique corrects
for saturation in the stellar cores (caused by the limited dynamic
range of the CCD detector) and attempts to track the variation in
the shape of the PSF across the image. Detailed knowledge of the PSF
is essential in order to do crowded field stellar photometry; note,
the low level wings of the PSF extend beyond a radius of 2.5'' while
the average projected separation between stars in these cluster cores
is less than 1''. The PSF modeling and stellar photometry technique
has been tested and calibrated with the help of realistic simulated
images. Color-magnitude diagrams (U-V and V-I versus V) of 47 Tuc
and M15 reveal a few dozen blue straggler stars within the central
1 arcmin(2) of each cluster. The blue stragglers are more centrally
concentrated than the average post-main sequence star and are consistent
with having masses equal to 2m_turnoff. The ratio of the number of
bright red giant branch stars to horizontal branch stars does not vary
with radius within the inner 1' of 47 Tuc. In M15, that ratio declines
near the cluster center, consistent with the hypothesis that the red
giant envelopes have been destroyed in this region of extremely high
stellar density.
Title: Faint Object Spectrograph Observations of the Large-Redshift
Gravitational Lens Candidate 1208+1011
Authors: Bahcall, John N.; Hartig, George F.; Jannuzi, Buell T.;
Maoz, Dan; Schneider, Donald P.
Bibcode: 1992ApJ...400L..51B
Altcode:
We report HST spectroscopic observations of the z = 3.8 gravitational
lens candidate 1208+1011. Low-dispersion (R = 200) Faint Object
Spectrograph data, covering the wavelength range 3700-7800 A, were
obtained for each of the two components (V ~18.3 and 19.8 mag) and
for a comparison (blank) field; the fainter component and the blank
field are both separated by 0.47" from the brighter image. The spectra
of both components possess strong Lyα/N V and O VI/Lyβ emission
lines at a redshift of 3.8 as well as a number of similar absorption
features. Both components have a ratio of the equivalent widths of the O
VI complex to the Lyα complex much larger than the typical value seen
in large-redshift quasars. There are small differences in the measured
profiles of the Lyα and O VI/Lyβ emission lines of the images. These
differences could be caused by absorption along different paths to
a single lensed object, by unequal imaging of extended emissions,
by systematic measuring errors, or by intrinsic differences in two
nearly identical neighboring quasars.
Title: Element Diffusion in the Solar Interior
Authors: Thoul, A. A.; Bahcall, J. N.; Loeb, A.
Bibcode: 1992AAS...181.8106T
Altcode: 1992BAAS...24.1253T
We study the diffusion of helium and other heavy elements in the
solar interior, using the flow equations developed by Burgers (1969)
for a multi-component fluid. The set of equations is solved exactly,
including the residual heat flow terms. No approximation is made about
the relative concentrations and no restriction is placed on the number
of elements considered. For helium diffusion, we compare our results
with those obtained by Bahcall and Loeb (1990) using a simplified
treatment with heat flows neglected. We find that the inclusion of
the residual heat flow terms leads to a significant increase in the
helium diffusion velocity. However, we also find that the temperature
and charge-dependence of the Coulomb logarithm has the opposite effect,
leading to a decrease in the helium diffusion velocity. By coincidence,
the two effects partially cancel each other out throughout most of
the solar interior. Our complete treatment of element diffusion could
be directly incorporated in a standard stellar evolution code, but,
for convenience, we also give simple analytical fits of our numerical
results. Burgers, J.M. 1969, Flow equations for composite gases(Academic
Press, New York). Bahcall, J.N., and Loeb, A. 1990, Ap.J.,360, 267.
Title: Globular Cluster Photometry With the Hubble Space
Telescope. I. Description of the Method and Analysis of the Core of
47 TUC
Authors: Guhathakurta, Puragra; Yanny, Brian; Schneider, Donald P.;
Bahcall, John N.
Bibcode: 1992AJ....104.1790G
Altcode:
Accurate photometry for individual post-main-sequence stars in the core
of the Galactic globular cluster 47 Tuc is presented and analyzed using
an empirical point spread function model and Monte Carlo simulations. A
V vs. V-I color-magnitude diagrams is constructed which shows several
distinct stellar types, including RGB and HB stars. Twenty-four blue
straggler stars are detected in 47 Tuc, more concentrated toward the
center of the cluster than the giants. This supports the hypothesis is
that the stragglers are either coalesced stars or members of binary
systems that are more massive than single stars. The radial profile
of the projected stellar density is flat in the central region of 47
Tuc with a core radius of 23 +/- 2 arcsec. No signature of a collapsed
core is evident. The observed radial cumulative distribution of stars
rules out the presence of a massive compact object in the center.
Title: The Near-Ultraviolet Spectrum of Markarian 205
Authors: Bahcall, John N.; Jannuzi, Buell T.; Schneider, Donald P.;
Hartig, George F.; Jenkins, Edward B.
Bibcode: 1992ApJ...398..495B
Altcode:
We report measurements of the absorption and of the emission lines
between 1600 and 3200 A in the spectrum of the nearby AGN Markarian 205
(z = 0.071), which lies at a projected distance of 3 kpc (H_0_= 100 km
s^-1^) from the nucleus of the nearby barred spiral galaxy NGC 4319 (z
= 0.0047). The results were obtained using high-resolution (R = 1300)
observations with the Faint Object Spectrograph of the Hubble Space
Telescope. A total of 15 absorption lines, 13 of which are produced
by Galactic gas, and four AGN emission lines are detected. Two of the
absorption lines, the Mg II resonant doublet, are produced by gas
in the intervening galaxy NGC 4319. This is the first detection of
absorption due to intervening gas in this famous quasar-galaxy pair.
Title: Standard solar models, with and without helium diffusion,
and the solar neutrino problem
Authors: Bahcall, J. N.; Pinsonneault, M. H.
Bibcode: 1992RvMP...64..885B
Altcode:
We first show that, with the same input parameters, the standard solar
models of Bahcall and Ulrich; of Sienkiewicz, Bahcall, and Paczyński
of Turck-Chièze, Cahen, Cassé, and Doom; and of the current Yale code
all predict event rates for the chlorine experiment that are the same
within +/-0.1 SNU (solar neutrino units), i.e., approximately 1% of
the total calculated rate. We then construct new standard solar models
using the Yale stellar evolution computer code supplemented with a more
accurate (exportable) nuclear energy generation routine, an improved
equation of state, recent determinations of element abundances, and the
new Livermore (OPAL) opacity calculations. We evaluate the individual
effects of different improvements by calculating a series of precise
models, changing only one aspect of the solar model at a time. We
next add a new subroutine that calculates the diffusion of helium with
respect to hydrogen with the aid of the Bahcall-Loeb formalism. Finally,
we compare the neutrino fluxes computed from our best solar models
constructed with and without helium diffusion. We find that helium
diffusion increases the predicted event rates by about 0.8 SNU, or 11%
of the total rate, in the chlorine experiment; by about 3.5 SNU, or 3%,
in the gallium experiments; and by about 12% in the Kamiokande and SNO
experiments. The best standard solar model including helium diffusion
and the most accurate nuclear parameters, element abundances, radiative
opacity, and equation of state predicts a value of 8.0+/-3.0 SNU for the
37Cl experiment and 132+21-17 SNU for
the 71Ga experiment. The quoted errors represent the total
theoretical range and include the effects on the model predictions of
3σ errors in measured input parameters. All 15 calculations since 1968
of the predicted rate in the chlorine experiment given in this series
of papers are consistent with both the range estimated in the present
work and the 1968 best-estimate value of 7.5+/-2.3 SNU. Including
the effects of helium diffusion and the other improvements in
the description of the solar interior that are implemented in this
paper, the inferred primordial solar helium abundance is Y=0.273. The
calculated depth of the convective zone is R=0.707Rsolar,
in agreement with the value of 0.713Rsolar inferred by
Christensen-Dalsgaard, Gough, and Thompson from a recent analysis
of the observed p-mode oscillation frequencies. Including helium
diffusion increases the calculated present-day hydrogen surface
abundance by about 4%, decreases the helium abundance by approximately
11%, and increases the calculated heavy-element abundance by about
4%. In the Appendix, we present detailed numerical tables of our best
standard solar models computed both with and without including helium
diffusion. In the context of the MSW (Mikheyev-Smirnov-Wolfenstein)
or other weak-interaction solutions of the solar neutrino problem,
the numerical models can be used to compute the influence of the matter
in the sun on the observed neutrino fluxes.
Title: Star Counts From The HST SnapShot Survey
Authors: Gould, A.; Bahcall, J. N.; Maoz, D.
Bibcode: 1992AAS...181.3809G
Altcode: 1992BAAS...24.1179G
No abstract at ADS
Title: Hubble Space Telescope Wide Field Camera Imaging of the
Gravitational Lens 2237+0305
Authors: Rix, Hans-Walter; Schneider, Donald P.; Bahcall, John N.
Bibcode: 1992AJ....104..959R
Altcode:
Hubble Space Telescope Wide Field Camera images of the gravitational
lens 2237+0305 in the F336W ("U") and F702W ("A") filters are used to
construct models of the system. Positions for the four quasar images,
accurate to +/-0.015", and relative magnitudes in U and R, accurate
to +/-0.06 and 0.04 mag respectively, are determined. The upper limits
on the observed brightness of the fifth image are found to be <~7%
of the brightest quasar image. The long "color baseline," from R to U,
permits good estimates of the differential image reddening. With M/L as
the only free parameter describing the lens and two further parameters
describing the position of the quasar in the source plane, the eight
quasar image positions can be reproduced to within ~0.03" (or 2.5% of
their separations); at the same time the three relative brightnesses can
be reproduced to within factors of 1.5. The total image amplification is
well constrained by these models: a factor of 18.5+/-2. This modeling
assumes only that the surface mass density of the lens galaxy is
proportional to the observed surface brightness. The mass of the
lens inside 0.9" is found to be 1.08+/-0.02X10^10^M_sun_h^-1^_100_
corresponding to a mass-to-light ratio in B of 12.3h_100_. This
M/L estimate agrees with values obtained from stellar dynamics
for other elliptical galaxies. The mass in the inner 500h^-1^_100_
pc is constrained by these phenomenological models to within +/-2%,
a more precise mass determination than for any other known bulge or
elliptical. A comparison of predictions from this mass model with the
measured central velocity dispersion yields a distance independent
agreement to within 10%, assuming isotropic velocity dispersions. The
influence of the mass associated with the Mg II absorber at z = 0.9 on
the lensing appears to be unimportant. The detailed agreement of the
lens model with the observations of 2237+0305, achieved by using the
lens equations of general relativity and the cosmological interpretation
of quasar redshifts, provides confirmation of these standard theories.
Title: The Ultraviolet Absorption Spectrum of the Quasar H1821+643
(z = 0.297)
Authors: Bahcall, John N.; Jannuzi, Buell T.; Schneider, Donald P.;
Hartig, George F.; Green, Richard F.
Bibcode: 1992ApJ...397...68B
Altcode:
We report measurements of the absorption lines in the ultraviolet
spectrum of the nearby luminous quasar H1821+643 (z = 0.297). The
results were obtained using high-resolution observations with the
faint object spectrograph of the Hubble Space Telescope. A total of
51 absorption lines and a number of emission features were detected
between 1190 and 3260 A. A complete sample of 38 absorption lines was
constructed with the detection limit defined in terms of a limiting
equivalent width as a function of wavelength. The identifications with
interstellar and with extragalactic lines were made with the aid of
software that utilizes the limiting detection sensitivity as a function
of wavelength and the known atomic properties of cosmologically abundant
ions. The majority of the absorption features are Galactic interstellar
lines. The interstellar absorption lines and the quasar emission lines
present in the spectrum of H1821+643 are similar to the lines observed
in other small-redshift quasars. There are five strong extragalactic
Lyα absorption lines in the spectrum of H1821+643, all with observed
equivalent widths greater than 0.45 A. Combining the HST observations
of 3C 273 and H1821+643, we estimate the local number density of
Lyα systems with rest equivalent widths larger than 0.32 A to be
(dN/dz)_0_~13 +/- 5 Lyα lines per unit redshift. Some of the Lyα
systems with redshifts significantly different from the quasar appear
to be associated with galaxies or with clusters of galaxies. Two of the
Lyα lines have the same redshift within c{DELTA}z = 400 km s^-1^ as
that of an emission-line galaxy located at a projected separation from
the quasar of approximately 90 kpc (H_0_ = 100 km s^-1^ Mpc^-1^). This
system at z = 0.226 is part of a triplet of Lyα lines that have a total
redshift separation of cz = +/- 450 km s^-1^. There is also statistical
evidence that some of the Lyα systems are clumped more than would be
expected if they were distributed randomly along the line of sight
to H1821+643. Many of the Lyα systems observed at small redshifts
may be associated with large hydrogen halos of galaxies or groups and
clusters of galaxies. One of the Lyα systems in H1821+643 occurs at an
absorption redshift approximately equal to the emission-line redshift
of the quasar and is accompanied by absorption from the C IV and O
VI doublets; this is an example of what has been called associated
absorption, z_abs_~z_em, for large-redshift quasars. No lines from
low-ionization ions are detected in this system. The observations
of H1821+643 fail to confirm previous suggestions that associated
absorption is correlated with strong radio emission (H1821+643 is
radio-quiet) or with low optical luminosity (H1821+643 is comparable
in luminosity to 3C 273). The observations are consistent with two
previously proposed conjectures, that associated absorption is produced
in clusters of galaxies containing the quasars or that the absorption
is produced in the gas associated with the quasars.
Title: Helium Diffusion in the Sun
Authors: Bahcall, J. N.; Pinsonneault, M. H.
Bibcode: 1992ApJ...395L.119B
Altcode:
We calculate improved standard solar models using the new Livermore
(OPAL) opacity tables, an accurate (exportable) nuclear energy
generation routine which takes account of recent measurements and
analyses, and the recent Anders-Grevesse determination of heavy element
abundances. We also evaluate directly the effect of the diffusion of
helium with respect to hydrogen on the calculated neutrino fluxes,
on the primordial solar helium abundance, and on the depth of the
convective zone. Helium diffusion increases the predicted event rates by
about 0.8 SNU, or 11 percent of the total rate, in the chlorine solar
neutrino experiment, by about 3.5 SNU, or 3 percent, in the gallium
solar neutrino experiments, and by about 12 percent in the Kamiokande
and SNO solar neutrino experiments. The best standard solar model
including helium diffusion and the most accurate nuclear parameters,
element abundances, and radiative opacity predicts a value of 8.0 SNU
+/- 3.0 SNU for the C1-37 experiment and 132 +21/-17 SNU for the Ga -
71 experiment, where the uncertainties include 3 sigma errors for all
measured input parameters.
Title: Monte Carlo exploration of Mikheyev-Smirnov-Wolfenstein
solutions to the solar neutrino problem
Authors: Shi, X.; Schramm, D. N.; Bahcall, J. N.
Bibcode: 1992PhRvL..69..717S
Altcode:
We explore the impact of astrophysical uncertainties on the
Mikheyev-Smirnov-Wolfenstein (MSW) solution by calculating the allowed
MSW solutions for 1000 different solar models with a Monte Carlo
selection of solar model input parameters, assuming a full three-family
MSW mixing. Applications are made to the chlorine, gallium, Kamiokande,
and Borexino experiments. The initial GALLEX result limits the mixing
parameters to the upper diagonal and the vertical regions of the MSW
triangle. We also calculate the expected event rates in the Borexino
experiment assuming the MSW solutions implied by GALLEX.
Title: Accurate Positions and Finding Charts for 528 High-Redshift,
Luminous Quasars
Authors: Schneider, Donald P.; Bahcall, John N.; Saxe, David H.;
Bahcall, Neta A.; Doxsey, Rodger; Golombek, Daniel; Krist, John;
McMaster, Matt; Meakes, Michael; Lahav, Ofer
Bibcode: 1992PASP..104..678S
Altcode:
We present finding charts and J2000 positions accurate to 1" for the 528
high-redshift (z > 1), luminous (M_V < -25.5) quasars investigated
in the Hubble Space Telescope Snapshot Survey. The information was
produced with the Space Telescope Science Institute's Astrometric
Support Program. (SECTION: Galaxies)
Title: Gravitational Lensing of Quasars as Seen by the Hubble Space
Telescope Snapshot Survey
Authors: Maoz, D.; Bahcall, J. N.; Doxsey, R.; Schneider, D. P.;
Bahcall, N. A.; Lahav, O.; Yanny, B.
Bibcode: 1992ApJ...394...51M
Altcode:
As part of the ongoing HST Snapshot Survey, 152 additional high-
luminosity z > 1 quasars were observed, bringing the total to
184 quasars. Each exposure was searched for evidence of gravitational
lensing. Only one quasar among those observed, 1208+1011, is a candidate
lens system with subarcsecond image separation. Six other quasars have
point sources within 6". Ground-based observations of five of these
cases show that the companion point sources are foreground Galactic
stars. The observed lensing frequency, after accounting for known
lenses excluded from the sample, and including 32 quasars observed
from a pilot sample described in a previous paper, is 3/184. The
predicted lensing frequency of the sample is calculated for a variety
of cosmological models. The effect of uncertainties in some of the
observational parameters upon the predictions is discussed. The
observed lensing frequency is consistent with predictions of models
with a zero cosmological constant λ. Assuming the best estimates for
the parameters involved in the calculation, flat cosmologies with λ
> 0.85 can be ruled out at greater than 95% confidence. From the
engineering perspective, we find that the software corrections for
stellar aberration when the telescope is guided on gyroscopes results
in drift rates of 1-2 milliarcseconds s^-1^, about 3 times smaller
than before the correction was implemented. The mean and rms pointing
error under gyro control is 20" +/- 13". We find no correlation of the
drift rate with time, right ascension, declination, or pointing error.
Title: Quasar Absorption Line Survey - Cycle 3 High - Part 3
Authors: Bahcall, John
Bibcode: 1992hst..prop.5225B
Altcode:
PART 3 consists of replacement targets for objects pulled from the
original submission because targets had been previously observed in
other programs. The Absorption Line Survey of bright quasars provides
a homogeneous data base for studying fundamental questions about the
origin and evolution of gaseous systems in the universe. The initial
results determine at small redshifts the number densities of Ly-ALPHA
systems, of metal-lines and extragalactic halos, of Lyman-limit systems,
of associated absorption systems, and the shapes and intensities of
quasar emission lines and spectral energy distributions. The survey
reveals that much of the sky is covered by high or very high velocity
metal-line clouds present in the Galactic halo. A larger sample,
which includes the requested Cycle 3 observations, is required to
answer many important questions. (See abstract_temp for Part 1, P4581)
Title: Quasar Absorption Line Survey - Cycle 3 High - Part 2
Authors: Bahcall, John
Bibcode: 1992hst..prop.5081B
Altcode:
PART 2 consists of replacement targets for objects pulled from the
original submission because targets had been previously observed in
other programs. The Absorption Line Survey of bright quasars provides
a homogeneous data base for studying fundamental questions about the
origin and evolution of gaseous systems in the universe. The initial
results determine at small redshifts the number densities of Ly-ALPHA
systems, of metal-lines and extragalactic halos, of Lyman-limit systems,
of associated absorption systems, and the shapes and intensities of
quasar emission lines and spectral energy distributions. The survey
reveals that much of the sky is covered by high or very high velocity
metal-line clouds present in the Galactic halo. A larger sample,
which includes the requested Cycle 3 observations, is required to
answer many important questions. (See abstract_temp for Part 1, P4581)
Title: Quasar Absorption Line Survey - Cycle 3 High
Authors: Bahcall, John
Bibcode: 1992hst..prop.4581B
Altcode:
The Absorption Line Survey of bright quasars provides a homogeneous
data base for studying fundamental questions about the origin and
evolution of gaseous systems in the universe. The initial results
determine at small redshifts the number densities of Ly-ALPHA systems,
of metal-lines and extragalactic halos, of Lyman-limit systems,
of associated absorption systems, and the shapes and intensities of
quasar emission lines and spectral energy distributions. The survey
reveals that much of the sky is covered by high or very high velocity
metal-line clouds present in the Galactic halo. A larger sample, which
includes the requested Cycle 3 observations, is required to answer many
important questions. For example, what is the correlation function
of Ly-ALPHA systems at small redshifts\? What fraction of the metal,
the Ly-ALPHA, and the Ly-limit systems are associated with galaxies
and what are the characteristic sizes of the outer gaseous regions of
different types of galaxies\? Do absorbing systems show evidence of the
large-scale structure seen with galaxies and clusters of galaxies\? The
observations requested in Cycle 3 will extend the region of coverage
of the Key Project sample from the redshift range of z = 0.0 to 1.0
(Cycles 1& 2) to z = 0.0 to 1.6 (Cycles 1-3). The increase in sample
size will be sufficient to determine, in conjunction with ground-based
observations at large redshifts, the evolution of Ly-ALPHA and of
metal-line systems from early cosmic times to the present epoch.
Title: Hubble Space Telescope Imaging of the Large-Redshift
Gravitational Lens Candidate 1208+1011
Authors: Bahcall, John N.; Maoz, Dan; Schneider, Donald P.; Yanny,
Brian; Doxsey, Rodger
Bibcode: 1992ApJ...392L...1B
Altcode:
Four-color photometry obtained with the Hubble Space Telescope is
consistent with the hypothesis that the light from the quasar 1208+1011
(z = 3.8) is gravitationally lensed. Guided exposures taken with the
HST Planetary Camera resolve the quasar image into two point-source
components separated by 0.476" +/- 0.004". The intensity ratio of
the components is approximately 4:1 in each of four broad-band HST
filters with mean wavelengths of 4352, 5416, 6898, and 8922 A. The
HST photometry, when combined with high-resolution ground-based
spectroscopy, rules out the possibility that the secondary component
is a Galactic star. The limit on additional point sources is 3% of
the brighter image for separations greater than 0.5" from the primary
component and 5% of the brighter component for separations between 0.1"
and 0.5". If the gravitational lens is an ordinary galaxy, it would
not have been detected on the HST images.
Title: The Cluster of Galaxies Associated with the Low-Redshift
Quasar H1821+643
Authors: Schneider, Donald P.; Bahcall, John N.; Gunn, James E.;
Dressler, Alan
Bibcode: 1992AJ....103.1047S
Altcode:
Low resolution spectra have been obtained of eight R~19 mag galaxies
located within 1 arcmin of the low-redshift, high luminosity quasar
H1821 + 643. Six of the eight galaxies belong to a cluster that has the
same redshift, within the observational errors, as the quasar. Five
of the six cluster members have the spectra of early type galaxies;
the spectrum of the sixth cluster member contains Hα, O [III], and
possibly O II emission lines. The other two objects are an emission
line foreground galaxy and a back-ground galaxy. The cluster has
a Galactocentric redshift of 0.299+/- 0.002 and a radial velocity
dispersion of 1050 + 320 km s^-1^. The photometric and spectroscopic
data suggest that H1821 + 643 is associated with a rich cluster of
galaxies.
Title: Local Dark Matter from a Carefully Selected Sample
Authors: Bahcall, John N.; Flynn, Chris; Gould, Andrew
Bibcode: 1992ApJ...389..234B
Altcode:
The precise data obtained by Flynn and Freeman (1991) on K giants
at the south Galactic pole are used to analyze the amount of local
dark matter in which the systematic effects can be modeled easily and
evaluated accurately. The method of Bahcall (1984) is employed to solve
the self-consistent equations for the distribution of dark matter. The
K-giant survey is found to provide significant evidence for disk dark
matter. Taking into account all recognized sources of error using a
statistical test devised by Gould (1989, 1990), a model with no dark
matter is inconsistent with the data at the 86-percent confidence
level. The best-fit P-model (in which dark matter is distributed
proportionally to known matter) has 53 percent more dark matter than
visible matter.
Title: The Snapshot Survey: A Search for Gravitationally Lensed
Quasars with the Hubble Space Telescope
Authors: Bahcall, J. N.; Maoz, D.; Doxsey, R.; Schneider, D. P.;
Bahcall, N. A.; Lahav, O.; Yanny, B.
Bibcode: 1992ApJ...387...56B
Altcode:
In a systematic attempt to find new examples of multiply imaged quasars
that are the result of gravitational lensing, 89 short exposures,
through two filters, of high-luminosity quasars from a well-defined
sample have been obtained with the Hubble Space Telecope's Planetary
Camera. Useful high-resolution images of approximately 30 quasars
have resulted. None of the quasars show evidence of multiple images
due to gravitational lensing. Simulations show that multiple images
with brightness ratios of up to several magnitudes would have been
detected, down to image separations of ~0.1". These results are compared
with lower resolution ground-based surveys and current theoretical
predictions. The Snapshot Survey has uncovered several engineering
problems in the observatory's performance, some of which have already
been corrected. In particular, we find that the large telescope
pointing errors and drift rates are primarily the result of the lack
of correction for stellar aberration when pointing and tracking are
performed solely with gyroscopes. The implications of the possibly low
intrinsic gyro drift rate on future observations are briefly discussed.
Title: A Gravitational Lens Candidate Discovered with the Hubble
Space Telescope
Authors: Maoz, Dan; Bahcall, John N.; Schneider, Donald P.; Doxsey,
Rodger; Bahcall, Neta A.; Filippenko, Alexei V.; Goss, W. M.; Lahav,
Ofer; Yanny, Brian
Bibcode: 1992ApJ...386L...1M
Altcode:
We report evidence for gravitational lensing of the high-redshift (z
= 3.8) quasar 1208+101, observed as part of the Snapshot Survey with
the Hubble Space Telescope Planetary Camera. An HST V image taken on
gyroscopes resolves the quasar into three point-source components,
with the two fainter images having separations of 0.1" and 0.5" from
the central bright component. A radio observation of the quasar with
the Very Large Array at 2 cm shows that, like most quasars of this
redshift, 1208+101 is radio-quiet. Based on positional information
alone, the probability that the observed optical components are chance
superpositions of Galactic stars is small, but not negligible. Analysis
of a combined ground-based spectrum of all three components, using
the relative brightnesses from the HST image, supports the lensing
hypothesis. If all the components are lensed images of the quasar,
the observed configuration cannot be reproduced by simple lens
models. Future HST observations can test the lensing hypothesis for
1208+101.
Title: What do solar models tell us about solar neutrino experiments?
Authors: Bahcall, John N.
Bibcode: 1992AIPC..272.1111B
Altcode: 1992hep.ph...11291B
If the published event rates of the chlorine and Kamiokande solar
neutrino experiments are correct, then the energy spectrum of neutrinos
produced by the decay of 8B in the sun must be different from the energy
spectrum determined from laboratory nuclear physics measurements. This
change in the energy spectrum requires physics beyond the standard
electroweak model. In addition, the GALLEX and SAGE experiments,
which currently have large statistical uncertainties, differ from the
predictions of the standard solar model by 2σ and 3σ, respectively.
Title: Women in astronomy: a sampler of issues and ideas.
Authors: Barlow, N.; Cordova, F. A.; Bahcall, J.; Price, J.; Eastwood,
K.; Bahcall, N.; Clayton, G.; Lutz, J.; Bell Burnell, J.; Hunter, D.;
Rubin, V.; McFadden, L.; Faber, S.; Knapp, G.; Alvarez Del Castillo,
E. M.; Trimble, V.
Bibcode: 1992Mercu..21...27B
Altcode:
No abstract at ADS
Title: An Issue of Neglect for Astronomy?
Authors: Harrison, Shirley W.; Zirin, Harold; Bahcall, John N.
Bibcode: 1992PhT....45b.128H
Altcode:
No abstract at ADS
Title: Solar neutrinos and the Mikheyev-Smirnov-Wolfenstein theory
Authors: Bethe, Hans A.; Bahcall, John N.
Bibcode: 1991PhRvD..44.2962B
Altcode:
The observation of solar neutrinos by Kamiokande shows that
the solar-neutrino problem cannot be solved by changing
the solar model. In combination with the observations
with a chlorine detector, it makes the nonadiabatic form
of the Mikheyev-Smirnov-Wolfenstein theory most likely, and
determines Δm2sin2θ=1.0×10-8
eV2. Probably all neutrinos go through the resonance
in the Sun, those from 8B nonadiabatically, all others
adiabatically. The latter emerge from the Sun in the higher-mass
eigenstate ν2 and have a probability sin2θ
to be detected as νe. The gallium experiments,
when done with sufficient accuracy, will be able to determine
Δm2=m2(νμ)-m2(νe)
within fairly close limits. If the day-night effect can be
measured, it will further constrain these limits. The small value
of Δm2sin2θ explains why the oscillation
from νe to νμ has not been observed in the
laboratory. From existing experiments, the temperature at the center of
the Sun can be determined to be within about 6% of that derived from
the standard solar model; future neutrino experiments may determine
it to within 1%.
Title: Ultraviolet HST Spectra of Three Small Redshift Quasars
Authors: Bahcall, J. N.; Jannuzi, B.; Schneider, D. P.; Hartig, G.
Bibcode: 1991BAAS...23.1344B
Altcode:
No abstract at ADS
Title: Shapes of solar-neutrino spectra: Unconventional tests of
the standard electroweak model
Authors: Bahcall, John N.
Bibcode: 1991PhRvD..44.1644B
Altcode:
The shapes of the neutrino energy spectra produced by β decays
or by nuclear reactions in the solar interior are compared to the
corresponding spectral shapes that are produced in a terrestrial
laboratory. The most important effects of the Sun, caused by thermal
motion of the neutrino-emitting nuclei and by gravitational redshifts,
are shown to be small. Any currently measurable difference between the
observed shape of a solar-neutrino energy spectrum and the spectrum
shape for a terrestrial neutrino source must be due to a departure
from the standard electroweak model.
Title: The HST Snapshot Survey: A Progress Report on New Gravitational
Lenses and Lensing Statistics
Authors: Maoz, D.; Bahcall, J. N.; Schneider, D. P.; Doxsey, R.;
Bahcall, N. A.; Lahav, O.; Yanny, B.
Bibcode: 1991BAAS...23.1352M
Altcode:
No abstract at ADS
Title: The Ultraviolet Absorption Spectrum of 3C 273
Authors: Bahcall, J. N.; Jannuzi, B. T.; Schneider, D. P.; Hartig,
G. F.; Bohlin, R.; Junkkarinen, V.
Bibcode: 1991ApJ...377L...5B
Altcode:
We identify six Lyα absorption systems with equivalent widths greater
than 0.2 A in the ultraviolet spectrum of the nearby quasar 3C 273,
more than expected on the basis of extrapolations of the observed
number of Lyα clouds seen at large redshifts. Two Lyα lines appear
to be produced by gas in the Virgo Cluster or by the halos of galaxies
associated with the Virgo Cluster. We also detect all the interstellar
absorption lines that are expected on the basis of abundance, atomic
physics, and ionization considerations.
Title: Quasar Absorption Line Survey: Cycle 2 Observations
Observations of OJ287 and PG1718+481
Authors: Bahcall, John
Bibcode: 1991hst..prop.4817B
Altcode:
The Quasar Absorption Line Survey of bright sources is an efficient
observing program designed to provide a homogeneous data base of
absorption features. The data will reveal absorption regions in
galaxies, in clusters of galaxies, in voids, in large-scale structures,
in Lyman ALPHA clouds, and wi provide information about damped Lyman
ALPHA and Lyman-limit systems. The survey will determine, with high SNR,
the profiles of > 200 emission lines. Using the estimated numbers
of observed absorption lines, including archi val data, the program was
designed to determine the cosmic evolution of absorption systems. High
resolution spectra of a sample of quasars will be obtained with the FOS;
the spectra will have a rest frame equivalent width detection limit
for unresolved absorption lines of 0.3 A. The survey data base will
address fundamental questions, for example: What is the strength and
origin of the UV background radiation\? How do gaseous galactic disks
and halos evolve with redshift\? What processes govern the ionization
of absorbing gas\? THIS SUBMISSION CONTAINS THE CYCLE 2 OBSERVATIONS
OF OJ287 and PG1718+481.
Title: Quasar Absorption Line - for HOPR#0083
Authors: Bahcall, John
Bibcode: 1991hst..prop.4799B
Altcode:
The Quasar Absorption Line Survey of bright sources is an efficient
observing program designed to provide a homogeneous data base of
absorption features. The data will reveal absorption regions in
galaxies, in clusters of galaxies, in voids, in large-scale structures,
in Lyman ALPHA clouds, and will provide information about damped Lyman
ALPHA and Lyman-limit systems. The survey will determine, with high SNR,
the profiles of > 200 emission lines. Using the estimated numbers
of observed absorption lines, including archi val data, the program was
designed to determine the cosmic evolution of absorption systems. High
resolution spectra of a sample of quasars will be obtained with the FOS;
the spectra will have a rest frame equivalent width detection limit for
unresolved absorption lines of 0.3 A. The survey data base will address
fundamental questions, for example: What is the strength and origin of
the UV background radiation\? How do gaseous galactic disks and halos
evolve with redshift\? What processes govern the ionization of absorbing
gas\? How has gaseous structure in the universe evolved on scales of 1
Mpc to 100 Mpc\? Do absorbing systems show evidence of the large-scale
structure seen in the distribution of galaxies and clusters\?
Title: Do Rich Clusters of Galaxies Produce Quasar Absorption Lines :
Cycle 2
Authors: Bahcall, John
Bibcode: 1991hst..prop.4117B
Altcode:
Five quasars [NAB 0024+22, PKS 0003+15, UM 381, UM 324, and AO
1058+11] that lie behind rich clusters of galaxies will be studied
spectroscopically with the FOS to see if the clusters produce
ultraviolet absorption lines. All of the quasar spectra will be used
also to help determine the statistics of quasar absorption lines,
the main goal of the GTO proposal "Evolution of Lyman-alpha and C IV
Absorption Systems" (J. Bahcall, PI). ST observations are required in
order to observe the ultraviolet absorption lines that may be produced
by the nearby rich clusters of galaxies.
Title: The Stellar Density Distributions in the Centers of Galactic
Globular Clusters: Cycle 2 Augmentation
Authors: Bahcall, John
Bibcode: 1991hst..prop.3565B
Altcode:
Short exposures will be made of all galactic globular clusters with
distance moduli less than 15.5 mag and galactic latitude above or below
15 degrees. A search will be made for cusps in the stellar density
distributions and the colors will be measured for the brightest stars
in the cores of the clusters. ST observations are required in order to
reach the innermost regions of the clusters with sufficient resolution
to separate individual stars.
Title: Do Galaxies Produce Quasar Absorption Lines? : Cycle 2
Authors: Bahcall, John
Bibcode: 1991hst..prop.4118B
Altcode:
SPECTRA WILL BE OBTAINED WITH THE FOS FOR A NUMBER OF QUASARS THAT
HAVE A SMALL ANGULAR SEPARATION ON THE SKY FROM GALAXIES OR GALAXY
VOIDS, INCLUDING MARK 205, 3C 232, PKS 2020-370, THE GRAVITATIONALLY
LENSED QUASAR, 2237+0305, 4 OBJECTS BEHIND THE BOOTES GALAXY VOID, US
1329 (BEHIND THE BAHCALL-SONEIRA GALAXY VOID), AND 5C 03.44 (BEHIND M
31). THE SPECTRA WILL BE USED TO TEST THE HYPOTHESIS THAT SOME METALLIC
QUASAR ABSORPTION SYSTEMS ARE CAUSED BY VERY LARGE GALAXY HALOS OR
DISKS. WF/PC IMAGES WILL ALSO BE OBTAINED OF THE LENSING GALAXY,
2237+0305, IN ORDER TO LOCATE ACCURATELY THE QUASAR POSITION AND
MEASURE THE SURFACE BRIGHTNESS OF THE INNER REGION OF THE GALAXY. ST
OBSERVATIONS ARE REQUIRED BECAUSE, FOR THE SMALL REDSHIFTS AT WHICH
GALAXIES WITH LARGE ANGULAR SIZE ARE FOUND, THE RESONANT ATOMIC LINES
ARE IN THE ULTRAVIOLET.
Title: Imaging and Spectroscopy of a Complete Sample of Bright Nearby
Quasars: II. Spectroscopy: Cycle 2 Baseline
Authors: Bahcall, John
Bibcode: 1991hst..prop.3222B
Altcode:
FOS spectra will be obtained for seven optically bright PG quasars
[3C 273, PG 0953+415, PG 1116+215, PKS 1302-102, PG 1700+518, GQ Com,
and 3C 249.1] with Mb </= -25.0 mag and z </= 0.35, as well as V
</= 15.7 mag. The spectra will be analyzed for both absorption and
emission features. ST observations are required because the spectral
features of greatest interest in these small redshift objects are in
the far ultraviolet, inaccessible from the ground.
Title: Evolution of Lyman-Alpha and CIV Absorpton Systems: Cycle 2
Authors: Bahcall, John
Bibcode: 1991hst..prop.4112B
Altcode:
The evolution of Lyman-alpha and CIV absorption line systems in quasar
spectra will be investigated using 21 optically bright quasars with
a wide range of redshifts; the wavelength at which the Lyman cutoff
appears will also be determined. All of the prominent emission and
absorption lines will be measured. ST observations are required because
the spectral features of interest are in the far ultraviolet and are
inaccessible from the ground.
Title: Quasar Absorption Line Survey: Cycle 2 Observations
Authors: Bahcall, John
Bibcode: 1991hst..prop.3791B
Altcode:
The Quasar Absorption Line Survey of bright sources is an efficient
observing program designed to provide a homogeneous data base of
absorption features. The data will reveal absorption regions in
galaxies, in clusters of galaxies, in voids, in large-scale structures,
in Lyman ALPHA clouds, and wi provide information about damped Lyman
ALPHA and Lyman-limit systems. The survey will determine, with high SNR,
the profiles of > 200 emission lines. Using the estimated numbers
of observed absorption lines, including archi val data, the program was
designed to determine the cosmic evolution of absorption systems. High
resolution spectra of a sample of quasars will be obtained with the FOS;
the spectra will have a rest frame equivalent width detection limit for
unresolved absorption lines of 0.3 A. The survey data base will address
fundamental questions, for example: What is the strength and origin of
the UV background radiation\? How do gaseous galactic disks and halos
evolve with redshift\? What processes govern the ionization of absorbing
gas\? How has gaseous structure in the universe evolved on scales of 1
Mpc to 100 Mpc\? Do absorbing systems show evidence of the large-scale
structure seen in the distribution of galaxies and clusters\?
Title: Imaging and Spectroscopy of a Complete Sample of Bright Nearby
Quasars: II. Spectroscopy: Cycle 2
Authors: Bahcall, John
Bibcode: 1991hst..prop.4115B
Altcode:
FOS spectra will be obtained for seven optically bright PG quasars
[3C 273, PG 0953+415, PG 1116+215, PKS 1302-102, PG 1700+518, GQ Com,
and 3C 249.1] with Mb </= -25.0 mag and z </= 0.35, as well as V
</= 15.7 mag. The spectra will be analyzed for both absorption and
emission features. ST observations are required because the spectral
features of greatest interest in these small redshift objects are in
the far ultraviolet, inaccessible from the ground.
Title: Do Galaxies Produce Quasar Absorption Lines: Cycle 2
Augmentaion
Authors: Bahcall, John
Bibcode: 1991hst..prop.3566B
Altcode:
SPECTRA WILL BE OBTAINED WITH THE FOS FOR A NUMBER OF QUASARS THAT
HAVE A SMALL ANGULAR SEPARATION ON THE SKY FROM GALAXIES OR GALAXY
VOIDS, INCLUDING MARK 205, 3C 232, PKS 2020-370, THE GRAVITATIONALLY
LENSED QUASAR, 2237+0305, 4 OBJECTS BEHIND THE BOOTES GALAXY VOID, US
1329 (BEHIND THE BAHCALL-SONEIRA GALAXY VOID), AND 5C 03.44 (BEHIND M
31). THE SPECTRA WILL BE USED TO TEST THE HYPOTHESIS THAT SOME METALLIC
QUASAR ABSORPTION SYSTEMS ARE CAUSED BY VERY LARGE GALAXY HALOS OR
DISKS. WF/PC IMAGES WILL ALSO BE OBTAINED OF THE LENSING GALAXY,
2237+0305, IN ORDER TO LOCATE ACCURATELY THE QUASAR POSITION AND
MEASURE THE SURFACE BRIGHTNESS OF THE INNER REGION OF THE GALAXY. ST
OBSERVATIONS ARE REQUIRED BECAUSE, FOR THE SMALL REDSHIFTS AT WHICH
GALAXIES WITH LARGE ANGULAR SIZE ARE FOUND, THE RESONANT ATOMIC LINES
ARE IN THE ULTRAVIOLET.
Title: Quasar Absorption Line Survey: Cycle 2 Observations
Observations of 3C249-1
Authors: Bahcall, John
Bibcode: 1991hst..prop.4939B
Altcode:
THIS SUBMISSION is a change to P3791 to replace an object that
it is not possible to acquirer with the Binary Search procedure
with another object from our program. The object which has been
removed is IR0450-2958. We are replacing it with 3C249-1 The Quasar
Absorption Line Survey of bright sources is an efficient observing
program designed to provide a homogeneous data base of absorption
features. The data will reveal absorption regions in galaxies, in
clusters of galaxies, in voids, in large-scale structures, in Lyman
ALPHA clouds, and wi provide information about damped Lyman ALPHA
and Lyman-limit systems. The survey will determine, with high SNR,
the profiles of > 200 emission lines. Using the estimated numbers
of observed absorption lines, including archi val data, the program was
designed to determine the cosmic evolution of absorption systems. High
resolution spectra of a sample of quasars will be obtained with the
FOS; the spectra will have a rest frame equivalent width detection
limit for unresolved absorption lines of 0.3 A.
Title: The Ultraviolet Absorption Spectrum of 3c 273
Authors: Bahcall, J. N.; Jannuzi, B. T.; Schneider, D. P.; Hartig,
G. F.; Bohlin, R.; Junkkarinen, V.
Bibcode: 1991BAAS...23R1270B
Altcode:
No abstract at ADS
Title: U.S. Astronomy's Next Decade of Discovery
Authors: Bahcall, John N.
Bibcode: 1991S&T....81..584B
Altcode:
No abstract at ADS
Title: The 1990s: The decade of discovery
Authors: Bahcall, John N.
Bibcode: 1991PhT....44d..24B
Altcode:
Recent achievements and development trends in astronomy and astrophysics
are discussed. Ground- and space-equipment initiatives, recommended by
the Astronomy and Astrophysics Survey Committee, are presented. Large
programs including the Space Infrared Telescope Facility, the
Infrared-Optimized 8-m Telescope, the Millimeter Array, Southern 8-m
Telescope and other small and moderate programs are described. It
is noted that theoretical research in such areas as plasma physics,
atomic physics, nuclear physics, radiative transfer, properties of
matter, which support analysis and interpretation of observation data
should be developed. Establishment of national electronic archives,
development of fast networks for linking most astronomical computers,
and fundamental scientific research in lunar astronomy are also
recommended. Some aspects of international collaboration are noted.
Title: Comments on an historic event
Authors: Bahcall, John N.
Bibcode: 1991NuPhS..19...94B
Altcode:
Theoretical aspects of the solar neutrino problem are reviewed.
Title: Solar-Cycle Modulation of Event Rates in the Chlorine Solar
Neutrino Experiment
Authors: Bahcall, John N.; Press, William H.
Bibcode: 1991ApJ...370..730B
Altcode:
The time dependence of the event rates in the Homestake chlorine
solar neutrino experiment are reexamined using new Ar-37 production
data covering the period from late 1986 to mid-1989. The data span
almost two complete solar cycles. A careful statistical analysis using
nonparametric rank-order statistics is used to calculate quantitative
significance levels that do not depend on experimental errors. The
results show that the Ar-37 production rate in the experiment is
anticorrelated with solar activity for approximately 1977-1989. The
shape of the Ar-37 production rate is different from the inverted
sunspot activity curve. The Ar-37 production rate is better descrbed by
a skewed sawtooth function than by the sunspot number. The best-fitting
sawtooth function with sunspot period has a slow rise and a rapid
decline. The Ar-37 maximum occurs about 12.5 yr after the solar sunspot
minimum, while minimum Ar-37 production is more nearly simultaneous
with the sunspot maximum.
Title: The Decade of Discovery
Authors: Bahcall, J. N.
Bibcode: 1991BAAS...23Q.904B
Altcode:
No abstract at ADS
Title: Prioritizing Scientific Initiatives
Authors: Bahcall, John N.
Bibcode: 1991Sci...251.1412B
Altcode:
No abstract at ADS
Title: The Non-Proprietary Snapshot Survey - a Search for
Gravitationally-Lensed Quasars Using the Hst/ Hubble Space Telescope
Planetary Camera
Authors: Maoz, D.; Bahcall, J. N.; Doxsey, R.; Schneider, D. P.;
Bahcall, N. A.; Lahav, O.; Yanny, B.
Bibcode: 1991fyho.conf..200M
Altcode:
No abstract at ADS
Title: K Giants and the amount of Local Dark Matter
Authors: Bahcall, J.; Flynn, C.; Gould, A.
Bibcode: 1991dodg.conf..105B
Altcode:
No abstract at ADS
Title: Working papers. Astronomy and astrophysics panel reports.
Authors: Bahcall, John N.; Beichman, Charles A.; Canizares, Claude;
Cronin, James; Heeschen, David; Houck, James; Hunten, Donald; McKee,
Christopher F.; Noyes, Robert; Ostriker, Jeremiah P.
Bibcode: 1991wpaa.book.....B
Altcode:
This volume contains the working papers of the panels appointed by
the Astronomy and Astrophysics Survey Committee. These papers were
advisory to the survey committee and represent the opinions of the
members of each panel in the context of their individual charges. The
committee's full survey report is contained in a separately published
document, The decade of discovery in astronomy and astrophysics
(see 003.025). Contents: 1. Radio astronomy. 2. Infrared
astronomy. 3. Optical/IR from ground. 4. UV-optical from
space. 5. Interferometry. 6. High energy from space. 7. Particle
astrophysics. 8. Theory and laboratory astrophysics. 9. Solar
astronomy. 10. Planetary astronomy. 11. Computing and data
processing. 12. Policy opportunities. 13. Benefits to the nation from
astronomy and astrophysics. 14. Status of the profession. 15. Science
opportunities.
Title: IUE/HST Observations of 3C273k
Authors: Bahcall, John
Bibcode: 1991iue..prop.4104B
Altcode:
No abstract at ADS
Title: FOS Observations of the Absorption Spectrum of 3C273
Authors: Bahcall, J. N.; Jannuzi, B. T.; Schneider, D. P.; Hartig,
G. F.; Bohlin, R.; Junkkarinen, V.
Bibcode: 1991fyho.conf...46B
Altcode:
No abstract at ADS
Title: Solar neutrinos: new physics?
Authors: Bahcall, J. N.
Bibcode: 1991NYASA.647...11B
Altcode: 1991tsra.symp...11B
The author concentrates in this report on two theoretical arguments
that suggest - independent of particular solar or particle physics
models - that solar neutrino experiments reveal new physics beyond
the standard electroweak model.
Title: The HST Non-Proprietary SnapShot Survey
Authors: Maoz, D.; Bahcall, J. N.; Doxsey, R.; Schneider, D. P.;
Bahcall, N. A.; Gunn, J. E.; Lahav, O.; Romani, R. W.; Yanny, B.
Bibcode: 1991BAAS...23..832M
Altcode:
No abstract at ADS
Title: New Measurement of Missing Matter in the Galactic Disk
Authors: Gould, A.; Bahcall, J. N.; Flynn, C.
Bibcode: 1991BAAS...23..831G
Altcode:
No abstract at ADS
Title: Non-Proprietary ("snapshot") Survey i Round 2
Authors: Bahcall, John
Bibcode: 1990hst..prop.4027B
Altcode:
Whenever the automatic scheduler produces a substantial gap between
observations, the Wide Field/Planetary Camera will be used to
image a nearby object selected from a list of several hundred low
redshift quasars, normal galaxies, peculiar galaxies, and standard
survey fields. HST observations will reveal details of the immediate
environment of quasars, the nuclei of normal galaxies, the morphology of
peculiar galaxies, and the star density in selected fields. The purpose
of this program is to increase the efficiency of the HST and to provide
scientific data that can be used by many different astronomers. The
images acquired in this program will be non-proprietary and will be made
available to qualified astronomers via the HST archival system. With
the approval of the Director of STScI, the images can also be used
for public relations purposes by appropriate NASA anad STScI personnel.
Title: Gravitational Lens Candidate 1208+101: Photometry
Authors: Bahcall, John
Bibcode: 1990hst..prop.3981B
Altcode:
Planetary Camera images of the high-redshift quasar 1208+101 will
be obtained with several broad band filters. These observations will
determine whether the colors of the three unresolved sources located
within a region 0.6" are the same; if so, then the objects are likely
to be gravitationally lensed images of the quasar. Only HST can provide
sufficient spatial resolution to provide accurate photometry on the
individual images.
Title: Quasar Absorption Line - for HOPR#0037
Authors: Bahcall, John
Bibcode: 1990hst..prop.4044B
Altcode:
The establishment of a homogeneous data base of quasar absorption
lines using the diagnostic survey proposed here will form the basis
for an attack on fundamental cosmological and astrophysical problems:
What are the physical, dynamical and evolutionary properties of the
intergalactic medium? What is the strength, shape and origin of the UV
background radiation? What limits can be set upon the primordial He/H
and D/H ratios? What has been the chemical and dynamical evolution of
gaseous galactic disks and halos? What physical processes govern the
ionization of this gas? What physical processes govern the acceleration
of thermal and relativistic plasma in radio quiet and radio loud
quasars? How has gaseous structure in the universe evolved on scales of
1 Mpc to 100 Mpc? The discrimatory power of the survey and the efficient
use of HST were the primary criteria used in constructing the survey,
which takes account of all relevant GTO observations. Exposure times are
based upon IUE archival data. Ground-based observations of all program
objects will be made to monitor variability and to complement the HST
observations. The survey contains a primary list of 103 quasars with
0.3 < Z_em < 2.0, 18 additional bright quasars to be observed
with the FOS to provide candidates for future HRS follow up, and
a supplementary list of 49 fainter quasars for a damped Ly-alpha
survey. A plausible extrapolation of ground-based data suggests that
the primary survey will detect 275 Ly-alpha and 60 CIV systems.
Title: Imaging and Spectroscopy of a Complete Sample of Bright Nearby
Quasars: II. Spectroscopy: Cycle 1 Observations
Authors: Bahcall, John
Bibcode: 1990hst..prop.3220B
Altcode:
FOS spectra will be obtained for seven optically bright PG quasars
[3C 273, PG 0953+415, PG 1116+215, PKS 1302-102, PG 1700+518, GQ Com,
and 3C 249.1] with Mb </= -25.0 mag and z </= 0.35, as well as V
</= 15.7 mag. The spectra will be analyzed for both absorption and
emission features. ST observations are required because the spectral
features of greatest interest in these small redshift objects are in
the far ultraviolet, inaccessible from the ground.
Title: Gravitational Lens Candidate 1208+101: Spectroscopy
Authors: Bahcall, John
Bibcode: 1990hst..prop.3992B
Altcode:
We will obtain low resolution FOS spectra of the high-redshift quasar
1208+101 and the brightest of two candidate gravitational lens images,
located about .5 arcsec from the primary image. The 0.3 arcsec circular
aperture will be used to spatially resolve the images, to test the
gravitational lens hypothesis. Only HST can provide sufficient spatial
resolution to permit sufficiently accurate spectrophotometry of the
individual images.
Title: Non-Proprietary ("snapshot") Survey Repeat Exposures of 3156
3157 3158 3159
Authors: Bahcall, John
Bibcode: 1990hst..prop.4017B
Altcode:
Whenever the automatic scheduler produces a substantial gap between
observations, the Wide Field/Planetary Camera will be used to
image a nearby object selected from a list of several hundred low
redshift quasars, normal galaxies, peculiar galaxies, and standard
survey fields. HST observations will reveal details of the immediate
environment of quasars, the nuclei of normal galaxies, the morphology of
peculiar galaxies, and the star density in selected fields. The purpose
of this program is to increase the efficiency of the HST and to provide
scientific data that can be used by many different astronomers. The
images acquired in this program will be non-proprietary and will be made
available to qualified astronomers via the HST archival system. With
the approval of the Director of STScI, the images can also be used
for public relations purposes by appropriate NASA anad STScI personnel.
Title: Quasar Absorption Line Survey: Cycle 1 Observations-Fos
Authors: Bahcall, John
Bibcode: 1990hst..prop.2424B
Altcode:
The establishment of a homogeneous data base of quasar absorption
lines using the diagnostic survey proposed here will form the basis
for an attack on fundamental cosmological and astrophysical problems:
What are the physical, dynamical and evolutionary properties of the
intergalactic medium? What is the strength, shape and origin of the UV
background radiation? What limits can be set upon the primordial He/H
and D/H ratios? What has been the chemical and dynamical evolution of
gaseous galactic disks and halos? What physical processes govern the
ionization of this gas? What physical processes govern the acceleration
of thermal and relativistic plasma in radio quiet and radio loud
quasars? How has gaseous structure in the universe evolved on scales of
1 Mpc to 100 Mpc? The discrimatory power of the survey and the efficient
use of HST were the primary criteria used in constructing the survey,
which takes account of all relevant GTO observations. Exposure times are
based upon IUE archival data. Ground-based observations of all program
objects will be made to monitor variability and to complement the HST
observations. The survey contains a primary list of 103 quasars with
0.3 < Z_em < 2.0, 18 additional bright quasars to be observed
with the FOS to provide candidates for future HRS follow up, and
a supplementary list of 49 fainter quasars for a damped Ly-alpha
survey. A plausible extrapolation of ground-based data suggests that
the primary survey will detect 275 Ly-alpha and 60 CIV systems.
Title: Evolution of Lyman-Alpha and CIV Absorpton Systems: Cycle
1 Observations
Authors: Bahcall, John
Bibcode: 1990hst..prop.3221B
Altcode:
The evolution of Lyman-alpha and CIV absorption line systems in quasar
spectra will be investigated using 21 optically bright quasars with
a wide range of redshifts; the wavelength at which the Lyman cutoff
appears will also be determined. All of the prominent emission and
absorption lines will be measured. ST observations are required because
the spectral features of interest are in the far ultraviolet and are
inaccessible from the ground.
Title: Quasar Absorption Line - for HOPR#0025
Authors: Bahcall, John
Bibcode: 1990hst..prop.4000B
Altcode:
The establishment of a homogeneous data base of quasar absorption
lines using the diagnostic survey proposed here will form the basis
for an attack on fundamental cosmological and astrophysical problems:
What are the physical, dynamical and evolutionary properties of the
intergalactic medium? What is the strength, shape and origin of the UV
background radiation? What limits can be set upon the primordial He/H
and D/H ratios? What has been the chemical and dynamical evolution of
gaseous galactic disks and halos? What physical processes govern the
ionization of this gas? What physical processes govern the acceleration
of thermal and relativistic plasma in radio quiet and radio loud
quasars? How has gaseous structure in the universe evolved on scales of
1 Mpc to 100 Mpc? The discrimatory power of the survey and the efficient
use of HST were the primary criteria used in constructing the survey,
which takes account of all relevant GTO observations. Exposure times are
based upon IUE archival data. Ground-based observations of all program
objects will be made to monitor variability and to complement the HST
observations. The survey contains a primary list of 103 quasars with
0.3 < Z_em < 2.0, 18 additional bright quasars to be observed
with the FOS to provide candidates for future HRS follow up, and
a supplementary list of 49 fainter quasars for a damped Ly-alpha
survey. A plausible extrapolation of ground-based data suggests that
the primary survey will detect 275 Ly-alpha and 60 CIV systems.
Title: Non-Proprietary ("snapshot") Survey II Round 2
Authors: Bahcall, John
Bibcode: 1990hst..prop.4028B
Altcode:
Whenever the automatic scheduler produces a substantial gap between
observations, the Wide Field/Planetary Camera will be used to
image a nearby object selected from a list of several hundred low
redshift quasars, normal galaxies, peculiar galaxies, and standard
survey fields. HST observations will reveal details of the immediate
environment of quasars, the nuclei of normal galaxies, the morphology of
peculiar galaxies, and the star density in selected fields. The purpose
of this program is to increase the efficiency of the HST and to provide
scientific data that can be used by many different astronomers. The
images acquired in this program will be non-proprietary and will be made
available to qualified astronomers via the HST archival system. With
the approval of the Director of STScI, the images can also be used
for public relations purposes by appropriate NASA anad STScI personnel.
Title: The Stellar Density Distributions in the Centers of Galactic
Globular Clusters: Cycle 1 Observations
Authors: Bahcall, John
Bibcode: 1990hst..prop.3227B
Altcode:
Short exposures will be made of all galactic globular clusters with
distance moduli less than 15.5 mag and galactic latitude above or below
15 degrees. A search will be made for cusps in the stellar density
distributions and the colors will be measured for the brightest stars
in the cores of the clusters. ST observations are required in order to
reach the innermost regions of the clusters with sufficient resolution
to separate individual stars.
Title: Quasar Absorption Line Survey: Cycle 1 FOS Part II
Authors: Bahcall, John
Bibcode: 1990hst..prop.3418B
Altcode:
The establishment of a homogeneous data base of quasar absorption
lines using the diagnostic survey proposed here will form the basis
for an attack on fundamental cosmological and astrophysical problems:
What are the physical, dynamical and evolutionary properties of the
intergalactic medium? What is the strength, shape and origin of the UV
background radiation? What limits can be set upon the primordial He/H
and D/H ratios? What has been the chemical and dynamical evolution of
gaseous galactic disks and halos? What physical processes govern the
ionization of this gas? What physical processes govern the acceleration
of thermal and relativistic plasma in radio quiet and radio loud
quasars? How has gaseous structure in the universe evolved on scales of
1 Mpc to 100 Mpc? The discrimatory power of the survey and the efficient
use of HST were the primary criteria used in constructing the survey,
which takes account of all relevant GTO observations. Exposure times are
based upon IUE archival data. Ground-based observations of all program
objects will be made to monitor variability and to complement the HST
observations. The survey contains a primary list of 103 quasars with
0.3 < Z_em < 2.0, 18 additional bright quasars to be observed
with the FOS to provide candidates for future HRS follow up, and
a supplementary list of 49 fainter quasars for a damped Ly-alpha
survey. A plausible extrapolation of ground-based data suggests that
the primary survey will detect 275 Ly-alpha and 60 CIV systems.
Title: Solution of the solar-neutrino problem
Authors: Bahcall, John N.; Bethe, H. A.
Bibcode: 1990PhRvL..65.2233B
Altcode:
Comparison of the results from the Kamiokande neutrino-electron
scattering experiment with those from the chlorine experiment and with
solar models shows that the explanation of the solar-neutrino problem
probably requires physics beyond the standard electroweak model with
zero neutrino masses. The experimental results, including the shape
of the electron-recoil energy spectrum measured by Kamiokande,
are in excellent agreement with a nonadiabatic solution of the
Mikheyev-Smirnov-Wulfenstein effect, yielding a neutrino mass difference
of Δm2=1×10-8 sin-2ΘV
eV2.
Title: Book-Review - Neutrino Astrophysics
Authors: Bahcall, J. N.; Haubold, H. J.
Bibcode: 1990AN....311R.421B
Altcode:
No abstract at ADS
Title: Neutrino Astrophysics
Authors: Bahcall, John N.; Wasserman, Ira
Bibcode: 1990AmJPh..58..895B
Altcode:
No abstract at ADS
Title: Element Diffusion in Stellar Interiors
Authors: Bahcall, John N.; Loeb, Abraham
Bibcode: 1990ApJ...360..267B
Altcode:
Simple equations are derived that describe element diffusion in
radiative stellar interiors and that may be incorporated in standard
stellar evolution codes. For the sun, diffusion is expected to increase
the predicted event rates in the Cl-37 solar neutrino experiment
and in electron-neutrino scattering experiments by 5 - 10 percent;
the expected increase in the predictions for Ga-71 solar neutrino
experiments is between 1 and 3 percent.
Title: Kinematic Modeling of the Galaxy. II. Two Samples of High
Proper-Motion Stars
Authors: Casertano, Stefano; Ratnatunga, Kavan U.; Bahcall, John N.
Bibcode: 1990ApJ...357..435C
Altcode:
The paper analyzes two independent surveys, due to Fouts and Sandage and
to Carney and Latham, of high proper motion stars with photoelectric
photometry and line-of-sight velocity information. A purely kinematic
study of both samples indicates that a two-component classical (disk +
spheroid) model of the Galaxy is inadequate to represent the kinematics
of stars in the solar neighborhood. A component with intermediate
kinematic properties (old disk) is required. An asymmetric drift of
50 + or - 15 km/s and principal velocity dispersions of (66, 37, 38)
+ or - 10 km/s are determined, in good agreement with the results of
the metallicity-based analysis of Sandage and Fouts and of Carney and
collaborators. The density of this component is poorly constrained,
and is 10 percent + or - 5 percent of the local disk density for the
same color range; the scale height is less than 1 kpc.
Title: Das Rätsel der fehlenden Sonnenneutrinos.
Authors: Bahcall, J. N.
Bibcode: 1990SpWis...8...76B
Altcode:
No abstract at ADS
Title: The solar-neutrino problem
Authors: Bahcall, John N.
Bibcode: 1990SciAm.262e..54B
Altcode: 1990SciAm.262...54B
Consideration is given to the discrepancies between the theory of
solar neutrino emission and experimentally determined values for the
solar neutrino flux. The results of the Homestake Gold Mine and the
Kamiokande II experiments and the process of neutrino production in the
standard solar model are reviewed. Possible reasons for the discrepancy
between theory and observations are examined, including possible errors
in the standard solar model, experimental error, and a lull in solar
activity. Experiments concerning solar activity are discussed, including
the Sudbury Neutrino Observatory and gallium neutrino detectors such
as the Soviet-American Gallium Experiment and the Gallex program.
Title: The solar-neutrino problem.
Authors: Bahcall, J. N.
Bibcode: 1990SciAm.262e..26B
Altcode: 1990SciAm.262...26B
Far fewer neutrinos from the sun are detected than current physics
predicts. But a grand unification theory that ties together all natural
forces permits neutrinos to change so they are not readily detected
on the earth. New detectors are being designed to spot these "mutant"
neutrinos - and confirm the theory.
Title: Line versus continuum solar neutrinos
Authors: Bahcall, John N.
Bibcode: 1990PhRvD..41.2964B
Altcode:
The rate of neutrino line emission is calculated for nuclei that
are usually assumed to produce only continuum neutrino emission. A
convenient formula is derived that gives for solar interior conditions
the ratio of the rates of neutrino line emission to continuum neutrino
emission. The only significant line emission from the solar interior
is expected from the pep and 7electron capture reactions.
Title: Book reviews
Authors: Bahcall, J. N.; Rosner, R.
Bibcode: 1990SoPh..127..209B
Altcode:
No abstract at ADS
Title: Book-Review - Neutrinos
Authors: Klapdor, H. V.; Bahcall, J. N.
Bibcode: 1990SoPh..127..209K
Altcode:
No abstract at ADS
Title: What the Longest Exposures from the Hubble Space Telescope
Will Reveal
Authors: Bahcall, John N.; Guhathakurta, Puragra; Schneider, Donald P.
Bibcode: 1990Sci...248..178B
Altcode:
Detailed simulations are presented of the longest exposures on
representative fields that will be obtained with the Hubble Space
Telescope, as well as predictions for the numbers and types of objects
that will be recorded with exposures of different durations. The Hubble
Space Telescope will reveal the shapes, sizes, and content of faint,
distant galaxies and could discover a new population of Galactic stars.
Title: Neutrinos from the sun - an astronomical puzzle
Authors: Bahcall, John N.
Bibcode: 1990Mercu..19...53B
Altcode:
The current situation concerning neutrinos from the sun is
summarized. The discussion presents a definition of neutrinos,
an introduction to the science of neutrino astronomy, and the
implications of these findings. It is noted that neutrinos from the
sun and from supernovae provide cosmic particle beams for probing
the weak interactions of particles with energies and on time scales
that cannot be achieved with traditional laboratory experiments. The
solar neutrino unit, or SNU, is defined and the model that provides a
combined description of electrical and weak interaction phenomena is
detailed. The solar neutrino problem is explained and the importance
of neutrino experiments and the theory of stellar evolution is
emphasized. Nuclear energy generation and neutrino fluxes, the Cl-37
experiment, the Kamiokande II experiment, and gallium detectors and
their contribution to understanding the solar neutrino problem are
discussed.
Title: Where are the solar neutrinos?
Authors: Bahcall, J. N.
Bibcode: 1990Ast....18c..40B
Altcode:
No abstract at ADS
Title: Mixing and the Solar Neutrino Problem
Authors: Sienkiewicz, R.; Bahcall, J. N.; Paczynski, B.
Bibcode: 1990ApJ...349..641S
Altcode:
Evolutionary sequences for the sun were calculated assuming continuous
or episodic mixing of matter in the solar interior. The ad hoc mixing
affects solar neutrino emission because it increases the interior H-1
and He-3 content and reduces the temperature at the solar center. For
a typical postulated massive mixing 'event', the flux of the basic pp
neutrinos is strongly reduced for about 10 million yr following the
mixing, and the B-8 neutrino is greatly decreased for more than 10 to
the 8th yr. The flux of hep neutrinos is significantly increased for
about 100,000 yr. The neutrino fluxes calculated from the standard
(unmixed) solar model obtained here with an independent numerical
code agree with the neutrino fluxes of Bahcall and Ulrich (1988)
to an accuracy of a few percent or better.
Title: The solar neutrino mystery.
Authors: Bahcall, J. N.
Bibcode: 1990AsNow...4...15B
Altcode: 1990AstNw...4...15B
When the first attempts were made to test our ideas and understanding
of how the Sun shines, scientists were unexpectedly confronted with
the case of the missing neutrinos. This mystery has stimulated and
confounded scientists since 1968, but may soon be solved. Critical
experiments will soon be performed and a clear understanding of the
neutrino problem will hopefully follow.
Title: Book-Review - Neutrino Astrophysics
Authors: Bahcall, J. N.
Bibcode: 1990AstQ....7..189B
Altcode:
No abstract at ADS
Title: The Standard Solar Model
Authors: Bahcall, John N.; Cribier, M.
Bibcode: 1990ASSL..159...21B
Altcode: 1990IAUCo.121...21B; 1990insu.conf...21B
No abstract at ADS
Title: Book-Review - Neutrino Astrophysics
Authors: Bahcall, J. N.
Bibcode: 1989Sci...246.1648B
Altcode:
No abstract at ADS
Title: Neutrino Astrophysics
Authors: Bahcall, John N.
Bibcode: 1989neas.book.....B
Altcode: 1989QB464.2.B34....
List of tables; List of figures; Preface; 1. Overview; 2. Stellar
structure and evolution; 3. Nuclear fusion reactions; 4. The
standard solar model; 5. Nonstandard solar models; 6. The neutrinos;
7. Theoretical uncertainties; 8. Neutrino cross sections; 9. Beyond the
standard model of electroweak interactions; 10. The 37CI experiment;
11. The 71Ga experiments; 12. Geochemical and radiochemical detectors:
Mo, Tl, Li, Br, I; 13. Neutrino-electron scattering experiments;
14. Direct counting experiments; 15. Stellar collapse; 16. Synopsis
and future directions; Appendix; References; Index.
Title: Matter-enhanced neutrino oscillations in the standard solar
model
Authors: Bahcall, J. N.; Haxton, W. C.
Bibcode: 1989PhRvD..40..931B
Altcode:
The effects of matter-enhanced neutrino oscillations on solar-neutrino
experiments can be calculated accurately only if uncertainties in
the standard solar model are treated properly. As the oscillation
probability depends on the neutrino energy, while modifications in the
parameters of the standard solar model produce correlated changes in
the various solar-neutrino sources, Monte Carlo calculations appear
to offer the only means for addressing this problem. We consider the
effects of matter-enhanced neutrino oscillations for 1000 standard solar
models that were constructed by varying the solar input parameters
according to their estimated probability distributions. From these
Monte Carlo calculations [carried out for a neutrino parameter
grid of 104 cases corresponding to 3×108
separate Mikheyev-Smirnov-Wolfenstein (MSW) calculations] we derive
95%-C.L. limits on the neutrino mass difference δm2
and mixing angle sin22θ for possible outcomes for the
37Cl, 71Ga, and Kamioka II experiments and the
assumption of two-flavor oscillations. We find that 71Ga
counting rates as large as 128 solar-neutrino units (SNU) or as
small as 4 SNU are not ruled out by present 95%-C.L. results from
the 37Cl and Kamioka II experiments, given possible solar
and nuclear cross-section uncertainties. Considering all three of
the experiments, 37Cl (existing results), Kamioka II
(existing results), and 71Ga (hypothesized results), we
find the allowed neutrino parameters form two distinct ``islands''
in the δm2-sin22θ plane for 71Ga
results between 20 and 100 SNU, even with our restrictive assumption of
oscillations between only two flavors. Thus additional experiments may
be required to distinguish between solutions that are each consistent
with the results from the 37Cl, 71Ga, and Kamioka
II experiments. We explore the implications of future Kamioka II results
of improved accuracy. To permit analyses of new experiments that focus
on individual fluxes, we also present separate predictions of the MSW
effect for 7Be and 3+p (hep) neutrinos.
Title: Book-Review - Neutrino Astrophysics
Authors: Bahcall, J. N.; Cherry, M. L.
Bibcode: 1989Natur.340..520B
Altcode:
No abstract at ADS
Title: How does the Sun shine?
Authors: Bahcall, John
Bibcode: 1989Natur.340..265B
Altcode:
No abstract at ADS
Title: Sharing astronomical costs
Authors: Bahcall, John N.
Bibcode: 1989Natur.339..574B
Altcode:
No abstract at ADS
Title: The Magnitude of 3He Diffusion in the Sun
Authors: Loeb, A.; Bahcall, J. N.; Milgrom, M.
Bibcode: 1989ApJ...341.1108L
Altcode:
The diffusion of He-3(2+) has been determined in the four-component
solar plasma. It is found that the fractional diffusive changes in
the solar lifetime are bounded by (-2, +5) percent of the standard
solar model values for the He-3 abundance. These changes are shown
to be negligible in the solar core due to the large rate of the
destruction of diffused ions by the (He-3)-(He-3) and (He-3)-(He-4)
reactions occurring there.
Title: Kinematic Modeling of the Galaxy. I. The Yale Bright Star
Catalogue
Authors: Ratnatunga, Kavan U.; Bahcall, John N.; Casertano, Stefano
Bibcode: 1989ApJ...339..106R
Altcode:
A code has been developed to investigate the kinematic properties
of stellar populations of the Galaxy by modeling the distributions
of proper motion and line-of-sight velocity. The coordinate frames of
reference are discussed in detail and the general matrix transformations
valid beyond the solar neighborhood are given. As a first application,
the kinematic properties of the magnitude-selected sample of 3993
stars in the Bright Star Catalogue with V less than 6.0 and (B-V)
greater than 0 are selected. The observed kinematic distributions
are compared with a conventional model that has an exponential disk
with scale heights, components of velocity dispersion ellipsoid, and
asymmetric drift taken from the literature and defined as functions
of spectral type. The comparisons suggest that a significant fraction
of the Bright Star Catalogue belongs to a relatively young population
that is not properly represented in the model.
Title: Solar Neutrinos: Waiting for Kamiokande II
Authors: Bahcall, J. N.
Bibcode: 1989bbag.conf..399B
Altcode:
No abstract at ADS
Title: Supernova 1987A.
Authors: Arnett, W. David; Bahcall, John N.; Kirshner, Robert P.;
Woosley, Stanford E.
Bibcode: 1989ARA&A..27..629A
Altcode:
The circumstances of SN 1987A are nearly ideal for studying supernovae
and we have a relatively complete observational record. The Large
Magellanic Cloud is fortuitously well placed in the sky, circumpolar
for recently constructed southern observatories and near the ecliptic
pole. These practical advantages, a rich and varied set of observations
can be used to test a well-developed, but hitherto poorly calibrated,
theory for supernova explosions. This review cannot explore every
aspect of SN 1987A. The authors have tried to emphasize the main event:
the test of stellar evolution represented by the observations.
Title: De Vaucouleurs's Galaxy.
Authors: Bahcall, John N.
Bibcode: 1989woga.conf..188B
Altcode:
Gérard de Vaucouleurs proposed the standard geometrical descriptions
of both the disk and spheroid populations of spiral galaxies, and
applied this description in a pioneering model of the Galaxy. This
talk describes the results of computer modeling of the Galaxy using
the de Vaucouleurs distributions for the disk and spheroid.
Title: A Survey of G and K Giants at the South Galactic Pole
Authors: Flynn, C.; Bahcall, J.; Freeman, K. C.
Bibcode: 1989gfpg.conf..105F
Altcode: 1989LDP....12..105F
No abstract at ADS
Title: Solar flares and neutrino detectors
Authors: Bahcall, John N.
Bibcode: 1988PhRvL..61.2650B
Altcode:
Solar flares have been suggested as the cause of occasional high
counting rates in the 37Cl solar-neutrino experiment. The
sensitivity of neutrino detectors to flares is evaluated. Several
neutrino detectors will show large signals when prominent flares are
observed electromagnetically, if flares are detected in the chlorine
experiment.
Title: What will the 98Mo solar-neutrino experiment
measure\?
Authors: Bahcall, John N.
Bibcode: 1988PhRvD..38.2006B
Altcode:
It is shown that the geochemical measurement of the solar-neutrino flux
using 98Mo should yield the same value for the 8B
neutrino flux as is determined by contemporary observations using the
37Cl and Kamiokande II detectors. The 98Mo and
contemporary fluxes should be equal to an accuracy of better than 1%,
provided standard ideas regarding time scales in stellar evolution
are correct.
Title: Solar neutrinos: a field in transition
Authors: Bahcall, John N.; Davis, Raymond, Jr.; Wolfenstein, Lincoln
Bibcode: 1988Natur.334..487B
Altcode:
Solar-neutrino experiments provide a unique opportunity for studying
weak interactions in a realm where new physics may be revealed. At
the same time the neutrinos carry important information about the
physical processes occurring in the otherwise inaccessible core
of a main-sequence star. A variety of experiments, electronic and
radiochemical, must be carried out to determine what new physics and
astronomy are being uncovered with these underground detectors.
Title: Neutral-current reactions of solar and supernova neutrinos
on deuterium
Authors: Bahcall, J. N.; Kubodera, K.; Nozawa, S.
Bibcode: 1988PhRvD..38.1030B
Altcode:
We calculate the cross sections for the neutral-current disintegration
of deuterium by neutrinos and antineutrinos: ν+d-->ν'+n+p
and ν¯+d-->ν¯'+n+p. We put special emphasis on estimates
of the theoretical uncertainties of these cross sections. For
8B and hep solar neutrinos, the averaged cross sections are
<σ(8B)>=4.1(1+/-0.1)×10-43 cm2
and <σ(hep)>=1.15(1+/-0.1)×10-42 cm2,
respectively, where hep denotes 3He+p. The cross-section
uncertainty is negligible, +/-1/2%, for the ratio of neutral-current
to charged-current events. Independent of neutrino oscillations,
the cross sections correspond to 4.5(1+/-0.38)×103
solar-neutrino events per year in the proposed one-kiloton Sudbury
Neutrino Observatory if the standard solar model is correct. For
a galactic supernova, the total number of neutral-current events
expected in the Sudbury detector is about 103 (distance/8
kpc)-2; most of the signal is expected to arise from μ
and τ neutrinos and antineutrinos. If either μ or τ neutrinos have
a mass greater than 2×102 eV, then this mass should be
measurable using the neutrino signal from a galactic supernova.
Title: Supernovae leave their mark
Authors: Bahcall, John N.
Bibcode: 1988Natur.333..301B
Altcode:
No abstract at ADS
Title: Solar models, neutrino experiments, and helioseismology
Authors: Bahcall, John N.; Ulrich, Roger K.
Bibcode: 1988RvMP...60..297B
Altcode:
The event rates and their recognized uncertainties are calculated for
eleven solar neutrino experiments using accurate solar models. The
same solar models are used to evaluate the frequency spectrum of the
p and g oscillation modes of the sun and to compare with existing
observations. A numerical table of the characteristics of the standard
solar model is presented. Improved values have been calculated for all
of the neutrino absorption cross sections evaluating the uncertainties
for each neutrino source and detector as well as the best estimates. The
neutrino capture rate calculated from the standard solar model for
the 37Cl experiment is 7.9(1+/-0.33) SNU, which spans the
total theoretical range; the rate observed by Davis and his associates
is (2.0+/-0.3) SNU. The ratio of the observed to the predicted
flux at Earth of neutrinos from 8B decay lies in the range
0<=[ϕ(8B)observedϕ(8B)predicted]<=0.5.
The recent results from the Kamiokande II electron scattering experiment
confirm this conclusion. This discrepancy between calculation
and observation is the solar neutrino problem. Measurements of the
energy spectrum of solar neutrinos can discriminate between suggested
solutions of the solar neutrino problem. Nonstandard solar models,
many examples of which are also calculated in this paper, preserve the
shape of the energy spectrum from individual neutrino sources, whereas
most proposed weak-interaction explanations imply altered neutrino
energy spectra. Detailed energy spectra of individual neutrino sources
are presented as well as a composite solar neutrino spectrum. hep
neutrinos from the 3He+p reaction, probe a different region
of the solar interior than do 8B neutrinos. Measurements
of the very rare but highest-energy hep neutrinos are possible
in proposed experiments using electron scattering, 2H,
and 40Ar detectors. The standard solar model predicts
p-mode oscillation frequencies that agree to within about 0.5% with
the measured frequencies and reproduce well the overall dispersion
relation of the modes. However, there are several small but significant
discrepancies between the measured and observed frequencies. The
complementarity of helioseismology and solar neutrino experiments
is demonstrated by constructing a solar model with a drastically
altered nuclear energy generation that eliminates entirely the
important high-energy 8B and 7Be neutrinos,
but which affects by less than 0.01% the calculated p-mode oscillation
frequencies.
Title: Book-Review - the Galaxy and the Solar System
Authors: Smoluchowski, R.; Bahcall, J. N.; Matthews, M. S.; Hilditch,
R.
Bibcode: 1988Obs...108...23S
Altcode:
No abstract at ADS
Title: The mass of the electron neutrino: Monte Carlo studies of SN
1987A observations
Authors: Spergel, David N.; Bahcall, John N.
Bibcode: 1988PhLB..200..366S
Altcode:
Monte Carlo simulations of a wide class of possible neutrino emission
models are used to assign statistical significance to the limits set
on the mass of the electron neutrino by observations of SN 1987A. Using
the combined Kamiokande II and IMB data sets, we reject neutrino masses
greater than 16 eV at the 5% significance level.
Title: Simulations of HST observations of globular clusters.
Authors: Bahcall, John N.; Schneider, Donald P.
Bibcode: 1988IAUS..126..455B
Altcode:
Simulations of Hubble Space Telescope observations to study galactic
globular clusters are examined. Studies of the cores of nearby
globular clusters to determine the stellar density distributions and
luminosity functions in the innermost regions of the clusters are
presented. Pictures of M 13 are included to demonstrate the usefulness
of these studies. Stellar population studies of a relatively unobscured
globular cluster to detect white dwarfs and the faint red end of the
cluster luminosity function are discussed and illustrated with pictures
of NGC 6397.
Title: Phenomenological analysis of neutrino emission from SN 1987A.
Authors: Bahcall, J. N.; Spergel, D. N.; Press, W. H.
Bibcode: 1988slmc.proc..172B
Altcode:
The allowed range of the nu(e) emission temperature, rise time, cooling
time, flux, and total energy of the neutrino emission from SN 1987A
are determined from Monte Carlo and maximum likelihood analyses. The
acceptable ranges are found to be 4.2 + 1.2, - 0.8 MeV for temperature,
4.5 + 1.7, - 2.0 sec for cooling time, and 6.1 + 3.5, - 3.6 x 10 to
the 52nd N(all) erg for total emitted energy, where N(all) is the
ratio of energy emitted in all neutrino forms to that emitted in the
form of nu(e). It is suggested that masses of nu(e) that exceed 16 eV
at the 5 percent significance level can be rejected.
Title: Neutrinos and sunspots
Authors: Bahcall, J. N.
Bibcode: 1987Natur.330..318B
Altcode:
No abstract at ADS
Title: Is Solar Neutrino Capture Rate Correlated with Sunspot Number?
Authors: Bahcall, J. N.; Field, G. B.; Press, W. H.
Bibcode: 1987ApJ...320L..69B
Altcode:
The statistical significance of the apparent correlation between
sunspots and the observed neutrino rate is quantified. It is shown that
the correlation depends almost entirely upon four low neutrino capture
rates near the beginning of 1980. A calculation based on standard
electroweak theory and neutrino production processes demonstrates that
a correlation, if real, would be extremely puzzling on energetic grounds
alone. It is concluded that measurements with the Cl-37 detector during
the next sunspot cycle will be needed to show that there is a physical
correlation, since the existing data are not statistically significant
at a definitive level.
Title: An Analysis of the Yale Bright Star Catalog
Authors: Bahcall, John N.; Casertano, Stefano; Ratnatunga, Kavan U.
Bibcode: 1987ApJ...320..515B
Altcode:
The authors analyze the direction, color, and apparent-magnitude
distributions of a complete sample of 3993 stars with mv≤
6.0 mag and B-V ≥ 0.0 from the Yale Bright Star Catalog (BSC). Many
of the sample stars are intrinsically bright disk giants. The total
number and overall distributions of the BSC stars (excluding O and B
stars) are well described by the standard Galaxy model with two major
density components. The spatial distribution of O and B stars shows a
density enhancement due to the Gould Belt in a 15° region inclined
about 20°±3° to the Galactic plane. The total number of O and B
stars in the Galaxy is estimated to be ≡107.
Title: A Simple Model for Neutrino Cooling of the Large Magellanic
Cloud Supernova
Authors: Spergel, D. N.; Piran, T.; Loeb, A.; Goodman, J.; Bahcall,
J. N.
Bibcode: 1987Sci...237.1471S
Altcode:
A simplified analytic model of a cooling hot neutron star, motivated
by detailed computer calculations, describes well the neutrinos
detected from the recent supernova in the Large Magellanic Cloud. The
observations do not require explanations that invoke exotic physics
or complicated astrophysics. The parameters in this simple model
are not severely constrained: 6.1-3.6+3.5
× 1052 ergs emitted in electron antineutrinos, a peak
temperature of 4.2-0.8+1.2 megaelectron volts,
a radius of 27-15+17 kilometers, and a cooling
time of 4.5-2.0+1.7 seconds.
Title: Book-Review - the Galaxy and the Solar System
Authors: Smoluchowski, R.; Bahcall, J. N.; Matthews, M. S.
Bibcode: 1987Sci...237...89S
Altcode:
No abstract at ADS
Title: Neutrino temperatures and fluxes from the LMC supernova
Authors: Bahcall, J. N.; Piran, T.; Press, W. H.; Spergel, D. N.
Bibcode: 1987Natur.327..682B
Altcode: 1987Nat...327..682B
The observation1,2 of neutrinos from the LMC supernova
makes possible direct tests of the theory of supernova explosions
and of properties of weakly interacting particles. Here we describe a
combined analysis of the angular and energy distributions of the events
observed in the Kamiokande and the 1MB detectors which determines the
effective temperatures and fluxes of neutrinos and anti-neutrinos*
produced by the explosion. Our main result is that a simple model is
consistent with the available data and in reasonable agreement with
conventional models of supernova explosions. The parameters of the model
are: a single temperature, T, of 4.1+1.0 -0.4
MeV, a flux of electron anti-neutrinos of (O.5-0.35
+0.2)×1010cm-2 [total energy
in \vmacre = (3.0+1.7 -1.4 ×
1052 erg)], and a poorly determined flux of 'scattered' (see
below) neutrinos = (0.2-5)× 1010 cm-2. Several
statistical tests were used to determine the acceptable range of
these parameters. We have also set limits on possible high-temperature
fluxes of neutrinos or anti-neutrinos that might result from matter
oscillations3,4
Title: Dust Distribution in Spiral Galaxies
Authors: Kylafis, Nikolaos D.; Bahcall, John N.
Bibcode: 1987ApJ...317..637K
Altcode:
A method for determining the dust distribution in edge-on, late Hubble
type, spiral galaxies from their surface photometry is described. The
method assumes that both the stars and the dust are distributed
isothermally in the direction perpendicular to the galactic plane with
scale heights z(s) and z(d) respectively, and exponentially in the
radial direction with corresponding scale lengths h(s) and h(d). By
comparing the observed surface photometry and the model calculations
in which the radiative transfer is treated properly, z(s), z(d), h(s),
and h(d) can be determined, as well as the optical depth along the line
of sight and the central brightness. As a demonstration, the method is
applied to NGC 891. The extension of the method to early-type spiral
galaxies and to inclination angles less than 90 deg is described.
Title: Book-Review - the Galaxy and the Solar System
Authors: Smoluchowski, R.; Bahcall, J. N.; Matthews, M. S.
Bibcode: 1987S&T....73Q.624S
Altcode:
No abstract at ADS
Title: Book-Review - the Galaxy and the Solar System
Authors: Smoluchowski, R.; Bahcall, J. N.; Matthews, M. S.; Bailey,
M. E.
Bibcode: 1987Sci...236..619S
Altcode:
No abstract at ADS
Title: Mikheyev-Smirnov-Wolfenstein effect in electron-neutrino
scattering experiments
Authors: Bahcall, J. N.; Gelb, J. M.; Rosen, S. P.
Bibcode: 1987PhRvD..35.2976B
Altcode:
We calculate the influence of resonant neutrino scattering
[the Mikheyev-Smirnov-Wolfenstein (MSW) effect] in the Sun and
in the Earth on measurable quantities in solar-neutrino-electron
scattering experiments. The MSW effect reduces the expected rate for
8electron scattering by a factor that ranges from ~0.8
to ~0.2 if resonant scattering is the correct explanation for the
discrepancy between observation and calculation in the 37Cl
experiment. The Earth can produce a significant diurnal effect for
certain values of the neutrino mixing angle and mass difference.
Title: Upper limit on the mass of the electron neutrino
Authors: Bahcall, J. N.; Glashow, S. L.
Bibcode: 1987Natur.326..476B
Altcode:
The historic detection by the Kamiokande-II collaboration1
and the IMB collaboration2 of neutrinos from the Large
Magellanic Cloud (LMC) supernova provides the first opportunity to
determine the mass, mvc, of the electron
neutrino from astronomical observations. Here we show that
mvc, is less than 11 eV, provided only that
propagation effects have not conspired to sharpen, by more than a
factor of two the narrow pulse-width of neutrinos, observed by the
Kamiokande-II collaboration from the LMC supernova. This result improves
on the laboratory limit on mvc and confirms the
view that electron neutrinos do not constitute the major component of
the matter density of the Universe.
Title: Neutrino-electron scattering and solar neutrino experiments
Authors: Bahcall, John N.
Bibcode: 1987RvMP...59..505B
Altcode:
Neutrino-electron scattering experiments can elucidate the flavor
content, spectrum shape, intensity, time dependence, and angular
distribution of solar neutrinos. The author presents detailed
calculations for all of the important solar neutrino sources of the
predicted energy and angular dependence of the recoil electrons, as
well as the total cross sections. In addition, the author discusses
how neutrino-electron experiments can help distinguish between various
proposed solutions of the solar neutrino problem.
Title: Neutrinos from the recent LMC supernova
Authors: Bahcall, J. N.; Dar, A.; Piran, T.
Bibcode: 1987Natur.326..135B
Altcode: 1987Nat...326..135B
No abstract at ADS
Title: Supernova 1987A in the Large Magellanic Cloud
Authors: West, R. M.; Madsen, C.; Bahcall, J.; Dar, A.; Piran, T.;
Murdin, P.; Beresford, T.
Bibcode: 1987IAUC.4329....2W
Altcode: 1987IAUC.4329....1W; 1987IAUC.4329....0W
R. M. West, European Southern Observatory, informs us that a color
exposure (Agfachrome 1000 RS, Hasselblad 6 x 6) of the LMC was made by
C. Madsen at La Silla during Feb. 23.042-23.056 UT. Sanduleak -69 202 is
just seen near the limiting magnitude of about 12. J. Bahcall, A. Dar
and T. Piran, Institute for Advanced Study, Princeton, communicate
the following note, prepared in advance of the report of the neutrino
detection on IAUC 4323: "We have calculated the event rate expected in
terrestrial neutrino detectors from neutrinos produced in the formation
of the neutron star in the LMC supernova. Using neutrino fluxes from a
model stellar collapse calculation of Wilson et al. and cross sections
from Bahcall, we estimate that only about one atom of Ar is produced in
the Davis Cl tank, but that about 50 electron recoils, with energies of
about 10 MeV, are produced in the Kamiokande II water detector. We also
estimate about 3 events each in the scintillators of the University of
Pennsylvania (Homestake Mine) and the Italian- Russian collaboration
(Mont Blanc). The results are sensitive to the effective temperature of
the emitted neutrino spectrum." P. Murdin, Royal Greenwich Observatory,
reports: "It is not clear whether the relative constancy of the light
curve of SN 1987A from Feb. 25 to Mar. 3 represents the maximum in a
typical type II light curve or the 20 day premaximum halt seen in SN
1940B and 1941A. If SN 1987A follows precedent, either it will decline
soon to mag 6, where it will remain in the post-maximum plateau until
early May, or it will brighten in mid-March to a maximum at mag about
2, remaining brighter than mag 6 until early July. Observers should be
aware of this uncertainty when planning observations." Visual magnitude
estimate by T. Beresford, Adelaide, South Australia: Mar. 3.42 UT, 4.3.
Title: Kinematic Model of Our Galaxy
Authors: Ratnatunga, K. U.; Bahcall, J. N.; Casertano, S.
Bibcode: 1987BAAS...19..679R
Altcode:
No abstract at ADS
Title: Dark Matter in the Galactic Disk
Authors: Bahcall, John N.
Bibcode: 1987IAUS..117...17B
Altcode:
Observational data on the distributions of tracer stars, F dwarfs
and K giants were used as input to obtain self-consistent solutions
for the Poisson and Vlasov equations to set bounds on the amount of
missing matter in the solar neighborhood. The numerical computations
were carried out using Galaxy models which feature multiple disk
components and an unseen massive halo. The star data included the
mass components and velocity dispersions. Consideration of various
possible distributions of the unseen matter leads to the conjecture
that half of the disk material in the solar neighborhood has yet to be
observed. Techniques for determining if brown dwarfs are a significant
component of the missing mass are discussed, as are improved models
which would use limited numbers of tracer stars to set further
constraints on the amount and distribution of the missing mass.
Title: Estimating the Masses of Galaxy Groups - Alternatives to the
Virial Theorem
Authors: Heisler, J.; Tremaine, S.; Bahcall, J.
Bibcode: 1987IAUS..117..113H
Altcode:
No abstract at ADS
Title: Some Possible Regularities in Missing Mass
Authors: Bahcall, John N.; Casertano, Stefano
Bibcode: 1987dmu..conf...50B
Altcode:
No abstract at ADS
Title: Dark matter in the universe. Proceedings of the Fourth
Jerusalem Winter School for Theoretical Physics, held at Jerusalem,
Israel, 30 December 1986 - 8 January 1987.
Authors: Bahcall, J.; Piran, T.; Weinberg, S.
Bibcode: 1987dmup.book.....B
Altcode:
No abstract at ADS
Title: Dark Matter Near the Sun
Authors: Bahcall, John N.
Bibcode: 1987dmu..conf....2B
Altcode:
No abstract at ADS
Title: K-Giants and the Total Amount of Matter Near the Sun
Authors: Bahcall, John N.
Bibcode: 1987dmu..conf...13B
Altcode:
No abstract at ADS
Title: K-giants and the total amount of matter near the Sun.
Authors: Bahcall, J. N.
Bibcode: 1987IAUS..117...13B
Altcode:
Reprint of paper 38.155.084.
Title: Dark matter in the universe
Authors: Bahcall, John N.; Piran, T.; Weinberg, S.
Bibcode: 1987dmu..conf.....B
Altcode:
No abstract at ADS
Title: Solutions to the solar neutrino problem?
Authors: Bahcall, J.
Bibcode: 1987PhT....40a..11B
Altcode:
No abstract at ADS
Title: Dark Matter in the Solar Vicinity
Authors: Bahcall, John N.
Bibcode: 1987dmu..conf....1B
Altcode:
No abstract at ADS
Title: Dark matter near the Sun.
Authors: Bahcall, J. N.
Bibcode: 1987IAUS..117....2B
Altcode:
Reprint of paper 43.155.059.
Title: Distribution of Dark Matter in the Spiral Galaxy NGC 3198
Authors: van Albada, T. S.; Bahcall, John N.; Begeman, K.; Sanscisi, R.
Bibcode: 1987dmu..conf...58V
Altcode:
No abstract at ADS
Title: Distribution of dark matter in the spiral galaxy NGC 3198.
Authors: van Albada, T. S.; Bahcall, J. N.; Begeman, K.; Sanscisi, R.
Bibcode: 1987IAUS..117...58V
Altcode:
[Reprint of paper 40.157.046.]
Title: Some possible regularities in missing mass.
Authors: Bahcall, J. N.; Casertano, S.
Bibcode: 1987IAUS..117...50B
Altcode:
Reprint of paper 39.157.203.
Title: Some Regularities in the Missing Mass Problem
Authors: Casertano, S.; Bahcall, J. N.
Bibcode: 1987IAUS..117..136C
Altcode:
The authors discuss available information on the distribution of
luminous and dark matter in eight galaxies.
Title: Dark matter near the Sun
Authors: Bahcall, J. N.
Bibcode: 1987mcu..conf..111B
Altcode:
No abstract at ADS
Title: Dark Matter near the Sun
Authors: Bahcall, J. N.
Bibcode: 1986RSPTA.320..543B
Altcode: 1986RSLPT.320..543B
The amount of dark matter in the disc of the Galaxy at the solar
position is determined by comparing the observed distributions of tracer
stars with the predictions obtained from different assumptions of how
the unseen matter is distributed. The major uncertainties, observational
and theoretical, are estimated. For all the observed samples, typical
models imply that about half of the mass in the solar vicinity must
be in the form of unobserved matter. The volume density of unobserved
material near the Sun is about [Note: Equation omitted. See the image
of page 111 for this equation.]; the corresponding column density
is about [Note: Equation omitted. See the image of page 111 for this
equation.] (1 pc ≈ 30857 × 1012 m). This, so far unseen,
material must be in a disc with an exponential scale height of less
than 0.7 kpc. All the existing observations are consistent with the
unseen disc material being in the form of stars not massive enough
to burn hydrogen. It is suggested that the unseen material that is
required to hold up the rotation curves of galaxies and to satisfy the
virial theorem for clusters of galaxies might also be in the form of
low-mass stars.
Title: Tests of neutrino stability
Authors: Bahcall, J. N.; Petcov, S. V.; Toshev, S.; Valle, J. W. F.
Bibcode: 1986PhLB..181..369B
Altcode:
A possible solution of the solar neutrino problem is that electron
neutrinos decay in transit from the sun. The phenomenological
consequences of this hypothesis for solar neutrino experiments
with detectors of 2H, 40Ar, 71Ga,
98Mo, and electron-neutrino scattering are discussed. The
postulated fast decay can occur in models of majoron type without
violating laboratory, cosmological, or astrophysical constraints. Address after January 1st, 1987: Department de Física Teòrica,
Universitat de Valencia, Burjassot, Valencia, Spain.
Title: Multiple quasars for multiple images
Authors: Bahcall, John N.; Bahcall, Neta A.; Schneider, Donald P.
Bibcode: 1986Natur.323..515B
Altcode: 1986Nat...323..515B
Three quasar pairs that have been identified as the products of
gravitational lenses have no obvious visible lenses1-3. They
are: 1146+111 (redshift z=1.01; pair separation Δθ=157 arc
s)3, 1635+267 (z=1.96; Δθ=4 arc s)1 and
2345+007 (z=2.15; Δθ=7 arc s)2. An even number (two)
of quasar images is observed in each case, although an odd number
of images is produced by gravitational lenses with non-singular
potentials4. The absence of a visible lens creates, in
the lens hypothesis, a severe `missing matter' problem. The missing
lenses range in estimated mass3,5 from >1012
M solar for 1635+267 (where M solar is the mass
of the Sun) to ~1015 M solar for 1146+111. We
investigate here the possibility that these quasar images are pairs
of physically distinct quasars in galaxy associations. We show that,
at the same redshifts as the quasars, only galaxy associations of
exceptional richness would be identifiable in the existing data. Less
prominent groups of galaxies, such as those known to be associated with
nearby quasars6, would not be visible. We calculate the
probability of pairs of quasars appearing in galaxy associations and
find that physical pairs could appear with the observed frequency if,
as expected, quasars are more common relative to galaxy associations
at earlier epochs. We also discuss observations that can distinguish
between the hypothesis of a gravitational lens and that of physical
pairs.
Title: Predictions for a liquid argon solar neutrino detector
Authors: Bahcall, J. N.; Baldo-Ceolin, M.; Cline, D. B.; Rubbia, C.
Bibcode: 1986PhLB..178..324B
Altcode:
A liquid argon time projection chamber can be used to make separate
measurements of electron neutrinos and neutrinos of different
flavors, to determine the incident neutrino spectrum, and to verify
that neutrinos come from the direction of the sun. Resonant neutrino
oscillation has a dramatic effect on the shape of the predicted spectrum
of recoil electrons.
Title: Kinematics and Density of the Galactic Spheroid
Authors: Bahcall, J. N.; Casertano, S.
Bibcode: 1986ApJ...308..347B
Altcode:
The authors reanalyze Eggen's proper-motion and radial velocity
data for a sample of 94 stars with transverse velocities in excess
of 220 km s-1, correcting for observational biases and
selection effects by a Monte Carlo analysis of simulated catalogs of
proper-motion stars. They obtain a local spheroid number density of n =
(9.5±1.3)×10-5pc-3 for 4 ≤ MV ≤
11 mag. The Eggen catalog yields the following kinematic parameters
for the spheroid: an asymmetric drift of 154 km s-1
(corresponding to a rotation velocity ≡66 km s-1), and
velocity dispersions in the r, θ, and z directions of 140, 100, and
76 km s-1, respectively. All three of the commonly applied
definitions of the spheroid (pressure supported, low metallicity,
and geometric distribution) yield consistent results for the density
of Population II stars in the vicinity of the Sun.
Title: Solar neutrinos from the decay of 8B
Authors: Bahcall, John N.; Holstein, Barry R.
Bibcode: 1986PhRvC..33.2121B
Altcode:
The spectrum of neutrinos produced by the beta decay of 8B
in the sun is computed including forbidden corrections to the weak
interactions. The total cross section for absorption by 37Cl
of 8B neutrinos is (1.06+/-0.1)×10-42
cm2. The uncertainty is determined by calculating the
cross section using different measured spectra for the alpha particles
that result from the decay of 8B to 8Be and by
varying the transition matrix elements consistent with the branching
ratios measured using delayed protons emitted in the beta decay of
37Ca.
Title: Wide Binaries in the Direction of Andromeda
Authors: Bahcall, John N.; Jones, Burton F.; Ratnatunga, Kavan U.
Bibcode: 1986ApJS...60..939B
Altcode:
A statistically well-defined sample of candidate binary stars with
separations that are expected to be mostly in the range 0.01-0.1
pc is presented. The 36 candidate pairs are all brighter than
apparent visual magnitude 12; about half of the projected pairs are
expected to be physically associated. After the candidates are studied
spectroscopically and photometrically to establish which pairs are real
binaries and to measure their physical characteristics, the sample
can be used to help determine the dependence of number density on
semimajor axis for wide binaries, a function that is of considerable
theoretical interest.
Title: The galactic environment of the solar system.
Authors: Bahcall, John N.
Bibcode: 1986gss..conf....3B
Altcode: 1986gass.book....3B
The general features of the galactic environment of the solar system
are described. The principal components of the distribution of matter
in the solar vicinity are discussed. Special emphasis is placed upon
the question of determining the total amount of matter in the vicinity
of the Sun.
Title: Solar neutrinos: theory.
Authors: Bahcall, J. N.
Bibcode: 1986wein.conf..705B
Altcode:
No abstract at ADS
Title: Missing matter in the vicinity of the Sun.
Authors: Bahcall, John N.
Bibcode: 1986isos.book..207B
Altcode:
The Poisson and Vlasov equations are solved numerically for realistic
Galaxy models which include multiple disk components, a Population
II spheroid, and an unseen massive halo. The total amount of matter
in the vicinity of the sun is determined by comparing the observed
distributions of tracer stars, samples of F dwarfs, and K giants with
the predictions of the Galaxy models. Results are obtained for a number
of different assumed distributions of the unseen disk mass. For all
the observed samples, typical models imply that about half of the mass
in the solar vicinity must be in the form of unobserved matter. The
volume density of unobserved material near the sun is about 0.1 solar
mass/cu pc; the corresponding column density is about 30 solar mass/sq
pc. This so far unseen material must be in a disk with an exponential
scale height of less than 0.7 kpc.
Title: Solar Neutrinos
Authors: Bahcall, John N.
Bibcode: 1986hmac.book...85B
Altcode:
Contents: 1. Introduction. 2. Stellar evolution. 3. Nuclear
fusion in the Sun. 4. The 37Cl solar neutrino
experiment. 5. Uncertainties in the predictions. 6. Observational
implications. 7. New experiments. 8. Conclusion.
Title: Brown dwarfs: conference summary.
Authors: Bahcall, J. N.
Bibcode: 1986abd..proc..233B
Altcode:
Some of the major observational and theoretical issues in the study of
brown dwarfs are reviewed. It is concluded that all of the unseen local
disk matter could be in the form of brown dwarfs without conflicting
with any available observations.
Title: Star counts and galactic structure.
Authors: Bahcall, John N.
Bibcode: 1986ARA&A..24..577B
Altcode:
Star counts are discussed as an aid in studies of galactic
structure. Iterative computations using a method-of-color-bins to match
numerical models with observational data are described. The star counts
provide bounds for the luminosity function and the color-magnitude
diagram and allow spheroid normalization in a copycat Galaxy model
which posits a galaxy with a Population I disk and a Population
II spheroid. Good agreement has been obtained between star counts
predicted by the model and observed distributions, including color
and magnitude ranges and direction. Modifications being considered
for the model include consideration of the halo, a galactic bulge and
a thick disk. Several galactic structural features which have yet to
be modeled and which may be tractable to the copycat model corrected
with star counts are identified.
Title: An analysis of the Basel star catalog.
Authors: Bahcall, J. N.; Ratnatunga, K. U.; Buser, R.; Fenkart, R. P.;
Spaenhauer, A.
Bibcode: 1985ApJ...299..616B
Altcode:
The standard Bahcall-Soneira (1980) Galaxy model is compared with
the data from the 12 fields in the Basel star catalog that are at
Galactic latitudes above 20 deg and have E(B-V) of less than 0.1
mag. Good agreement is found between the calculated and observed color
distributions, as well as star counts, for all the fields. The globular
cluster feature that is observed in the luminosity function of globular
clusters near M(v) = +1 to +4 mag is also present in the spheroid
field stars. It is possible to assign some of the spheroid stars from
the standard two-component Galaxy model (thin disk plus de Vaucouleurs
spheroid) to a third stellar component (a thick disk with a spheroid
luminosity function) without disturbing the agreement with observations.
Title: Estimating the masses of galaxy groups: alternatives to the
virial theorem.
Authors: Heisler, J.; Tremaine, S.; Bahcall, J. N.
Bibcode: 1985ApJ...298....8H
Altcode:
The authors present three alternatives to the virial
theorem for estimating the masses of groups of
galaxies. The projected mass estimator uses the mean
value of Vi2|Ri|,
where Vi and Riare the radial
velocity and projected separation of galaxy i from the group
center. The other two methods rely on the average and median of
(Vi-Vj)2|Ri-Rj|
over all pairs of galaxies in the group. These three estimators and the
virial theorem estimator are tested using a series of N-body simulations
and Monte Carlo realizations of Michie models. The authors use the mass
estimators to calculate the masses and mass-to-light ratios of nearby
groups catalogued by Huchra and Geller. The results confirm their work,
implying that there is a large amount of dark mass in groups on scales
of ≡700 kpc.
Title: The Solar Neutrino Problem
Authors: Bahcall, J. N.
Bibcode: 1985SoPh..100...53B
Altcode:
The observed capture rate for solar neutrinos in the 37Cl
detector is lower than the predicted capture rate. This discrepancy
between theory and observation is known as the `solar neutrino
problem'. I review the basic elements in this problem: the detector
efficiency, the theory of stellar (solar) evolution, the nuclear physics
of energy generation, and the uncertainties in the predictions. I also
answer the questions of: So What? and What Next?
Title: Estimated number of field stars toward galactic globular
clusters andlocal group galaxies.
Authors: Ratnatunga, K. U.; Bahcall, J. N.
Bibcode: 1985ApJS...59...63R
Altcode:
Field star densities are estimated for 89 fields with /b/ greater than
10 degrees based on the Galaxy model of Bahcall and Soneira (1980,
1984; Bahcall et al. 1985). Calculated tables are presented for 76
of the fields toward Galactic globular clusters, and 16 Local Group
Galaxies in 13 fields. The estimates can be used as an initial guide
for planning both ground-based and Space Telescope observations of
globular clusters at intermediate-to-high Galactic latitudes.
Title: Sampling errors in the determination of the total amount of
mass at the solar position
Authors: Gilden, D. L.; Bahcall, J. N.
Bibcode: 1985ApJ...296..240G
Altcode:
The sampling errors that occur in the determination of the total volume
and column density of mass at the solar position have been evaluated
by analyzing simulated star catalogs as if they were observed sets of
stars. The simulations were achieved by generating ensembles of stellar
orbits that pass through the solar position in a realistic mass model
of the Galaxy. These orbits are sampled in a way that mimics observing
procedures in order to form pseudo-star catalogs. The catalogs are used
to determine the sampling errors in a derivation of the total volume
density of matter near the Sun (the Oort limit). The simulations show
that the overall analysis is unbiased. It is demonstrated that sampling
errors alone cannot account for the missing matter in the disk, as
analyzed most recently by Bahcall.
Title: Gamow-Teller strength function in 71Ge via the
(p,n) reaction at medium energies
Authors: Krofcheck, D.; Sugarbaker, E.; Rapaport, J.; Wang, D.;
Bahcall, J. N.; Byrd, R. C.; Foster, C. C.; Goodman, C. D.; van
Heerden, I. J.; Gaarde, C.; Larsen, J. S.; Horen, D. J.; Taddeucci,
T. N.
Bibcode: 1985PhRvL..55.1051K
Altcode:
The Gamow-Teller strength function in 71Ge has been measured
by use of the 71Ga(p,n) reaction at Ep=120 and 200
MeV. While a significant fraction of the total strength is associated
with excited states located below particle-emission threshold, the first
excited state exhibits little strength. Excited-state contributions to
the total solar-neutrino capture rate for a 71Ga detector are
about 14 solar neutrino units for the neutrino spectrum of the standard
solar model and about 3-4 solar neutrino units for representative
nonstandard solar models.
Title: Distribution of dark matter in the spiral galaxy NGC 3198.
Authors: van Albada, T. S.; Bahcall, J. N.; Begeman, K.; Sancisi, R.
Bibcode: 1985ApJ...295..305V
Altcode:
Two-component mass models, consisting of an exponential disk and a
spherical halo, are constructed to fit a newly determined rotation
curve of NGC 3198 that extends to 11 disk scale lengths. The amount of
dark matter inside the last point of the rotation curve, at 30 kpc,
is at least 4 times larger than the amount of visible matter, with
M/L(B)tot = 18 solar M/L(B). The maximum mass-to-light ratio for the
disk is M/L(B) = 3.6. The available data cannot discriminate between
disk models with low M/L and high M/L, but arguments are presented
which suggest that the true mass-to-light ratio of the disk is close
to the maximum computed value. The core radius of the distribution of
dark matter is found to satisfy R(core) of between 1.7 and 12.5 kpc.
Title: The Sun's motion perpendicular to the galactic plane
Authors: Bahcall, J. N.; Bahcall, S.
Bibcode: 1985Natur.316..706B
Altcode:
The period and amplitude of the Sun's motion perpendicular to the
galactic plane are important parameters in some explanations of the
terrestrial mass extinctions and cratering records1-5. Here
we have calculated the range of periods and vertical excursions that are
consistent with the distributions of tracer stars in the Galaxy and have
also evaluated the probable phase jitter in the solar period. We find
acceptable half-periods for the vertical oscillation that range from 26
to 37 Myr (including the range of periods that have been inferred from
the terrestrial records on mass extinctions and on cratering), maximum
heights above the plane from 49 to 93 pc, and an average phase jitter
per half-period of the order of 6-9%. The largest uncertainty in all
these calculations is caused by the unknown distribution of the unseen
mass that must be postulated to explain the distribution of observed
stars6-7. For all the models we consider, the most recent
passage of the Sun through the galactic plane occurred in the past
3 Myr provided only that the present position of the Sun is between
0 and 20 pc above the plane. We extend the argument of Thaddeus and
Chanan8 to show that the apparent periodicity in the mass
extinction and cratering records cannot be caused by an population of
objects (observed or unobserved) that contributes a major fraction of
the total mass density at the solar vicinity.
Title: Some possible regularities in the missing mass problem.
Authors: Bahcall, J. N.; Casertano, S.
Bibcode: 1985ApJ...293L...7B
Altcode:
In the present consideration of the missing mass problem, equations
are developed which express relatively well determined parameters
characterizing the internal properties of all the mass models invoked in
a sampling of spiral galaxy cases. The numerical values thus obtained
constitute benchmarks, relative to which theories of spiral galaxy
formation can be tested. Simple regularities are noted to be exhibited
by the unseen matter in the spiral galaxy sample. Attention is given to
the possibility that both the visible and invisible matter are baryonic.
Title: Chlorine and gallium solar neutrino experiments
Authors: Bahcall, J. N.; Cleveland, B. T.; Davis, R., Jr.; Rowley,
J. K.
Bibcode: 1985ApJ...292L..79B
Altcode:
The authors reevaluate the expected capture rates and their
uncertainties for the chlorine and gallium solar neutrino experiments
using improved laboratory data and new theoretical calculations. They
also derive a minimum value for the flux of solar neutrinos that
is expected provided only (1) that the sun is currently producing
energy by fusing light nuclei at the rate that it is emitting energy
in the form of photons from its surface and (2) that nothing happens
to solar neutrinos on their way to earth. These results are used -
together with Monte Carlo simulations - to determine how much gallium
is required for a solar neutrino experiment.
Title: Solar neutrino detection: Experimental determination of
Gamow-Teller strengths via the 98Mo and 115In
(p,n) reactions
Authors: Rapaport, J.; Welch, P.; Bahcall, J.; Sugarbaker, E.;
Taddeucci, T. N.; Goodman, C. D.; Foster, C. F.; Horen, D.; Gaarde,
C.; Larsen, J.; Masterson, T.
Bibcode: 1985PhRvL..54.2325R
Altcode:
The empirical distribution of Gamow-Teller strengths in 98Tc
and 115Sn have been obtained via the (p,n) reaction at
Ep=120 MeV and Ep=200 MeV on 98Mo
and 115In targets. This information is used to calculate
the cross section for absorption of solar neutrinos in 98Mo
and 115In, nuclides which are being considered as neutrino
detectors to accomplish solar neutrino spectroscopy.
Title: Maximum mass of objects that constitute unseen disk material
Authors: Bahcall, J. N.; Hut, P.; Tremaine, S.
Bibcode: 1985ApJ...290...15B
Altcode:
It is suggested that the mass of the individual unseen 'disk things'
which furnish unseen mass satisfies an inequality that is based on
the demonstrated existence of a large number of wide binary stars in
the Galaxy whose projected separations are as large as 0.1 pc. Since
these binaries are weakly bound, with orbital velocities of 0.3 km/sec
and periods of the order of 1 million years, they can be disrupted by
passing stars or other pointlike objects. This implies that the mass
of the unseen disk objects, which provide about half the local mass
density, must be less than 2 solar masses.
Title: The Total Amount of Matter in the Solar Vicinity
Authors: Bahcall, J. N.
Bibcode: 1985BAAS...17..581B
Altcode:
No abstract at ADS
Title: An Analysis of the Basel Star Catalog
Authors: Ratnatunga, K. U.; Bahcall, J. N.; Buser, R.; Fenkart, R. P.;
Spaenhauer, A.
Bibcode: 1985BAAS...17Q.559R
Altcode:
No abstract at ADS
Title: On the Density of the Spheroid in the Solar Neighborhood
Authors: Casertano, S.; Bahcall, J. N.
Bibcode: 1985BAAS...17..560C
Altcode:
No abstract at ADS
Title: Comparisons of the Standard Galaxy Model with observations
in two fields
Authors: Bahcall, J. N.; Ratnatunga, K. U.
Bibcode: 1985MNRAS.213P..39B
Altcode:
The Bahcall-Soneira (1984) model for the distribution of stars in
the Galaxy is compared with the observations reported by Gilmore,
Reid, and Hewett (1984) in two directions in the sky, the pole and
the Morton-Tritton (1982) region. It is shown that the Galaxy model
is in good agreement with the observations everywhere it has been
tested with modern data, including the magnitude range, V = 17-18,
and provided that the globular cluster feature is included in the
luminosity function of the field Population II stars.
Title: On the spatial distribution of population II stars in SB and
later type galaxies.
Authors: Bahcall, J. N.; Kylafis, N. D.
Bibcode: 1985ApJ...288..252B
Altcode:
It is shown that surface-brightness measurements must be accurate to
about 0.1 mag at 1 percent of the visual sky brightness in order to
determine the spatial distribution of Population II stars in Sb galaxies
with bulge-to-disk ratios like those in NGC 891 and in galaxies of
later Hubble type. The observations of van der Kruit and Searle (1981)
of the edge-on galaxy NGC 891 are fitted with two different models:
a thin disk and a de Vaucouleurs spheroid, and a thin disk plus a
thicker disk. The observations are well described by both models. The
difficulty of discriminating between various shapes for the light
distribution of Population II stars increases with galaxy inclination.
Title: Space Telescope observations of globular clusters.
Authors: Bahcall, J. N.
Bibcode: 1985IAUS..113..481B
Altcode:
Six proposed Space Telescope programs involving globular clusters are
described. The projects appropriate for galactic clusters are: the
detection of white dwarfs, the study of the faint end of the Population
II luminosity function, the measurement of mass segregation, and the
search for a cusp in the density distribution caused by core collapse
or by a massive black hole. The two programs that involve extragalactic
globular clusters are: the determination of the luminosity function
of clusters around different galaxies and the measurement of tidal
radii of clusters surrounding elliptical galaxies.
Title: The solar neutrino problem: astronomy or physics?
Authors: Bahcall, J. N.
Bibcode: 1985fsgf.book..267B
Altcode: 1986fsgf.book..267B
A review of current theoretical and observational attempts to resolve
the solar neutrino dilemma is presented.
Title: Solar neutrino experiments: Theory
Authors: Bahcall, J. N.
Bibcode: 1985AIPC..126...60B
Altcode: 1985snna.proc...60B
The expected capture rates and their uncertainties are reevaluated
for the chlorine and gallium experiments using improved laboratory
data and new theoretical calculations. I also state a minimum value
for the flux of solar neutrinos that is expected provided only that
the sun is currently burning light nuclei at the rate it is emitting
photons from its surface and that nothing happens to solar neutrinos
on their way to the earth. These results are used-together with Monte
Carlo simulations performed by Bruce Cleveland-to determine how much
gallium is required for a solar neutrino experiment.
Title: K giants and the total amount of matter near the sun
Authors: Bahcall, J. N.
Bibcode: 1984ApJ...287..926B
Altcode:
The Poisson and Boltzmann equations are solved numerically for realistic
Galaxy models which include multiple disk components (between 14 and
28), a Population II spheroid, and an unseen massive halo. As a guide in
constructing the theoretical models, a population of normal-metallicity
(disk) K giants is isolated using existing data and is shown to be
well described by an isothermal distribution function with a velocity
dispersion perpendicular to the plane of 20 km s-1. The
total amount of matter in the vicinity of the Sun is determined by
comparing the observed distributions of K giants with the predictions
of detailed Galaxy models. The volume density of unobserved material
near the Sun is about 0.1 M_sun; pc-3; the corresponding
column density is about 30 M_sun; pc-2.
Title: Dark Matter Near the Sun: Simulated Star Counts and the
Oort Limit
Authors: Gilden, D.; Bahcall, J. N.
Bibcode: 1984NASCP2345..326G
Altcode: 1984lism.rept..326G; 1984IAUCo..81..326G
An ensemble of orbits passing through the solar position have been
generated for a specific mass model of the galaxy. These orbits are
randomly sampled to form simulated density distributions of tracer stars
perpendicular to the galactic disk. The simulated distributions are
analyzed in order to determine the sampling errors in a self-consistent
derivation of the total amount of matter near the Sun (the Oort limit).
Title: Velocity dispersions of disk stars in spiral galaxies.
Authors: Bahcall, J. N.; Casertano, S.
Bibcode: 1984ApJ...284L..35B
Altcode:
For multicomponent spiral disks, the authors derive a relation for
individual stellar components between the total surface density of
mass and the observed luminosity scale height and vertical velocity
dispersion. A criterion is given for the validity of the relation in
the presence of spheroidal mass distributions and an inhomogeneous
disk. Mass models for the Milky Way and NGC 891, 4565, and 5907 are
used to illustrate what velocity dispersions observers might expect
to measure in nearly face-on spiral galaxies.
Title: Detection of binaries with projected separations as large as
0.1 parsec.
Authors: Latham, D. W.; Tonry, J.; Bahcall, J. N.; Soneira, R. M.;
Schechter, P.
Bibcode: 1984ApJ...281L..41L
Altcode:
Repeated, accurate radial velocity measurements have been made of the 19
candidate wide binary stellar pairs of Bahcall and Soneira. There are 16
unambiguous cases of which six pairs are physical binaries. Projected
separations of the binaries are estimated using the observed angular
separations and well-determined spectroscopic parallaxes. The projected
separations vary from about 0.002 pc to 0.08 pc. This validation of
the statistical techniques used in identifying the candidate wide
binaries opens up the possibility of large-scale systematic studies
of the characteristics of wide binaries.
Title: K-Giants and the Total Amount of Matter Near the Sun
Authors: Bahcall, J. N.
Bibcode: 1984BAAS...16..733B
Altcode:
No abstract at ADS
Title: Comparisons of a standard galaxy model with stellar
observations in five fields.
Authors: Bahcall, J. N.; Soneira, R. M.
Bibcode: 1984ApJS...55...67B
Altcode:
Modern data on the distribution of stellar colors and on the number
of stars as a function of apparent magnitude in five directions
in the Galaxy are analyzed. It is found that the standard model is
consistent with all the available data. Detailed comparisons with
the data for five separate fields are presented. The bright end of
the spheroid luminosity function and the blue tip of the spheroid
horizontal branch are analyzed. The allowed range of the disk scale
heights and of fluctuations in the volume density is determined, and
a lower limit is set on the disk scale length. Calculations based on
the thick disk model of Gilmore and Reid (1983) are presented.
Title: Current Status of Solar Neutrino Research
Authors: Bahcall, J.
Bibcode: 1984BAAS...16..521B
Altcode:
No abstract at ADS
Title: Self-consistent determinations of the total amount of matter
near the sun.
Authors: Bahcall, J. N.
Bibcode: 1984ApJ...276..169B
Altcode:
The combined Poisson-Boltzmann equation for the gravitational
potential is solved numerically for detailed Galaxy models whose mass
components have been determined previously by a variety of observational
techniques. The basic assumption made is that the disk is composed of
a finite number of isothermal components. The calculated potential as
a function of height above the plane is used to fit the distribution
of F stars reported by Hill, Hilditch, and Barnes to a distance of 200
pc. The inferred mass and column densities depend upon the model adopted
for the unseen matter. The total mass density at the solar position is
0.185 + or - 0.02 solar mass per cu pc if the distribution of unobserved
matter is proportional to the distribution of observed material,
the Bahcall and Soneira Galaxy model is adopted, and the isothermal
approximation is valid. The corresponding column density is 67 solar
mass per sq pc, and the disk mass-to-light ratio is 2.9. The total mass
and column densities are computed for a number of other assumptions
about the unobserved material and the Galaxy model. The inferred
mass and column densities are not sensitive to small contaminations
or departures from isothermality in the sample of F stars that was
used. The unobservd disk material is at least as large as 50 percent
of the total observed disk material in all of the models considered.
Title: The distribution of stars perpendicular to galactic disk
Authors: Bahcall, J. N.
Bibcode: 1984ApJ...276..156B
Altcode:
The combined Boltzmann and Poisson equations for the isothermal
distribution of stars perpendicular to a galactic disk are solved in the
presence of a spheroidal halo. The solutions depend in a simple way upon
the ratio, epsilon, of effecive halo mass density to disk mass density
in the fundamental plane of the disk. These results suggest a new way of
measuring the ratio of halo to disk mass densities either by observing
the number of stars of a given type as a function of height above
the plane in the Galaxy or by observing the distribution of starlight
perpendicular to the disks of other galaxies. Exact numerical - and
approximate analytic solutions are derived for disks that are composed
of one or several separate stellar components. Non-isothermal solutions
are also discussed. The advantages of using the self-consistent models
described here for the determination of the total amount of matter
near the sun are enumerated.
Title: El Telescopio Espacial.
Authors: Bahcall, J. N.; Spitzer, L., Jr.
Bibcode: 1984RvA....56....9B
Altcode:
No abstract at ADS
Title: Missing Matter in the Vicinity of the Sun
Authors: Bahcall, J. N.
Bibcode: 1984ASSL..110..241B
Altcode: 1984astt.coll..241B; 1984IAUCo..78..241B
The combined Poisson-Boltzmann equation for the gravitational potential
is solved numerically for a detailed Galaxy model. The main result -
obtained by comparing the calculated densities with observations of
F dwarfs and K giants - is that about half of the mass density in the
vicinity of the sun has not yet been observed.
Title: Some constraints N the color-magnitude diagram of giants in
the galactic spheroid.
Authors: Bahcall, J. N.; Soneira, R. M.; Morton, D. C.; Tritton, K. P.
Bibcode: 1983ApJ...272..627B
Altcode:
The color-magnitude diagram of giants in the Galactic spheroid is shown
to be important in determining the number-color histogram of stars
brighter than B = 19 mag. This result is demonstrated by comparing a
standard Galaxy model with observations of 391 stars in a field in
the direction of Aquarius (l = 36.5 deg, b = -51.1 deg). More than
80 percent of the spheroid stars and 40 percent of all stars in this
magnitude range and direction are predicted to be giants. At most,
a few percent of the spheroid stars in the current sample can lie on
the main sequence bluer than the turn-off onto the giant branch near
B - V approximately 0.4. The available observations suggest that the
blue tip of the horizontal branch of the spheroid must be sparsely
populated about a factor of 10 less than would be expected if the
color-magnitude diagram of the spheroid were the same as diagrams for
any of the globular clusters M3, M13, or M92. The total dispersion in
colors (measurement errors and intrinsic dispersion) has a standard
deviation in B - V color that is less than 0.2 mag.
Title: The Total amount of Matter Near the Sun
Authors: Bahcall, J. N.
Bibcode: 1983nssl.conf..271B
Altcode: 1983IAUCo..76..271B; 1983LDP.....4..271B
The combined Poisson-Boltzmann equation for the gravitational potential
is solved numerically for detailed Galaxy models whose mass components
have been determined previously by a variety of observational
techniques. The calculated potential as a function of height above
the plane is used to fit the distribution of F stars reported by Hill,
Hilditch, and Barnes to a distance of 200 pc. The total mass density
at the solar position is 0.185±0.02 M_sun; pc-3 if the
distribution of unobserved matter is proportional to the distribution
of observed material, the Bahcall and Soneira Galaxy model is adopted,
and the isothermal approximation is valid.
Title: Detection of Stars in the Dark Galactic Halo
Authors: Bahcall, J. N.; Soneira, R. M.
Bibcode: 1983nssl.conf..223B
Altcode: 1983LDP.....4..223B; 1983IAUCo..76..223B
The authors show how available star counts to mv = 22
together with a model of the Galaxy can be used to set limits on the
maximum brightness of the stellar constituents of a massive halo. They
find there can be few stars brighter than Mv = +14 in an
r-2 halo component.
Title: Comparison of the Bahcall / Soneira Galaxy Model with
Observations
Authors: Bahcall, J. N.; Soneira, R. M.
Bibcode: 1983nssl.conf..209B
Altcode: 1983LDP.....4..209B; 1983IAUCo..76..209B
Modern data on the distribution of stellar colors and on the number
of stars as a function of apparent magnitude in five directions in
the Galaxy are analyzed. Observational studies by various authors are
analyzed. All of the data are described well by a two-component model
with an exponential disk and a de Vaucouleurs spheroid. The fat-disk
model proposed by Gilmore and Reid does not fit the results of Kron
for SA57 and of Koo and Kron for SA68.
Title: Binary-single star scattering. I - Numerical experiments for
equal masses
Authors: Hut, P.; Bahcall, J. N.
Bibcode: 1983ApJ...268..319H
Altcode:
A first report is presented regarding an extensive project which is
designed to provide a representative coverage of binary-single star
scattering, and at least an exploration of binary-binary scattering. It
is the aim of the project to present cross sections and reaction
rates which are obtained by numerical orbit integration from initial
conditions determined by Monte Carlo techniques. The main difference
between the current project and previous work is related to the large
amount of computer time available. In this connection, it has already
been possible to conduct a million orbit calculations. The results
of these calculations are analyzed in this report. A framework of
binary-single star scattering is described for the most general
case. Data are provided for the case where all stars have equal masses.
Title: The ratio of the unseen halo mass to the luminous disk mass
in NGC 891.
Authors: Bahcall, J. N.
Bibcode: 1983ApJ...267...52B
Altcode:
The present investigation has the objective to provide an estimate of
the range of halo to disk mass ratios which are compatible with the
available observations for NGC 891 and to suggest ways by which future
observations could add to the understanding of the mass distribution in
this galaxy. It is found that the ratio of total halo to disk mass for
NGC 891 varies by more than an order of magnitude for phenomenological
models based on the available observations. The models with halo to
disk mass ratios of order unity have self-gravitating stellar disks
(close to the plane of the disk) out to galactocentric distances of at
least as large as 21 kpc, the apparent truncation radius. A model with
a very massive halo has a disk which is not self-gravitating beyond
R approximately 7 kpc.
Title: Stellar collapses in the Galaxy.
Authors: Bahcall, J. N.; Piran, T.
Bibcode: 1983ApJ...267L..77B
Altcode:
Comparisons are made between the sensitivities of the one existing
chlorine vat neutrino detector and gravity wave detectors for
providing evidence of stellar collapse. The galactic star fraction
within detection range is calculated as a controlling factor for the
detectors. An expected collapse rate of 0.1 per year is projected by
using a model of star distribution in the disk and standard values
for Population I star lifetimes. A maximum detection radius of 1.5 kpc
is obtained, as well as a detection rate of 0.0006/yr, two orders of
magnitude less than the observational upper limit. For stars between
3-10 solar masses, the expected detection rate is 0.01/yr. The existing
solar neutrino detector is concluded not to have registered a stellar
collapse in the last 10 yr. Only 6 pecent of the stars in the galaxy
can be monitored with present gravity wave detectors, and methods for
increasing their effectiveness to 90 percent are indicated.
Title: Galaxies, quasars, and beyond - The Space Telescope
Authors: Bahcall, J. N.
Bibcode: 1983aans.sympR..25B
Altcode:
The overall NASA plans for the Space Telescope are described. A brief
history of the development of the Space Telescope is presented and
the major characteristics of the ST Observatory are summarized. The
astronomical instruments that will be used in the first few years are
described and some of the important scientific projects are outlined.
Title: The galactic spheroid
Authors: Bahcall, J. N.; Soneira, R. M.; Schmidt, M.
Bibcode: 1983ApJ...265..730B
Altcode:
Analytic approximations and numerical simulations are used to derive
the characteristic behavior of star counts in a galactic spheroidal
population, whose visible stars' stellar luminosity function is
obtainable for galactocentric distances between about 4 and 12 kpc
from star count observations above 30 deg galactic latitude. The
total densities of stars and of mass in the spheroid at the solar
position are evaluated using different assumed luminosity functions,
in order to extrapolate the measured values to a wider range of absolute
magnitudes. The upper limits to the frequency of intermediate population
stars are derived for the absolute visual magnitude range of 5-8. If
such stars occur in either a flat disk with a scale height of 3 kpc
or a spheroid with an ellipticity of 0.5, their local surface density
is less than 1.8 times that of the spheroid.
Title: Solar neutrinos.
Authors: Bahcall, J. N.
Bibcode: 1983neap.conf...71B
Altcode:
No abstract at ADS
Title: The distribution of stars in the Galaxy
Authors: Bahcall, J. N.; Soneira, R. M.
Bibcode: 1983ASSL..100..209B
Altcode: 1983kdsm.work..209B
A discussion is presented of the basic ideas underlying the use of
star counts to determine galactic parameters. Previous work using star
counts is reviewed, and possible future observational programs that
will be important in increasing the knowledge of the stellar content
of the galaxy are indicated. The techniques used in star counts are
illustrated by applications to the differential number-magnitude
counts in SA 57, the frequency-color diagrams in SA 57 and SA 68,
the paucity of intermediate population stars in the range M(V) = 5-8,
and the M/L ratio for the unseen matter in the halo.
Title: Galaxies, quasars, and beyond - the Space Telescope.
Authors: Bahcall, J. N.
Bibcode: 1983gqb..book.....B
Altcode:
The overall NASA plans for the Space Telescope are described. A brief
history of the development of the Space Telescope is presented and
the major characteristics of the ST Observatory are summarized. The
astronomical instruments that will be used in the first few years are
described and some of the important scientific projects are outlined.
Title: Asymmetric emission-line regions with out-flowing mass in
QSOs and the z/ab/ at least equal to z/em/ systems
Authors: Goldman, I.; Bahcall, J. N.
Bibcode: 1982A&A...115..242G
Altcode:
A heuristic asymmetrical model for a quasar emission-line region,
with material streaming out, is described. The physical parameters
are essentially the same as those of static models; the geometry
turns out to be the dominant factor in determining the emission line
profiles. Calculations are carried out for a variety of parameterized
flow models and for the Blumenthal and Mathews (1975) theoretical
model of a radiatively driven flow. The emission-line profiles are
insensitive to the details of the acceleration, the filling factor,
and the ionization profile. Absorption is assumed to take place in
stationary matter in the QSO's galaxy or associated group or cluster,
so that z(ab) is identified with the cosmological redshift. Due
to the flow, the emission-lines are shifted with respect to the
absorption-lines; in cases of a flow directed towards the observer
systems with z(ab) at least equal to z(em) result. The distribution
of absorption redshifts is symmetric about z(em).
Title: On the interpretation of rotation curves measured at large
galactocentric distances
Authors: Bahcall, J. N.; Schmidt, M.; Soneira, R. M.
Bibcode: 1982ApJ...258L..23B
Altcode:
It is shown that the inferred slope of the density law for a massive
galactic halo is sensitive to the distribution of mass within the
radius of interest. Illustrative rotation curves are presented that
are flat to + or - 1 km/s in the region from 40 to 60 kpc, but which
have local logarithmic slopes for the halo density law of about 2.7
(and in one case a finite total mass) instead of the conventionally
assumed logarithmic slope of 2.0. The contributions of the disk and
spheroid must be taken into account in the intermediate region of
about 10-30 kpc in which most current observations are being carried
out. These results complicate the interpretation of galaxy rotation
curves at large galactocentric distances.
Title: The Space Telescope
Authors: Bahcall, J. N.; Spitzer, L., Jr.
Bibcode: 1982SciAm.247a..40B
Altcode: 1982SciAm.247...40B
After defining the problems posed for optical telescopy by atmospheric
absorption in the infrared and ultraviolet regions, and a brief history
of attempts to date to circumvent these problems by the deployment of
small telescopes aboard rockets, balloons and satellites, a description
is given of the design features and operational capabilities of the
NASA Space Telescope. This telescope, which is scheduled to be put in
earth orbit by the Space Shuttle in 1985, will have a 2.4 m-diameter
primary mirror capable of concentrating electromagnetic radiation from
all optical parts of the spectrum and carry scientific instruments which
will record ultrahigh resolution astronomical images. The telescope's
scientific instrument section will include a high speed photometer,
a high resolution spectrograph, a faint object spectrograph, a wide
field planetary camera, and a faint object camera
Title: Standard solar models and the uncertainties in predicted
capture rates of solar neutrinos
Authors: Bahcall, John N.; Huebner, Walter F.; Lubow, Stephen H.;
Parker, Peter D.; Ulrich, Roger K.
Bibcode: 1982RvMP...54..767B
Altcode:
The uncertainties that affect the prediction of solar neutrino fluxes
are evaluated with the aid of standard solar models. The uncertainties
are determined from available data for all measured quantities that
are known to affect significantly the neutrino fluxes; these include
nuclear reaction rates, the solar constant, and the primordial surface
composition of the sun. Uncertainties in theoretical quantities
(such as the stellar opacity, the equation of state, and the rate of
the proton-proton reaction) are estimated from the range of values
in published state-of-the-art calculations. The uncertainty in each
neutrino flux that is caused by a specified uncertainty in any of
the parameters is evaluated with the aid of a series of standard
solar models that were constructed for this purpose; the results are
expressed in terms of the logarithmic partial derivative of each flux
with respect to each parameter. The effects on the neutrino fluxes
of changing individual parameters by large amounts can usually be
estimated to satisfactory accuracy by making use of the tabulated
partial derivatives. An overall "effective 3σ level of uncertainty"
is defined using the requirement that the true value should lie within
the estimated range unless someone has made a mistake. Effective 3σ
levels of uncertainty, as well as best estimates, are determined for
the following possible detectors of solar neutrinos: 2H,
7Li, 37Cl, 71Ga, 79Br,
81Br, 97Mo, 98Mo, 115In,
and electron-neutrino scattering. The most important sources of
uncertainty in the predicted capture rates are identified and discussed
for each detector separately. For the 37Cl detector,
the predicted capture rate is 7.6+/-3.3 (effective 3σ errors)
SNU. The measured production rate is (Cleveland, Davis, and Rowley,
1981) 2.1+/-0.3 SNU (1σ error). For a 71Ga detector,
the expected capture rate is 106 (1+0.12-0.08)
SNU (also effective 3σ errors). The relatively small uncertainty
quoted for the 71Ga detector is a direct result of the
fact that 71Ga is primarily sensitive to neutrinos from
the basic proton-proton reaction, the rate of which is determined
largely by the observed solar luminosity. The Caltech and Munster
measured values for the cross-section factor for the reaction
3He(α,γ)7Be are inconsistent with each
other. The capture rates quoted above were obtained using the Caltech
value for the cross-section factor. If the Munster value is used
instead, then the predicted capture rate for the 37Cl
experiment is 4.95+/-2.1 SNU (effective 3σ errors) and, for the
71Ga experiment, 96.7 (1+0.12-0.08) SNU
(effective 3σ errors). In order for the best-estimate value to agree
with the observation of Davis (1978) of 2 SNU for the 37Cl
experiment, the cross-section factor S34 (0) would have
to be reduced by about 15σ to less than the Caltech value, i.e. to
7σ less than the Munster value. The characteristics of the standard
solar model, constructed with the best available nuclear parameters,
solar opacity, and equation of state, are presented in detail. The
computational methods by which this and similar models were obtained are
also described briefly. The primordial helium abundance inferred with
the aid of standard solar models is Y=0.25+/-0.01. The complementary
relation between observations of solar neutrinos and of the normal
modes of oscillation of the sun is examined. It is shown that the
splitting of the observed large-n, small-l, p-mode (five minute)
oscillations of the sun primarily originates in the outer ten percent
of the solar mass, while the neutrinos from 8B beta decay
originate primarily in the inner five percent of the solar mass. The
solar luminosity, and the flux of neutrinos from the proton-proton
reaction, come mostly from an intermediate region.
Title: Three-Body Gravitational Scatterings
Authors: Hut, P.; Bahcall, J. N.
Bibcode: 1982BAAS...14..654H
Altcode:
No abstract at ADS
Title: An Account of the Development of the Solar Neutrino Problem
Authors: Bahcall, J. N.; Davis, R., Jr.
Bibcode: 1982ena..conf..243B
Altcode:
No abstract at ADS
Title: The Gallium Solar Neutrino Detector.
Authors: Hampel, W.; Davis, R., Jr.; Cleveland, B. T.; Friedlander,
G.; Katcoff, S.; Remsberg, L. P.; Rowley, J. K.; Weneser, J.; Kirsten,
T.; Heusser, G.; Hübner, M.; Kiko, J.; Pernicka, E.; Schlotz, R.;
Wunderlich, R.; Dostrovsky, I.; Bahcall, J. N.; Lande, K.; Steinberg,
R. I.
Bibcode: 1982AIPC...96...88H
Altcode:
No abstract at ADS
Title: Solar nutrinos
Authors: Bahcall, J. N.
Bibcode: 1981NASCP2191...81B
Altcode: 1981vsc..conf...81B
The topics covered include: an overview of the subject of solar
neutrinos, a brief summary of the theory of stellar evolution, a
description of the main sources of solar neutrinos, a brief summary
of the results of the Brookhaven C1-37 experiment, an anaysis of the
principal solar neutrino experiments, and a discussion of how solar
neutrino experiments can be used to detect the collapse of stars in
the Galaxy. A description of how the Ga-71 experiment can be used to
decide whether the origin of the present discrepancy between theory
and observation lies in conventional solar models or conventional
physics is presented.
Title: Predicted star counts in selected fields and photometric bands
Applications to galactic structure, the disk luminosity function,
and the detection of a massive halo.
Authors: Bahcall, J. N.; Soneira, R. M.
Bibcode: 1981ApJS...47..357B
Altcode:
Tables are presented of predicted star counts in 17 selected directions
on the sky as a function of apparent B, V, R, and I magnitudes and
absolute visual magnitudes calculated from the Bahcall-Soneira Galaxy
model. It is noted that eight of the fields were selected ab initio
for their usefulness in determining from star counts either parameters
of galactic structure, the faint end of the disk luminosity function,
or the detection of a massive stellar halo. Star counts in specified
fields to mI = 19 mag are able to reveal the faint end of the
disk luminosity function down to the end of the hydrogen-burning main
sequence. It is thought that star counts at high galactic latitudes
to mI = 22 mag should reveal the stellar constituents of a
massive halo if they are massive enough to be on the hydrogen-burning
main sequence.
Title: Dust-sensitive forbidden line ratios
Authors: Draine, B. T.; Bahcall, J. N.
Bibcode: 1981ApJ...250..579D
Altcode:
The paper studies observations of certain pairs of forbidden emission
lines in the redshifted spectra of intrinsically bright objects, which
may make possible the study of dust at large distances. The forbidden
line pairs most likely to be useful in detecting dust in both galactic
and extragalactic objects are presented, and forbidden O III 2322,
4364 A, which is the best line pair for the ground-based detection of
dust intermediate-redshift quasars is discussed. Spectrophotometric
observations at 1-2 microns could permit the study of dust toward highly
luminous quasars at redshifts as large as 5, and quasars brighter than
visual magnitude 17 are presented as candidates for studying dust with
forbidden O III 2322, 4364 A.
Title: 81Br and 79Br as detectors of solar
neutrinos
Authors: Bahcall, John N.
Bibcode: 1981PhRvC..24.2216B
Altcode:
Uncertainties in nuclear matrix elements that are important for
the interpretation of proposed bromine solar neutrino experiments
are evaluated. Some laboratory measurements that could reduce
these uncertainties are suggested. The question of what can be
learned about the interior of the sun by performing a bromine
solar neutrino experiment is discussed with the aid of neutrino
absorption cross sections that are calculated using simplifying
assumptions. RADIOACTIVITY 79Br, 81Br calculated
neutrino absorption cross sections. 81Kr excited states
considered.
Title: The distribution of stars to V = 16th magnitude near the north
galactic pole - Normalization, clustering properties, and counts in
various bands.
Authors: Bahcall, J. N.; Soneira, R. M.
Bibcode: 1981ApJ...246..122B
Altcode:
The distribution on the sky of stars brighter than V= 16 mag near the
North Galactic Pole is discussed. The available data are reviewed; the
most important new data are from the catalog of Weistrop. All of the
data are in agreement with predictions made from our standard Galaxy
model when the giants are treated separately from the main sequence
stars. Transformations between different photometric bands,
including U, B, J, F, V, R, I, g, and r, are given for a wide range
of stellar types and luminosity classes. The necessary ingredients
are provided for making color transformations to arbitrary bands that
may be defined in the future with characteristic wavelengths between
4000 and 8500 A. Some illustrative applications are made to bands that
are defined for Space Telescope instruments. The star counts are
predicted in all of the above listed bands down to 16th magnitude using
the data of Weistrop with the color corrections of Faber et al. The clustering properties of the stars are investigated with the aid
of the two-point correlation function and the distributions of first
and second-nearest neighbors, as well as photometric parallaxes. A
significant fraction (∼15%) of the stars appear to be in binaries
or triplets with a typical separation of order 0.1 pc.
Title: X-ray absorption and the POST - auger decay spectrum of
multielectronatoms.
Authors: Shapiro, P. R.; Bahcall, J. N.
Bibcode: 1981ApJ...245..335S
Altcode:
Auger ionization frequently leaves an atom in an excited state which
decays to the ground state by a spontaneous radiative cascade. This
process has not previously been considered and is potentially important
as a source of line emission following X-ray absorption. We show that
the post-Auger decay yields a rich spectrum of UV and optical emission
lines as a direct signature of the X-ray absorption. Our results
are applied to some astrophysical problems of interest. We show that
the direct X-ray-induced emission considered here may contribute to
the UV line spectra of quasars and Seyfert galaxies, as well as those
of Galactic compact X-ray sources. We also find that the neutral gas
responsible for the absorption turnover in the soft X-ray spectrum of
the Crab Nebula may be a detectable source of neutral oxygen fluorescent
Kα emission at 0.525 keV if the gas is local to the nebula. The same
gas should be undetectable in its O III post-Auger decay lines.
Title: Methods for determining the masses of spherical
systems. I. Test particles around a point mass.
Authors: Bahcall, J. N.; Tremaine, S.
Bibcode: 1981ApJ...244..805B
Altcode:
Mass estimators for spherical systems may be based either on the virial
theorem or on moments of the projected mass q= (projected distance)
× (radial velocity)2/G. The statistical characteristics
of both estimators are derived and discussed for the special case
of test particles bound to a massive central object. We illustrate
their relative merits by a series of Monte Carlo experiments. We
find that the projected mass method is generally more reliable
than the virial theorem. We apply our results to three systems:
3C 273, Ml0l, and M3l. The mass of 3C 273 is estimated to be 5 ×
l013h-1 Msun from radial velocities of
companion galaxies measured by Stockton. The mass of M101 within ∼400
kpc is found to be about 2 × l012 Msun. The
mass of M3l within ∼100 kpc is found to be about 1 × 1012
Msun, an order of magnitude larger than given by the virial
theorem from the same data, but consistent with the optical and 21 cm
rotation curves.
Title: Solar Neutrinos: Present Status
Authors: Bahcall, J.
Bibcode: 1981neu1.conf....1B
Altcode:
No abstract at ADS
Title: Solar Neutrinos: Rapporteurs Talk
Authors: Bahcall, J. N.
Bibcode: 1981neu2.conf..253B
Altcode:
No abstract at ADS
Title: Guide star probabilities.
Authors: Soneira, R. M.; Bahcall, J. N.
Bibcode: 1981NASCR3374.....S
Altcode:
No abstract at ADS
Title: Solar neutrinos.
Authors: Bahcall, J. N.
Bibcode: 1981PrPNP...6..111B
Altcode:
Studies of solar neutrinos as a tool to understanding the evolution and
working nuclear processes in the interiors of stars are reviewed. Fusion
reaction models for stellar interiors are described, noting the
0.81 MeV proton-proton reaction which produces neutrinos, and the
Brookhaven experiment designed to study reactions produced by solar
neutrino capture. A neutrino was posited to be captured by Cl-37
to yield Ar-37 and an electron. The experiment involved a 400,000
l tank of perchloroethylene situated 1500 m underground to shield
from cosmic rays. Insufficient neutrinos were detected to establish a
distinction from cosmic ray neutrinos. Further experiments comprising
counting from Ga-71, Rb-87, In-115, and Tl-205 reactions occurring
from solar proton-proton and proton + electron + H2 + nu reactions are
outlined, and are shown to be dependent on conservation of electric
charge. Finally, the detection of stellar collapses is discussed.
Title: Guide star probabilities
Authors: Soneira, R. M.; Bahcall, J. N.
Bibcode: 1981ias..rept.....S
Altcode:
Probabilities are calculated for acquiring suitable guide stars (GS)
with the fine guidance system (FGS) of the space telescope. A number of
the considerations and techniques described are also relevant for other
space astronomy missions. The constraints of the FGS are reviewed. The
available data on bright star densities are summarized and a previous
error in the literature is corrected. Separate analytic and Monte Carlo
calculations of the probabilities are described. A simulation of space
telescope pointing is carried out using the Weistrop north galactic
pole catalog of bright stars. Sufficient information is presented so
that the probabilities of acquisition can be estimated as a function of
position in the sky. The probability of acquiring suitable guide stars
is greatly increased if the FGS can allow an appreciable difference
between the (bright) primary GS limiting magnitude and the (fainter)
secondary GS limiting magnitude.
Title: The effects of X-ray absorption on the spectra of distant
objects.
Authors: Shapiro, P. R.; Bahcall, J. N.
Bibcode: 1980ApJ...241....1S
Altcode:
The X-ray absorption spectrum above 0.1 keV that would be introduced
into the continuous X-ray spectrum of a quasar by an intervening
uniform, hot intergalactic gas with a small admixture of atoms of C,
N, O, Ne, Mg, Si, S and Fe has been calculated in detail. This work is
relevant to the well-known search for cosmologically distributed missing
mass. The results indicate that soft X-ray absorption can be appreciable
for all quasar X-ray sources, from the most distant to the very nearby,
for a significant range of IGM temperatures, densities, heavy-element
abundances, and observed photon energies. A brief comparison with
the preliminary results of the Einstein Observatory quasar sample is
made. The possibility that gas 'clumped' on noncosmological scales
produces observable absorption lines and/or edges in quasar X-ray
spectra is also considered.
Title: The Space Telescope Observatory
Authors: Bahcall, J. N.; Odell, C. R.
Bibcode: 1980srst.coll....5B
Altcode: 1980IAUCo..54....5B; 1979STIN...8022131B
A guide to the expected characteristics of the space telescope
(ST) observatory is presented. The general objectives of the ST
observatory are summarized. The plans for the development of the
observatory are described with a brief history of the scientific
activities; an account of the scope of the present program; a summary
of the major responsibilities of the contractors; and a list of the
project milestones are included. The performance characteristics of
the observatory are provided including the imaging and stray light
characteristics, pointing capability, and operational access. The
expected performance characteristics of all six of the first generation
science instruments are summarized. The mode of operations is described
which includes a discussion of program options, guide star selection,
methods of acquisition, and quick look data capabilities.
Title: Absorption Lines in the Spectra of Distant Objects
Authors: Bahcall, J. N.
Bibcode: 1980srst.coll..215B
Altcode: 1979srst.coll..215B; 1979srst.nasa..215B; 1980IAUCo..54..215B
Studies that can be carried out with the Space Telescope of absorption
line systems which may be expected to occur in the spectra of
distant objects are discussed. The phenomenology of quasar absorption
line systems is described and the principal suggested explanations
are summarized. It is proposed that the numerous Ly-alpha systems
are caused by 'extremely large hydrogenic halos around galaxies or
clusters of galaxies. Two tests are also described for the origins of
known absorption systems, the results of which will favor either the
cosmological or intrinsic hypothesis. Absorption lines that are likely
to be strongest are listed and a sample observing program is presented.
Title: The effect of variability on the V/V-max test
Authors: Bahcall, J. N.
Bibcode: 1980ApJ...240..377B
Altcode:
Knowledge of the distribution of quasars in space has been obtained
primarily from applications of the V/V-max test to complete flux-limited
samples of sources. The intrinsic luminosities of many quasars are
variable. Other objects, such as X-ray or gamma-ray sources, for which
one might wish to use the V/V-max test are also variable. However,
previous formulations of the V/V-max test have not included the
effects of variations. We generalize the V/V-max test to include
explicitly the effects of variability and estimate the biases that
can be introduced by the treatment of luminosity variations. Random
photometric observations have the same effects on the expected value of
V/V-max as do luminosity variations and are therefore included in the
discussion. We distinguish between archival identifications (made on
previously existing photographs) and contemporaneous identifications
(made at the same time as the basic flux measurements are carried
out). For contemporaneous identifications, the effects of flux
variability and broad luminosity function can be avoided entirely by the
use of density-weighted volumes that are corrected for source evolution.
Title: The universe at faint magnitudes. I. Models for the Galaxy
and the predicted star counts.
Authors: Bahcall, J. N.; Soneira, R. M.
Bibcode: 1980ApJS...44...73B
Altcode:
A detailed model is constructed for the disk and spheroid components
of the Galaxy from which the distribution of visible stars and mass
in the Galaxy is calculated. The application of star counts to the
determination of galactic structure parameters is demonstrated. The
possibility of detecting a halo component with the aid of star counts
is also investigated quantitatively. The stellar luminosity
functions and scale heights are determined from observations in the
solar neighborhood. The global distribution of matter is assumed,
based on studies of other galaxies, to be an exponential disk plus a
de Vaucouleurs spheroid. The spheroid luminosity function is found to
have the same shape as the disk luminosity function over the range
of absolute magnitudes (+4 to + 12) that contributes significantly
to the star counts for mV ≤ 30. The density of spheroid
stars in the solar neighborhood is 1/800 of the value for the disk. The
star counts calculated using the density variation of a de Vaucouleurs
spheroid are consistent with the available data; the counts predicted
with the aid of a Hubble law are inconsistent with observations at
more than the two-sigma level of significance. The variations
of the calculated star densities with apparent magnitude, latitude,
and longitude agree well with the available star count data for the
observationally well studied range of 4 ≲ mV ≲ 22. The
calculated (B - V) color distributions are also in good agreement with
existing data. The color data also indicate that QSOs comprise only a
few percent of the total number of stellar objects to mV
= 22 (mB = 22.5). The spheroid component is found to be
approximately spherical. The scale lengths of the Galaxy model and
computed total luminosity and M/L ratios for the disk and spheroid
are in agreement with observations of other Sbc galaxies. Illustrative
Fig. and a table of interesting characteristics (such as the mass and
luminosity contained within various radii and the escape velocity)
are provided. Further ground-based observations at attainable
faint magnitudes (mV ≤ 23 mag) would be important. Star
counts and (B - V) colors in several widely separated selected fields
would permit a more accurate determination of the disk scale length and
the spheroid star density and ellipticity. The most effective regions
in which to make these observations are specified. The Galaxy
model of the disk and spheroid is used to predict the star densities
(in B and V) that may be observable with the aid of the Space Telescope
down to very faint magnitudes. The stellar density to mV =
28 from the disk and spheroid is predicted to be 104 stars
per square degree at the galactic pole. The predicted star counts are
insensitive to many of the model parameters, although drastic changes in
the shape of the luminosity function outside the presently determined
magnitude range could produce measurable departures from the predicted
star counts at faint magnitudes. The rotation curve computed
solely from the disk and spheroid components decreases beyond about
10 kpc from the center of the Galaxy. A halo with even a relatively
small mass density in the Solar neighborhood (ρHalo
(Sun) = 0.01 Msun pc-3) can give rise to a flat
rotation curve. The stellar content of such a halo would be revealed by
observations with Space Telescope cameras if the halo consists of main
sequence stars with MV ≲ 19.0 mag (existing observations
imply MVMS ≳ 14.0 mag) or faint white dwarfs
with MVWD ≲ 17.5 mag (existing observations
imply MVWD ≳ 13.0 mag). Existing data imply
(M/L)Halo ≳650 (Solar Visual units). The results for
V magnitudes are described in the main text; the corresponding results
for B magnitudes are summarized in Appendix A. A table of predicted
differential and integrated star counts for both V and B magnitudes
is given in Appendix B. Simple formulae that reproduce to an accuracy
of 15% the predicted model star densities as a function of magnitude,
latitude, and longitude are also provided in Appendix B.
Title: New Solar-Neutrino Flux Calculations and Implications Regarding
Neutrino Oscillations
Authors: Bahcall, J. N.; Lubow, S. H.; Huebner, W. F.; Magee, N. H.,
Jr.; Merts, A. L.; Argo, M. F.; Parker, P. D.; Rozsnyai, B.; Ulrich,
R. K.
Bibcode: 1980PhRvL..45..945B
Altcode:
The results of new calculations of solar-neutrino fluxes are
presented; the fluxes are obtained from detailed solar models that
make use of improved opacities and nuclear-physics cross sections. By
evaluating known uncertainties in the predicted capture rate for the
37Cl solar-neutrino experiment, we find that the ratio of
theoretical to (best-estimate) observed capture rate lies in the range
4.0 to 2.6. These results constitute a strong constraint on models
of neutrino oscillations if the entire discrepancy is ascribed to
neutrino oscillations.
Title: The Space Telescope Observatory.
Authors: Bahcall, J. N.; Odell, C. R.
Bibcode: 1980JAnSc..28..107B
Altcode:
The Space Telescope is an international astronomical observatory
which will be placed into a low earth orbit in December 1983. The
observatory will provide astronomers the opportunity to use five
different instruments (wide field/planetary camera, faint object camera,
high-resolution spectrograph, faint-object spectrograph, and high speed
photometer), and to do astrometry with the use of the fine guidance
sensors used primarily for pointing control. These instruments, the
spectral range available above the earth's atmosphere, and the spatial
resolution available from the combination of a near-diffraction limited
94-in. primary mirror and the stability provided by the Pointing Control
System provide a tremendous potential to the astronomical community.
Title: Star counts as an indicator of galactic structure and quasar
evolution
Authors: Bahcall, J. N.; Soneira, R. M.
Bibcode: 1980ApJ...238L..17B
Altcode:
A detailed model of the stellar content of the Galaxy is described
briefly. Illustrative applications of the model are made, using
existing data, to indicate how star counts can be used to determine
some parameters of galactic structure, to detect a massive (stellar)
halo, and to constrain models of quasar evolution.
Title: On the simultaneous analysis of several complete samples. The
V/Vmax and Ve/Va variables, with applications to quasars.
Authors: Avni, Y.; Bahcall, J. N.
Bibcode: 1980ApJ...235..694A
Altcode:
Methods are derived for applying the V/Vmax variable when several
complete samples are analyzed simultaneously. A new, related,
variable, V(e)/V(a), which is superior to V/Vmax when sufficient
observational data are available, is introduced. It is shown how
statistically independent complete samples can be generated from
partially overlapping samples such that each observed object appears
only once in the analysis. These methods make it possible to combine the
information from different complete samples, and to make an efficient
use of all available data. Illustrative examples for quasars are
given. It is shown how the generalized V/Vmax and V(e)/V(a) can be
used to find the amount of cosmological evolution of quasars and its
associated range of uncertainty.
Title: The magnetic dipole model for superluminal radio sources
Authors: Bahcall, J. N.; Milgrom, M.
Bibcode: 1980ApJ...236...24B
Altcode:
The magnetic dipole model (MAD) for superluminal radio sources is
described in detail. Analytic derivations are presented for a number
of observationally accessible kinematic quantities, as well as for the
size and shape of the radio lobes and the probability distributions
for the velocities. The results are in satisfactory agreement with
observations. The astrophysical aspects of MAD are discussed assuming
that the dominant emission mechanism is curvature radiation. The
possibility that the local radius of curvature of the magnetic field
is much smaller than the curvature radius of an ideal dipole field is
considered. The physical effects that are discussed include coherent
emission and absorption, circular and linear polarization, and inverse
Compton scattering. The time-dependence of the flux and the shape of
the spectrum that are deduced on the basis of the assumed emission
mechanism are consistent with observation.
Title: Solar Neutrinos
Authors: Bahcall, J. N.
Bibcode: 1980aepc.conf...25B
Altcode:
No abstract at ADS
Title: The Effects of X-ray Absorption on the Spectra of Distant
Objects
Authors: Shapiro, P. R.; Bahcall, J. N.
Bibcode: 1979BAAS...11..694S
Altcode:
No abstract at ADS
Title: Models for the Galaxy and the Predicted Star Counts
Authors: Bahcall, J. N.; Soneira, R. M.
Bibcode: 1979BAAS...11..706B
Altcode:
No abstract at ADS
Title: Solar Neutrinos: Theory Versus Observation
Authors: Bahcall, John N.
Bibcode: 1979SSRv...24..227B
Altcode:
The current state of the solar neutrino problem is described. The
predictions of solar models (standard and nonstandard) are reviewed. The
neutrino absorption cross sections for all detectors of current
interest are reviewed with special emphasis on the uncertainties that
exist in the calculations for each target. A long-term program for
neutrino spectroscopy of the solar interior is outlined. It is shown,
in addition, that stellar collapses can be detected within the galaxy
by the proposed solar neutrino detectors.
Title: The Effects of X-ray Absorption on the Spectra of Distant
Objects.
Authors: Shapiro, P. R.; Bahcall, J. N.
Bibcode: 1979BAAS...11..778S
Altcode:
No abstract at ADS
Title: The Space Telescope Observatory.
Authors: Bahcall, J. N.; Odell, C. R.
Bibcode: 1979NASCP2111....5B
Altcode: 1979STIN...7927043B
The purpose of this review is to provide a convenient guide to the
expected characteristics of the Space Telescope Observatory for
astronomers and physicists. The authors have tried to provide enough
detail so that a professional scientist, observer or theorist, can plan
how the observatory may be used to further his observing program or to
test theoretical models. Further detail is available in NASA documents
that are referenced throughout the report.
Title: Absorption lines in the spectra of distant objects.
Authors: Bahcall, J. N.
Bibcode: 1979NASCP2111..215B
Altcode:
The author discusses studies that can be carried out with the Space
Telescope of absorption-line systems which may be expected to occur
in the spectra of distant objects.
Title: Solar neutrino experiments
Authors: Bahcall, John N.
Bibcode: 1978RvMP...50..881B
Altcode:
New results are presented for absorption cross sections of nine
possible detectors of solar neutrinos (7Li, 37Cl,
51V, 55Mn, 71Ga, 81Br,
87Rb, 115In, and 205Tl). Special
attention is given to nuclear physics uncertainties. The calculated
cross sections are used (with the aid of illustrative solar models
and ad hoc assumptions about neutrino propagation) to discuss what
can be learned about the sun or weak interactions from each of the
nine suggested solar neutrino experiments. An experimental program
for neutrino spectroscopy of the solar interior is outlined. It is
shown in addition that stellar collapses can be detected to typical
distances of several kpc (kiloparsecs) by the proposed 7Li,
37Cl, and 115In solar neutrino detectors (provided
that electron neutrinos do not decay or oscillate).
Title: Apparent superluminal expansion velocities in the dipole
magnetic field model
Authors: Milgrom, M.; Bahcall, J. N.
Bibcode: 1978Natur.274..349M
Altcode:
Observations of compact radio sources conducted with very long baseline
interferometry methods have shown that the components of some radio
sources seem to move apart with relative velocities more than twice
the speed of light. A model for compact extragalactic radio sources
presented by Sanders is considered (1974). In this model apparent
superluminal expansion arises naturally and radiating particles move
at relativistic velocities along dipole magnetic field lines. Sanders
discusses the relationship of this proposal to other explanations
of superluminal velocities in compact radio sources. However, he
incorrectly evaluated the consequences of the dipole field model,
obtaining results both for the magnitude of the expansion velocity
and its time dependence that are in conflict with observations. An
investigation is conducted in which the valid geometrical consequences
of the model are presented. It is shown that these consequences agree
with available observations.
Title: Proposed solar-neutrino experiment using 71Ga
Authors: Bahcall, J. N.; Cleveland, B. T.; Davis, R., Jr.; Dostrovsky,
I.; Evans, J. C., Jr.; Frati, W.; Friedlander, G.; Lande, K.; Rowley,
J. K.; Stoenner, R. W.; Weneser, J.
Bibcode: 1978PhRvL..40.1351B
Altcode:
A solar-neutrino experiment that uses 71Ga as a detector can
distinguish between broad classes of explanations for the discrepancy
between prediction and observation in the 37Cl experiment. A
radiochemical experiment with the required amount of 71Ga
is feasible.
Title: The Hubble diagrams for quasars.
Authors: Bahcall, J. N.; Turner, E. L.
Bibcode: 1978PhyS...17..353B
Altcode:
The optical Hubble diagram for a complete sample of 112 quasars is
constructed for q(0) = 1. With no correction for selection effects,
the Hubble diagram shows a strong correlation of magnitude with
redshift (slope 4.43 plus or minus 0.44; correlation coefficient
of 0.956). These uncorrected results place an interesting limit on
luminosity evolution. The optical and radio Hubble diagrams are also
discussed after applying the proper corrections for selection effects.
Title: On the origin of quasar absorption lines.
Authors: Bahcall, J. N.
Bibcode: 1978PhyS...17..229B
Altcode:
Many predictions have been made on the basis of the cosmological
hypothesis for the origin of quasar absorption lines. The observational
evidence relating to these predictions is summarized. It appears likely
that many of the observed absorption lines originate in material that
is separated from the emitting quasar by cosmological distances. Two
special problems are briefly discussed: the interpretation of redshift
splittings and the origin of absorption redshifts larger than their
associated emission redshifts.
Title: X-ray line spectroscopy for clusters of galaxies. I.
Authors: Bahcall, J. N.; Sarazin, C. L.
Bibcode: 1978ApJ...219..781B
Altcode:
Theoretical models for the intracluster gas in X-ray clusters of
galaxies are studied. The limits of validity of all the published models
are derived from self-consistent arguments and existing data. Results
are presented for the well model (gas trapped in the potential well
of a single galaxy) and the wind model. A scaling law is proved that
allows one to apply the results calculated for spherical systems to the
nonspherical groupings that are often observed. The particular line
intensities that can best be used to discriminate among theoretical
models or to diagnose the gas (i.e., determine abundances, temperatures,
ionization state, and other properties) are listed along with the
required experimental sensitivity and resolution. Possible observing
programs are described that can be carried out with existing instruments
on currently operating satellites and with future space experiments
(e.g., on HEAO-A, HEAO-B, and other planned X-ray missions).
Title: Theoretical Introduction to the 37Cl Solar Neutrino
Experiment
Authors: Bahcall, J. N.
Bibcode: 1978sfsn.conf...55B
Altcode:
No abstract at ADS
Title: Masses of neutron stars and black holes in X-ray binaries.
Authors: Bahcall, J. N.
Bibcode: 1978ARA&A..16..241B
Altcode:
A coherent summary is presented of the methods used to determine
the masses of X-ray sources in binary systems, and the presently
available results are described. The elements of the analysis are
considered, taking into account X-ray and optical mass functions,
the equipotential surfaces of the optical primaries, eccentric orbits,
X-ray eclipse durations, rotational velocities of the optical primaries,
and ellipsoidal light variations. The mass determinations are discussed
for six X-ray sources in binary systems which have been extensively
studied. The systems include 3U 0900-40, SMC X-1, Cen X-3, Her X-1,
3U 1700-37, and Cyg X-1.
Title: Theoretical Introduction to the 37CI Solar-neutrino
Experiment
Authors: Bahcall, J. N.
Bibcode: 1978ComAp...8...37B
Altcode: 1978STIA...7924515B
At the present time, within the framework of the observational
information about stars, only the Cl-37 experiment is clearly
inconsistent with the standard theory of stellar evolution. With a
minimum of technical detail and calculations, the author tries to
explain the relevance of the Cl-37 experiment to theories of stellar
evolution and nuclear-energy generation. The basic neutrino-producing
p-p reaction and the pep line are reviewed, and their role in a typical
solar model is explained. The expected flux of solar neutrinos is
about 5 SNU for the standard theory of stellar evolution. In any case,
it predicts too large a B-8 flux.
Title: Optical properties of binary X-ray sources
Authors: Bahcall, J. N.
Bibcode: 1978pans.proc...63B
Altcode:
The paper attempts to summarize in a convenient form the present
state of experimental knowledge on the optical properties of binary
X-ray sources, and to draw attention to the most important problems in
which observational progress can be made with current techniques. The
basic observational techniques which have been applied to this study
are described, including spectroscopic classification, photometry,
IR measurements, and polarization measurements. Attention is given
to the following systems: Cygnus X-1/HDE 226868; Cen X-3; Sanduleak
160/SMC X-1; Hz Herculis/Her X-1; V 818 Sco/Sco X-1; Cygnus X-3;
HD 77581/Vela XR-1; and HD 153919/3U 1700-37.
Title: Capture Rates for Various Solar Neutrino Detectors
Authors: Bahcall, J. N.
Bibcode: 1978sfsn.conf..223B
Altcode:
No abstract at ADS
Title: Solar neutrinos
Authors: Bahcall, J. N.
Bibcode: 1977AIPC...37...53B
Altcode:
No abstract at ADS
Title: A Model for Superluminal Radio Sources
Authors: Bahcall, J. N.; Milgrom, M.
Bibcode: 1977BAAS....9..586B
Altcode:
No abstract at ADS
Title: Neutrino absorption cross sections for 37Cl with
applications.
Authors: Bahcall, J. N.
Bibcode: 1977ApJ...216L.115B
Altcode:
Neutrino absorption cross sections for Cl-37 are
calculated. Applications are made to problems involving solar neutrinos,
collapsing stars, and the cosmic neutrino mass density. The present
Brookhaven experiment can detect stellar collapses as far away as 5
kpc for plausible collapse parameters.
Title: On the Zeeman splitting of X-ray lines by neutron-star
magnetic fields.
Authors: Sarazin, C. L.; Bahcall, J. N.
Bibcode: 1977ApJ...216L..67S
Altcode:
In the strong magnetic fields usually assumed to exist near neutron
stars (of the order of 100 billion to 10 trillion gauss), X-ray emission
lines may exhibit easily detected Zeeman splitting (at least when the
field in the emission region does not exceed approximately 500 billion
gauss). Detection of this splitting would allow a direct measurement of
the neutron-star magnetic-field strength. The observed Zeeman pattern
would determine the direction of the magnetic field; in an oblique
rotator, the pattern would alternate with the pulsar period.
Title: The star distribution around a massive black hole in a globular
cluster. II. Unequal star masses.
Authors: Bahcall, J. N.; Wolf, R. A.
Bibcode: 1977ApJ...216..883B
Altcode:
The steady-state distribution of stars around a massive black hole in
a globular cluster is determined by solving numerically the coupled
time-dependent Boltzmann equations for a system containing stars of
two different masses. Similar results are found for an arbitrary
spectrum of masses with the aid of approximate analytic solutions
of the time-independent equations. The effects of mass segregation
are summarized by scaling laws that are derived both by analytic
approximations and by numerical solutions. The detectability of a
black hole in a globular cluster is discussed in terms of possible
observations of the central star distributions.
Title: X-ray line emission for clusters of galaxies. II. Numerical
models.
Authors: Sarazin, C. L.; Bahcall, J. N.
Bibcode: 1977ApJS...34..451S
Altcode:
The predicted X-ray spectra of clusters of galaxies have been calculated
assuming that the X-ray emission arises from hot intracluster gas in
collisional ionization equilibrium. An extensive grid of models is
presented for isothermal models, polytropic hydrostatic models, and
wind models. The integrated X-ray spectrum is given for each model,
including line and recombination radiation. The intensities of satellite
lines due to dielectronic recombination and inner-shell excitation are
also presented; these satellites can be used to derive the temperature
and ionization state of the gas. The projected distributions on the
sky of continuum X-ray intensity, line strengths and line widths, and
the satellite intensities are given as a function of projected radius
from the cluster center. The predicted microwave diminution has been
calculated as a function of cluster position. The observable X-ray
emission properties scale simply with cluster parameters; relations
are given for deriving the predicted X-ray properties from other
observations.
Title: On the mass determination of Hercules X-1.
Authors: Bahcall, J. N.; Chester, T. J.
Bibcode: 1977ApJ...215L..21B
Altcode:
Middleditch and Nelson (1976) obtained a value of 1.30 + or - 0.14
solar masses for the mass of Her X-1 on the basis of the observed
frequencies of the optical pulsations due to absorption, reprocessing,
and reemission of pulsed X-ray energy from the surface of HZ Her. A
more conventional estimate of the uncertainty in the mass inferred for
Her X-1 from the cited optical-pulsation data is computed using those
data in combination with a simple geometrical model for the optical
pulsations and Uhuru X-ray observations of the mass function and the
half-angle of the eclipse duration of the HZ Her/Her X-1 system. It
is assumed that the surface of HZ Her is an equipotential surface of
the restricted three-body potential and that HZ Her just fills its
critical equipotential. The allowed ranges of masses obtained are 0.6
to 2.0 solar masses for Her X-1 and 1.6 to 2.7 solar masses for HZ
Her. It is found that the calculated mass of Her X-1 is especially
sensitive to the unknown rotational velocity of HZ Her.
Title: Parameters and predictions for the X-ray emitting gas of Coma,
Perseus, and Virgo.
Authors: Bahcall, J. N.; Sarazin, C. L.
Bibcode: 1977ApJ...213L..99B
Altcode:
The range of acceptable models for the intracluster gas in the Coma,
Perseus, and Virgo clusters is determined from previous observations of
the spectrum, intensity, and size of the cluster X-ray sources. Standard
hydrostatic, wind, and inflow models are considered. For Virgo, a 'well'
model is proposed in which the gas is trapped in the gravitational
potential of M87, assumed to be very massive and extended. The iron
abundance in the intracluster gas is determined from the observed
strength of the 7-keV line feature; the required abundances for
all models and all clusters are approximately equal and solar in
value. The similarity of the abundances derived for these three clusters
suggests that the line emission probably arises from the intracluster
gas. Predictions are given for the cosmic microwave diminution and the
dependence of X-ray size on observed energy for acceptable models for
the intracluster gas.
Title: The Hubble Diagrams for Quasars
Authors: Bahcall, J. N.; Turner, E. L.
Bibcode: 1977IAUS...74..295B
Altcode:
No abstract at ADS
Title: Circumstellar matter in the binary V Puppis.
Authors: York, D. G.; Flannery, B.; Bahcall, J.
Bibcode: 1976ApJ...210..143Y
Altcode:
Results are reported for Copernicus observations of the double-lined
binary V Puppis in the wavelength region from 1155 to 1310 A with a
resolution of 0.2 A. The sharp-lined UV absorption spectrum is found
to provide a line of sight dominated by an apparently 'textbook'
H II region in a Stromgren sphere surrounding the stars. Several
characteristics of this H II region are deduced by analyzing absorption
features arising from excited fine-structure states of N II and Si
II. Evidence is given for the presence of a normal interstellar H
I region containing H2 and a separate H I region which could be the
transition zone of the H II region. A possible blueshifted N V feature
is noted in absorption. It is suggested that the H(+) emission measure
and a characteristic size and shape for the H II region can probably
be determined by optical observations of Balmer recombination lines
within about 1 deg of V Puppis.
Title: The sun's missing particles
Authors: Bahcall, J. N.
Bibcode: 1976NatH...85...76B
Altcode:
Attention is focused on the theoretical puzzle and crisis in solar
physics provoked by discrepancies between results of the Davis-Evans
neutrino trap experiment and theoretical predictions. The importance
of neutrinos in current theory on the sun's heat production mechanisms
(including sustained thermonuclear fusion as energy source) is explained
and the Davis-Evans Brookhaven neutrino detector is described. A
computer model of the solar interior is sketched. Conjectures advanced
to challenge existing theory and account for the anomalous neutrino
evidence are sketched (thermonuclear fusion reactions downgraded; black
hole at center of sun; lower estimate of temperature of solar interior;
higher content of heavy elements in solar interior; extremely high
central magnetic fields; immiscibility of hydrogen and helium below
some critical temperature; neutrino decay by unknown modes)
Title: Star distribution around a massive black hole in a globular
cluster.
Authors: Bahcall, J. N.; Wolf, R. A.
Bibcode: 1976ApJ...209..214B
Altcode:
The distribution of solar-mass stars around a massive black hole
in a globular star cluster is investigated using a basic physical
picture in which stars in bound orbits in the gravitational potential
well of the black hole diffuse from one bound orbit to another via
star-star gravitational scattering. Detailed expressions are derived
for the relevant diffusion coefficients, the time-dependent Boltzmann
equation is solved numerically, and solutions are found which satisfy
the boundary conditions at both zero and large binding energy. The
results indicate that the distribution function is approximately a
power law throughout most of the black hole's gravitational well,
that stars in bound orbits diffuse slowly down the gravitational well
under equilibrium conditions, and that a black hole of less than or
approximately 1000 solar masses may accrete stars primarily by capture
from unbound orbits. Several methods for detecting massive black holes
in cores of globular clusters are discussed along with expected large
statistical fluctuations close to the black hole and the possible
relevance of various stellar accretion processes for globular-cluster
X-ray sources.
Title: Search for X-ray emission from globular clusters using
Uhuru data.
Authors: Ulmer, M. P.; Murray, S. S.; Gursky, H.; Bahcall, J. N.
Bibcode: 1976ApJ...208...47U
Altcode:
We searched the Uhuru data for X-ray emission from 40 globular
clusters. We were unable to extend the list of known globular cluster
X-ray sources (NGC 1851, 6440, 6441, 6624, and 7078). Our 3 a upper
limits ranged from 2 x 10 ergs 1 to 1036 ergs 1 (2-10 keV). Subject
headings: clusters: globular - X-rays: sources
Title: X-ray pulses from globular clusters
Authors: Bahcall, J. N.; Ostriker, J. P.
Bibcode: 1976Natur.262...37B
Altcode:
GIANT X-ray pulses have been observed recently by several
groups1-7 from sources located in a number of celestial
positions. Two of these sources may plausibly be identified with
the globular cluster X-ray sources: NGC6624 and NGC1851. In several
cases2,7 the pulses seem to occur in approximately periodic
sequences; in other sources the intervals are irregular, but in one case
there is a relation between pulse strength and interpulse interval. The
non-burst behaviour of globular cluster X-ray sources has been
interpreted8,9 in terms of massive (≳ 103Msolar)
black holes powered by accretion from a disk supplied by cluster gas. We
suggest here that compact stars bound to the central massive black
hole and orbiting through the accretion disk may produce, by several
possible mechanisms, giant pulses. These pulses might be expected to
exhibit a variety of types of X-ray behaviour corresponding to the
uncertain characteristics (for example, density and spatial extent)
of the individual accretion disks at the different points at which the
orbits of the bound compact stars intersect the disks. We note that
there may be more than one class of sources of giant X-ray bursts and
that our speculation refers only to those sources in globular clusters.
Title: X-ray Sources in Globular Clusters
Authors: Bahcall, John
Bibcode: 1976BAAS....8R.442B
Altcode:
No abstract at ADS
Title: Energy Transport in the Solar Interior
Authors: Katz, J. I.; Bahcall, J. N.
Bibcode: 1976BAAS....8..320K
Altcode:
No abstract at ADS
Title: Models for X-Ray Line Emission from Clusters of Galaxies
Authors: Bahcall, J. N.; Sarazin, C. L.
Bibcode: 1976BAAS....8..355B
Altcode:
No abstract at ADS
Title: Her X-1 panel.
Authors: Bahcall, J. N.
Bibcode: 1976NASSP.389...99B
Altcode: 1976NASSP.589...99B
No abstract at ADS
Title: Is the local supercluster a physical association?
Authors: Bahcall, J. N.; Joss, P. C.
Bibcode: 1976ApJ...203...23B
Altcode:
A quantitative measure of the degree of concentration of a sample
of galaxies toward any great circle is described and applied to the
Shapley-Ames and de Vaucouleurs catalogs of bright galaxies as well
as to computer-simulated catalogs of galaxies. It is found that the
observed distribution can be explained as the combined result of
obscuration by our Galaxy, purely local clustering on angular scales
of less than about 10 deg, and our proximity to a rather large and
populous cluster, the Virgo cluster. In order for this interpretation
to be correct, the Virgo cluster must have a mean angular radius of the
order of or greater than 15 deg. This interpretation is supported by
recent measurements which do not indicate any large inhomogeneities
in the motions of nearby galaxy clusters and which show that the
mean recessional velocity of the Virgo cluster is consistent with a
uniform Hubble expansion. If the present interpretation is correct,
it may be possible to determine the Hubble constant directly from
measurements of individual distance indicators (such as H II regions
and the brightest stars) with distance moduli less than about 32.
Title: Status of the study of ellipsoidal light variations in 3U
0900-40 and other X-ray binaries.
Authors: Avni, Y.; Bahcall, J. N.
Bibcode: 1976NASSP.389..615A
Altcode: 1976NASSP.589..615A; 1976xrbi.nasa..615A
Estimates of system parameters and component masses are reviewed. The
mass for the X-ray source in 3U0900-40 is found. The importance of
determining the X-ray eclipse duration in binary systems is explained. A
list of important observations for testing and utilizing the standard
picture is presented.
Title: Solar Neutrinos: A Scientific Puzzle
Authors: Bahcall, John N.; Davis, Raymond, Jr.
Bibcode: 1976Sci...191..264B
Altcode:
No abstract at ADS
Title: Masses for Vela X-1 and other X-ray binaries.
Authors: Avni, Y.; Bahcall, J. N.
Bibcode: 1975ApJ...202L.131A
Altcode:
A detailed analysis of the optical light curve and other previously
known observations of the X-ray binary Vela X-1 (3U 0900-40) is
reported. All constraints are consistent only with a projected orbital
velocity of the X-ray source of between 200 and 300 km/s. The allowed
ranges of the masses and other parameters are estimated. If the mass of
the X-ray source is less than the Chandrasekhar limit for white dwarfs,
then the optical star must have an unusually small mass-to-radius
ratio for its spectral type. The importance of the X-ray eclipse
duration in determining binary parameters is emphasized, and some
results are presented from analyses of observations of 3U 1700-37 and
other X-ray binaries.
Title: Splittings in quasar absorption lines.
Authors: Bahcall, J. N.
Bibcode: 1975ApJ...200L...1B
Altcode:
It is shown that the apparent constancy of the splitting between
quasar absorption lines observed by Boksenberg and Sargent could be
understood if the typical velocity in the absorbing material were
somewhat less than the observing resolution (estimated to be 100 km
per sec). If this interpretation were correct, then there should be
many more redshifts that are split with velocity separations that are
less than 100 km per sec than have been so far observed at velocity
separations of the order of 150 km per sec. The above conclusions are
independent of whether or not the absorption lines originate close to,
or very far away from, the quasar. Some results are presented for a
specific model in which the splittings are supposed due to absorption
in halos or clouds surrounding galaxies or small groups of galaxies
and some tests of this model are suggested. The model parameters are
consistent with recent radio observations of H I clouds or halos that
extend far from their parent galaxies.
Title: The unidentified high galactic latitude X-ray sources: bright
galaxies or rich clusters?
Authors: Bahcall, J. N.; Bahcall, N. A.
Bibcode: 1975ApJ...199L..89B
Altcode:
Positional correlations are analyzed among the 51 unidentified
high-galactic-latitude X-ray sources in the third Uhuru catalog,
all 2712 rich clusters of galaxies in the Abell catalog, and all
bright galaxies in the Zwicky catalog. Computer-simulated Uhuru
catalogs are used to evaluate the chance coincidence rate as well as
its dispersion, and the validity is confirmed of practically all the
previously suggested identifications of 3U sources with nearby rich
Abell clusters. It is shown that one or two of the distance-group 4
Abell clusters may be associated with 3U sources and that very few,
if any, of the 3U sources are associated with the most distant Abell
clusters. On this basis, an upper limit to the X-ray luminosity
is established which is in agreement with the highest such value
observed for nearby clusters. Although about 50% of the source error
boxes contain a bright Zwicky galaxy, very few valid identifications
are expected.
Title: Optical studies of 10 high galactic latitude X-ray sources.
Authors: Bahcall, J. N.; Bahcall, N. A.; Murray, S. S.; Schmidt, M.
Bibcode: 1975ApJ...199L...9B
Altcode:
Optical studies are reported for a representative sample of 10
unidentified high galactic latitude X-ray sources that are north of
declination minus 25 deg and that have 3U error boxes less than or of
the order of 0.5 square degrees. The source 3U 1410-03 is identified
with a peculiar emission-line spiral galaxy, NGC 5506, and a distance
group 4 rich cluster of galaxies, Abell 2142, is suggested as a
possible identification for 3U 1555+27. It is shown that very few
of the unidentified high galactic latitude sources are quasi-stellar
sources brighter than 17.5 mag, although one possible X-ray quasar,
NAB 0137-01, is reported.
Title: Massive black holes in globular clusters.
Authors: Bahcall, J. N.; Ostriker, J. P.
Bibcode: 1975Natur.256...23B
Altcode:
It is proposed that the observed X-ray emission in globular star
clusters may be caused by the accretion of gas onto a massive black
hole at the center of a cluster. The amount of accreting gas is
estimated for a model cluster together with the minimum black hole
mass and the X-ray luminosity. It is shown that the X-ray emission
should be pointlike and located at the center of the cluster, and that
there should be no eclipses and no orbital or spin periods observed
in the X-ray flux. Possible explanations are considered for the model
limitation that only a small fraction of the globular clusters in the
galaxy are X-ray sources.
Title: Copernicus - X-ray observations of 3U 9759-49.
Authors: Bahcall, J. N.; Charles, P. A.; Davison, P. J. N.; Sanford,
P. W.; Kellogg, E.; York, D.
Bibcode: 1975MNRAS.171P..41B
Altcode:
Possible associations between the weak X-ray source 3U 0750-49
and bright variable stars are investigated using X-ray data from
the Copernicus satellite on V Pup and HD 64740, two bright variable
stars within the Uhuru error box for 3U 0750-49. Analysis of the data
indicates that the X-ray source is almost certainly closer to V Pup
than to HD 64740, and the latter object is completely ruled out as
a possible candidate. An error box is derived which is perpendicular
to the Uhuru error box and of similar dimensions. Based on both error
boxes, the variable stars most likely to be the X-ray source are found
to be V Pup, CN Pup, and CSV 1199.
Title: Ellipsoidal light variations and masses of X-ray binaries.
Authors: Avni, Y.; Bahcall, J. N.
Bibcode: 1975ApJ...197..675A
Altcode:
The ellipsoidal light curves of four binary X-ray systems (HDE
226868/Cyg X-1, Sk 160/ SMC X-1, Krzeminski's star/Cen X-3, and HZ
Her/Her X-1) are analyzed assuming that the light variations are caused
by gravitational and limb-darkening effects on a tidally distorted
star. Some uncertainties regarding the validity of this interpretation
are discussed, including departures from repeatability in the light
curve and from corotation, the effects of heating and reflection, and
the possibility that the primary is inside the Roche lobe. Numerical
calculations of light curves show that Cyg X-1 can be either a black
hole or a normal early-type star with a mass not less than 9 solar
masses; the mass of SMC X-1 is about 2.3 solar masses, close to the
upper limit for a nonrotating neutron star; and the mass of Cen X-3
is between 0.6 and 1.1 solar masses. No significant constraints could
be derived from the available data for Her X-1.
Title: The Star Distribution in M15
Authors: Bahcall, J. N.; Bahcall, N. A.; Weistrop, D.
Bibcode: 1975ApL....16..159B
Altcode:
No abstract at ADS
Title: Further optical observations of HZ Herculis.
Authors: Bahcall, J. N.; Bahcall, N. A.; Herczeg, T. J.; Joss, P. C.;
Leibowitz, E. M.; Segalovitz, A.; Stolero, S.; Véron, M.; Véron,
P.; Wehinger, P. A.; Weistrop, D.; Wyckoff, S.
Bibcode: 1975PASP...87..141B
Altcode:
Optical observations of HZ Her made in the spring and summer of 1973
are presented. Some of the observations are practically coincident
with estimated turn-on times for Her X-1 and others are simultaneous
with X-ray observations made using the Copernicus satellite. Eight
magnitudes were also measured from old plates for the epoch 1953-60;
these measurements confirm the long-term variations for that epoch
reported by Jones, Forman, and Liller (1973). An interesting theoretical
explanation by Fabian, Pringle, and Rees (1973) for the persistence
of large optical variations throughout the 35-day X-ray period is
ruled out by simultaneous UHURU (X-ray) and Wise Observatory (optical)
observations.
Title: Some remarks on solar neutrinos.
Authors: Bahcall, J. N.
Bibcode: 1975ucyr.conf..131B
Altcode:
No abstract at ADS
Title: Some properties of X-ray binaries
Authors: Bahcall, J. N.
Bibcode: 1975xris.conf..147B
Altcode:
Three questions are discussed regarding the optically identified
binary X-ray sources HZ Her/Her X-1, Krzeminski/Cen X-3, and HDE
226868/Cyg X-1: (1) the origin of the observed periodicities, (2) the
estimated masses of the unobserved secondaries, and (3) the nature
of the secondaries. The main observational properties and principal
characteristics of the sources are summarized, their periodicities
are analyzed, and it is suggested that rotation may be responsible for
the periodicities. Ways to estimate the masses in the present systems
are described, and approximate values are given for the masses of
both components in each system. It is shown that Her X-1 and Cen X-3
are probably neutron stars and that Cyg X-1 must be either a normal
(nondegenerate) star or a black hole.
Title: Solar neutrinos: A scientific puzzle.
Authors: Bahcall, J. N.; Davis, R., Jr.
Bibcode: 1975PhyBl..31..609B
Altcode: 1975PhB....31..609B
No abstract at ADS
Title: Optical and near infrared observations of seven fields
containing X-ray sources
Authors: Bahcall, J. N.; Bahcall, N. A.
Bibcode: 1975xris.conf..535B
Altcode:
Optical and near-IR observations are reported for seven fields
containing strong, variable X-ray sources with small error boxes located
near the galactic center. The sources include 3U 1709-23, 1728-24,
1735-28, 1758-25, 1758-20, 1811-17, and 1837+04. The observational
methods are described, and limits of detectability are estimated for
various assumed models of optical counterparts. Two objects are found
which are possible optical counterparts for 3U 1709-23 and 1728-24. It
is noted that none of the fields contained stars within the estimated
detectability limits which exhibited large variations during the period
of observation.
Title: Review of Publications: The Redshift Controversy
Authors: Field, George B.; Arp, Halton; Bahcall, John N.
Bibcode: 1974JRASC..68..276F
Altcode:
No abstract at ADS
Title: Neutral currents and stellar cooling
Authors: Bahcall, J. N.; Treiman, S. B.; Zee, A.
Bibcode: 1974PhLB...52..275B
Altcode:
If weak neutral currents couple with the strengths suggested by
recent experiments, then stellar cooling via neutrino pair emission
from thermally excited nuclear states may be significant in white
dwarfs with central temperature <~108° K. At higher
temperatures, other neutrino cooling processes are more important. In
the sun, the decay of thermally excited 57Fe nuclei may
produce a moderately large, but probably unobservable, low-energy
flux of νμ, g¯nμ, νe, and
g¯ne neutrinos. Alfred P. Sloan Foundation Fellow.
Title: Mass Limits for the Centaurus X-3 System
Authors: Avni, Y.; Bahcall, J. N.
Bibcode: 1974ApJ...192L.139A
Altcode:
Constraints on the mass of Cen X-3 based on the observed amplitude of
the optical light curve are discussed. A 2 sigma lower limit of 0.6
solar mass is derived, assuming corotation and the interpretation of the
ellipsoidal light variations as caused by gravity- and limb-darkening
effects. Including the constraints imposed by the eclipse duration,
it is found that the mass of Cen X-3 is equal to 0.6 to 1.1 solar mass,
while the mass of its optical companion is equal to 16.5 to 18.5 solar
masses. The sensitivity of the derived masses to the assumed geometry
is demonstrated.
Title: Optical properties of HZ Herculis.
Authors: Bahcall, J. N.; Joss, P. C.; Avni, Y.
Bibcode: 1974ApJ...191..211B
Altcode:
The optical properties of HZ Her are analyzed, and several parameters of
the Her X-1-HZ Her binary system are estimated. The phase agreement of
the X-ray and optical variations, the dependence of the average optical
luminosity upon the 35-day X-ray cycle, and the energy budget of the
optical variations are studied, using recent observational data. The
period, amplitude, and phase of the small-scale optical light variations
found by Jones et al. during times of extended optical inactivity are
also investigated. The light curve and the radial-velocity variations
of HZ Her are analyzed, using several simple models for the brightness
distribution across the face of the star. The masses of Her X-1 and
HZ Her are estimated by four different methods. Subject headings:
binaries - stars, individual - X-ray sources
Title: Short-time optical variability of X-ray sources.
Authors: Avni, Y.; Bahcall, J. N.
Bibcode: 1974ApJ...191..221A
Altcode:
A formalism for interpreting the short-time optical variability caused
by X-ray heating in variable X-ray sources is presented and applied
to the following systems: Her X-1, Cen X-3, Cyg X-1, 2U 0900-40, 2U
1700-37, Sco X-1, and Cyg X-2. It is shown that the observed upper
limit of 0.03 percent to regular optical pulsations from HZ Her can be
understood if the time to convert X-ray energy to emitted optical light
is of the order of 10 seconds or longer. An upper limit of 3 percent is
derived for any rapid optical variability from the optical companions
of 2U 0900-40, 2U 1700-37, and Cyg X-1; the expected fluctuations
of optical light from HDE 226868 are less than 3 x 10- if the X-ray
variability of Cyg X-1 has a shot-noise character. Subject headings:
variable stars - X-ray sources
Title: Faint envelopes of galaxies.
Authors: Kormendy, J.; Bahcall, J. N.
Bibcode: 1974AJ.....79..671K
Altcode:
No abstract at ADS
Title: Multiple Star Systems and X-Ray Sources
Authors: Bahcall, J. N.; Dyson, F. J.; Katz, J. I.; Paczynski, B.
Bibcode: 1974ApJ...189L..17B
Altcode:
Two classes of triplestar models are proposed X-ray sources of the type
of Cygnus X-1 to be interpreted without invoking a black hole. The large
mass which is usually assigned to the X-ray source Cyg X-1 belongs in
the models to a normal star. Subject headings: binary stars - black
holes - stellar dynamics - X-ray sources
Title: Upper Limit on 2.5-SECOND Pulsations from Hercules X-1
Authors: Avni, Y.; Bahcall, J. N.; Joss, P. C.; Lamb, D. Q.; Schreier,
E.; Tananbaum, H.
Bibcode: 1974ApJ...188L..35A
Altcode:
No pulsed power is detected with a period of 2.5 seconds in the 1972
January Uhuru observations of Her X-1. An upper limit of 7 percent
is derived for the amount of 2.5-s pulsed modulation relative to the
observed amount of 1. pulsed modulation (corresponding to an upper limit
of 5 X 1(h for the ratio of signals in the power spectrum). Subject
headings: binaries - collapsed stars - neutron stars - pulsation -
X-ray sources
Title: Near Infrared Observations of Cygnus X-3
Authors: Bahcall, John N.
Bibcode: 1974Natur.247..446B
Altcode:
THE system known as Cygnus X-3 has been extensively studied at radio
wavelengths (where it exhibits extraordinary variability1-3),
in X rays (where it exhibits a 4.8 h period4-6),
and in the infrared at 1.6 and 2.2 µm (where it also displays
a 4.8 h period as well as large flares7,8). Attempts
have also been made to detect Cyg X-3 in visual and near infrared
wavelengths9,10. Here we present the results of a series of
observations made at near infrared wavelengths, λeffective
~=0.85 µm on ten nights in July and August 1973.
Title: Some properties of X-ray binaries.
Authors: Bahcall, J. N.
Bibcode: 1974ucyr.conf..343B
Altcode:
No abstract at ADS
Title: The redshift controversy. Papers from a symposium, Washington,
D.C., December 1972.
Authors: Field, G. B.; Arp, H.; Bahcall, J. N.
Bibcode: 1974rcpf.book.....F
Altcode:
No abstract at ADS
Title: Close Pairs of QSOs
Authors: Bahcall, John N.
Bibcode: 1974Natur.247...22B
Altcode:
IT has recently been argued1,2 that the observation of
close pairs of QSOs with very different redshifts provides support
for non-cosmological explanations of the redshifts. We show in this
note that the pairs observed so far may be comfortably explained as
random coincidences and that the small probabilities that are often
quoted depend on the use of a posteriori statistics.
Title: Optical properties of binary X-ray sources.
Authors: Bahcall, J. N.; Bahcall, N. A.
Bibcode: 1974asgr.proc...73B
Altcode:
The optical counterparts of six X-ray sources known to be in binary
systems are discussed (HZ Her/Her X-1, ?/Cen X-3, HD 153919/3U 1700-37,
HD 77581/Vela XR-1, Sk 160/SMC X-1, and HDE 226868/Cyg X-1). Detailed
summaries of data for each system are presented and include X-ray
and optical properties, establishment of optical identifications, and
mass estimates. Significant facts noted include the unusual spectral
type, optical luminosity and variations, and position of HZ Her;
the difficulty in determining the counterpart of Cen X-3; and the
substantial evidence that Cyg X-1 is a black hole. Attempts to locate
an optical counterpart to Cyg X-3 are described, and uncertainties
in determining the masses of X-ray sources with and without regular
pulsations are noted.
Title: A model for the light curve of HZ Herculis.
Authors: Joss, P. C.; Avni, Y.; Bahcall, J. N.
Bibcode: 1973ApJ...186..767J
Altcode:
The sharp minimum in the optical light curve of HZ Her is very different
from the flat-bottomed X-ray eclipse of Her X-1. A simple model is
presented which is consistent with the shapes of the minima of both the
optical and X-ray light curves and which quantitatively reproduces the
entire optical light curve (B-magnitudes). The essential feature of the
model is the assumption that some of the incoming radiation from Her
X-1 is absorbed well above the photosphere of HZ Her and is reradiated
locally as optical light. Some possible observational consequences of
this general class of models are discussed, including variations in
the flux and spectrum of the X-rays at the beginning and end of the
eclipse, optical emission lines, and UBV colors. Subject headings:
eclipsing binaries stars, individual X-ray sources
Title: Steady Energy Source in Her X-l?
Authors: Avni, Y.; Bahcall, J. N.; Joss, P. C.; Bahcall, N. A.; Lamb,
F. K.; Pethick, C. J.; Pines, D.
Bibcode: 1973NPhS..246...36A
Altcode: 1973Natur.246...36A
OBSERVATIONS of the Her X-l system show that the X-ray emission
above ~ 2 keV has three cycles : a pulsation period of 1.2 s; a 1.7-d
orbital period associated with the motion of Her X-l about HZ Her;
and a 35-d cycle during which the source is in a high, observable
state for some 12 d, followed by a 23-d low period during which no X
rays are observed1,2. Optical emission from HZ Her shows
periodic brightness changes with a 1.7-d period, such that the phase
of maximum brightness coincides with the maximum in the pulsed X-ray
intensity3,4. These observations have been interpreted in
terms of HZ Her as a late A or early F star which has a bright side
as a result of heating due to radiation from Her X-l (refs 3 to 7).
Title: Nuclear Fusion in Accreting Neutron Stars
Authors: Rosenbluth, M. N.; Ruderman, M.; Dyson, F.; Bahcall, J. N.;
Shaham, J.; Ostriker, J.
Bibcode: 1973ApJ...184..907R
Altcode:
We note that the total energy release from hydrogen accreting onto
a neutron star consists of two entirely distinct contributions: (1)
the gravitational potential energy loss by bringing additional mass
down to the stellar surface; (2) the energy released in the fusion
of the added hydrogen to form helium and heavier nuclei, about 7 MeV
per nucleon. The fusion energy source is sufficiently far below the
relatively opaque stellar surface that it heats the entire star and the
whole surface becomes an X-ray source considerably cooler than the more
localized source from contribution 1. These cooler X-rays may persist
for many years after accretion is interrupted. We suggest that these
notions could be relevant to some X-ray sources, perhaps even to the
optical X-ray binary in Hercules. Subject headings: neutron stars -
nuclear reactions - X-ray sources
Title: A Search for High-Excitation Redshift Systems in the Absorption
Spectra of Five Quasars
Authors: Bahcall, J. N.; Joss, P. C.; Cohen, J. G.
Bibcode: 1973ApJ...184...57B
Altcode:
We have searched the absorption spectra of five quasars for the presence
of redshift systems dominated by the highly ionized doublets C iv, N
v, and 0 vi, which could be the strongest lines produced by absorbing
clouds with collisional ionization temperatures between 10 and 106
K. There is at most marginal evidence for one such system apiece in the
spectra of PHL 957 and 4C 05.34, which are the two quasars with the
largest known emission redshifts. Highly ionized redshift systems of
this type are not widespread among the five quasars we investigated; the
number of redshifts found in the observed spectra is not significantly
larger than the number found in similar random-number spectra. Less
than 5 percent of the observed absorption lines are identified in a
statistically significant way by redshift systems of this type. Subject
headings: quasi-stellar sources or objects - redshifts
Title: Observations of QSOs in the direction of clusters of galaxies.
Authors: Bahcall, N. A.; Bahcall, J. N.; Schmidt, M.
Bibcode: 1973ApJ...183..777B
Altcode:
A search for QSOs in the direction of 66 Abell clusters of galaxies
has yielded eight objects with redshifts ranging from 0.09 to
2.06. Statistical arguments suggest that the ratio of bright QSOs to
bright galaxies in clusters of galaxies is not more than 10 times
that ratio in the field. The number of QSOs found is larger than
expected from field surveys, but the apparent excess may be caused
by systematic error in our magnitudes. Subject headings: galaxies,
clusters of - quasi-stellar sources or objects - redshifts
Title: Nonspherical Thermal Instabilities
Authors: Rosenbluth, Marshall N.; Bahcall, John N.
Bibcode: 1973ApJ...184....9R
Altcode:
General conditions for the existence of nonspherical thermal
instabilities are derived. The instabilities are not present in
numerical models of the Sun that have been tested. Subject headings:
instabilities - interiors, solar
Title: Radio Stars and X-ray Sources
Authors: Bahcall, John N.; Kellogg, Edwin M.
Bibcode: 1973NPhS..244..135B
Altcode: 1973Natur.244..135B
SEVERAL weak, highly variable radio sources have been shown by excellent
optical-radio positional agreement (~ 1 arc s) to be associated with
optically bright binary stars1-13. One of these radio stars,
associated with the optical binary HDE-226868 (refs 10-16) has been
suggested as the optical-radio counterpart of the strong variable
X-ray source, Cyg X-1 (a frequently discussed candidate for a black
hole). We report limits on the X-ray emission from the known radio
stars that can be studied with Uhuru. These results are of interest
because of the possible association between X-ray binaries and radio
star binaries, and because limits or measurements of the X-ray fluxes
can help determine the source of the radio emission. A strong limit
(comparable to those reported here) on the X-ray emission from the
optical-binary β Persei during periods of radio flaring has recently
been reported by the MIT OSO-7 group17.
Title: Solar Neutrinos.IV. Effect of Radiative Opacities on Calculated
Neutrino Fluxes
Authors: Bahcall, John N.; Huebner, W. F.; Magee, N. H., Jr.; Merts,
A. L.; Ulrich, Roger K.
Bibcode: 1973ApJ...184....1B
Altcode:
The effect of radiative opacities on the predicted capture rate for
the 37Cl solar neutrino experiment is investigated with the aid of new
opacities obtained from an improved Los Alamos code. Subject headings:
interiors, solar - neutrinos - opacities
Title: On the Temperature of the Microwave Background Radiation at
a Large Redshift
Authors: Bahcall, John N.; Joss, Paul C.; Lynds, Roger
Bibcode: 1973ApJ...182L..95B
Altcode:
It is shown that the temperature of the microwave background radiation
at a redshift of the order of 2.5 is certainly less than 200 K and
probably less than 45 K. Further detailed studies of the absorption
spectra of large-redshift quasars can improve these limits. Subject
headings: cosmic background radiation - quasi-stellar sources or objects
Title: Model for X-ray Sources Based on Magnetic Field Twisting
Authors: Bahcall, John N.; Rosenbluth, Marshall N.; Kulsrud, Russell M.
Bibcode: 1973NPhS..243...27B
Altcode: 1973Natur.243...27B
SEVERAL X-ray sources have been identified with binary stellar
systems. It has been generally concluded that the presence of X-rays
implies one of the stars must be a collapsed object (white dwarf,
neutron star or black hole) which accretes matter from the other star,
thus producing the X-rays. To a certain extent, this conclusion is
based on the absence at present of any reasonable alternative model
for the origin of X-rays. Because of the importance of establishing
whether binary X-ray sources contain collapsed objects, we feel that
it is worthwhile to attempt to construct alternative models and to
derive their observational properties.
Title: Optical and Near-Infrared Observations of the Nearby Spiral
Galaxy Maffei 2
Authors: Spinrad, Hyron; Bahcall, J.; Becklin, E. E.; Gunn, James E.;
Kristian, J.; Neugebauer, G.; Sargent, W. L. W.; Smith, H.
Bibcode: 1973ApJ...180..351S
Altcode:
Spectra, photographs, and photometric measurements have been
used to show that Maffei 2 has a distance of 5 i 2 Mpc and that
it has a morphological type near Sbc II in agreement with similar
conclusions made earlier by radio observers. We discuss the possible
relationships between Maffei 2 and the elliptical galaxy Maffei 1;
there are serious inconsistencies in the existing data which bear on
this question. Subject headings: galaxies, individual - infrared sources
Title: The Hubble Diagram for the Brightest Quasars
Authors: Bahcall, John N.; Hills, Richard E.
Bibcode: 1973ApJ...179..699B
Altcode:
The slope of the magnitude-redshift relation for the optically most
luminous quasars with redshifts ranging from 0.2 to more than 2 is
consistent with the value of 5 expected from the expansion of the
universe if luminosities are evaluated assuming quasars are at the
cosmological distances implied by their redshifts. Subject headings:
cosmology - quasi-stellar sources or objects - redshifts - relativity
Title: An analysis of the absorption spectrum of PHL 957.
Authors: Bahcall, J. N.; Joss, P. C.
Bibcode: 1973ApJ...179..381B
Altcode:
Five absorption redshifts ranging from z = 2.67 to z = 2.22 are
identified in the observed spectrum of PHL 957, in good agreement
with the earlier analysis of Lowrance et al. Our results are to be
compared with an average of 1.0 i 0.9 redshifts found in random-number
spectra having the same essential characteristics as the observed
spectrum. The distribution of identified absorption redshifts is
presented and discussed for five quasars, whose rich absorption
spectra have all been studied with the same methods as those used in
the present investigation. Subject headings: line identifications -
quasi-stellar sources or objects - redshifts
Title: The Hubble Diagram for the Brightest Quasars
Authors: Hills, Richard E.; Bahcall, John N.
Bibcode: 1973NYASA.224...58H
Altcode:
No abstract at ADS
Title: Quasar Variability as a Function of Absolute Luminosity
Authors: Ames, Susan; Bahcall, John N.
Bibcode: 1973ApL....14..199A
Altcode:
No abstract at ADS
Title: The redshift controversy
Authors: Field, George B.; Arp, Halton C.; Bahcall, John N.
Bibcode: 1973reco.book.....F
Altcode: 1973QB465.F53......
No abstract at ADS
Title: HZ Herculis.
Authors: Goldsmith, S.; Bahcall, J. N.; Bahcall, N. A.
Bibcode: 1973IAUC.2529....1G
Altcode:
No abstract at ADS
Title: The solar neutrino problem.
Authors: Bahcall, J. N.
Bibcode: 1973NucIM..11..381B
Altcode:
No abstract at ADS
Title: Redshifts as distance indicators.
Authors: Bahcall, J. N.; Arp, H.
Bibcode: 1973reco.conf...61B
Altcode:
No abstract at ADS
Title: On the Luminosity Functions of Giant Stars in Globular Clusters
Authors: Bahcall, John N.; Yahil, Amos
Bibcode: 1972ApJ...177..647B
Altcode:
The observed luminosity function for stars on the giant branch of
M15, as determined by Sandage, Katem, and Kristian, is compared with
simulated luminosity functions generated from a smooth curve. Apparent
features are seen in both the observed and simulated luminosity
functions. A crude fit to the observed differential luminosity function
is given by N(L) cc L -26
Title: The Period and Light Curve of HZ Herculis
Authors: Bahcall, John N.; Bahcall, Neta A.
Bibcode: 1972ApJ...178L...1B
Altcode:
It is shown that HZ Hercutis has an eclipse period and phase equal to
the eclipse period and phase of the pulsating X-ray source Hercules
X-1. Data for HZ Hercutis are also given for the light curve, colors,
proper motIon, and the influence of the 35 day X-ray cycle on the
optical light. A model for the binary system is described and the
optical light curve is calculated.
Title: The Estimation of Masses of Individual Galaxies in Clusters
of Galaxies
Authors: Wolf, Richard A.; Bahcall, John N.
Bibcode: 1972ApJ...176..559W
Altcode:
Expressions are derived for approximate limits on the mass of an
individual galaxy or quasi-stellar object that is a member of a group
or cluster of galaxies. Two different approaches are used: first, a
perturbation method that yields approximate limits on the mass of any
observed object in a cluster provided only that the positions of cluster
galaxies around the unknown mass are measured and redshifts are known
for several galaxies in the cluster; and second, an extension of Page's
method that gives approximate mass limits for any bound pair of galaxies
whose positions and redshifts are known. The uncertainties in the mass
estimates, arising from both observational and statistical effects,
are estimated analytically. An "upper estimate," 80 percent certain
to be greater than the actual mass of the galaxy, can be obtained in
every case. A "best guess," at least 50 percent certain to be greater
than the actual mass of the galaxy, and a "lower estimate," 80 percent
certain to be less than the actual galaxy mass, can be obtained in
some cases. The analytically derived formulae for the upper, lower,
and best-guess estimates are then verified by comparison with computer
simulatinas of the dynamical evolution of clusters of galaxies, using
the numerical methods of Aarseth. Estimates are made of the masses
of NGC 6166 ( 3C 338), NGC 4874 and 4889 (the giant ellipticals near
the center of the Coma cluster), B264, TON 256, PKS 2251+11, and 10
supergiant galaxies that have double nuclei. We obtain the following:
for NGC 6166, 8 X 1011 M0 <M <4 X 10' M0 and 8 < AI/L <400 g
s for NGC 4874, Al <= 2 X 1014 Al0 and M/L <2000g s erg-1 for NGC
4889, Al <3 X 1014 Al0 and Al/L < 2100 g s for B264, Al < 7 X
tOll Al0 and Al/L < 3000 g s 256, Al < 4 X 1011 Al0 and Al/L <
300 g s and for PKS 2251+11, Al < 3 X 1013 Al0 and Al/L < 40 g s .
Title: On Identifying New Kinds of Astronomical Objects
Authors: Bahcall, John N.; Yahil, Amos
Bibcode: 1972NPhS..238...92B
Altcode: 1972Natur.238...92B
WE wish to draw attention to a statistical problem that arises in an
especially acute form when the data from a number of new sources are
analysed to try to find evidence for a particular kind of object, for
example, a neutron star or a black hole. We wish to emphasize that a
statistical analysis of the data on any particular source must include
consideration of the data on other sources that were found.
Title: Are Galaxies Formed by Material Flowing Out of Singularities?
Authors: Bahcall, J. N.; Joss, P. C.
Bibcode: 1972CoASP...4...95B
Altcode: 1972ComAp...4...95B
No abstract at ADS
Title: Quarks as a Thermometer for Cosmologies
Authors: Frautschi, Steven; Steigman, Gary; Bahcall, John
Bibcode: 1972ApJ...175..307F
Altcode:
If physical quarks exist, their density relative to ordinary baryons
(nq/flB) depends sensitively on the highest temperatures reached
during cosmological evolution. Zel'dovich has pointed out that in
the conventional hot big bang with a limited spectrum of elementary
particles the quark density flq/flB predicted for the present time is
much larger than the experimental upper bound. In the present paper we
derive the consequences for conventional cosmologies of the Hagedorn
type of hadron spectrum which implies a "warm" limiting temperature of
order kT 160 MeV. With initial temperatures of this order, the predicted
flq/flB is consistent with present experimental limits if the quark
mass exceeds 9 GeV. In the Hagedorn model, quarks with rn, > 9 GeV
would be very difficult to produce in accelerator experiments because of
statistical competition; searches for fossil quarks in bulk matter seem
to offer the only hope of detection. We also discuss predictions for
the quark density in several less conventional cosmologies (mix master,
Brans-Dicke, Lemaitre, steady state, and Klein-Alfven) and with forms of
the hadron density of states that differ from Hagedorn's proposed form
Title: Some Observational Distinctions Among Models of Pulsing
X-Ray Binaries
Authors: Arons, J.; Bahcall, J. N.
Bibcode: 1972ApL....11..191A
Altcode:
No abstract at ADS
Title: Galaxy Distributions in the Zwicky Catalogue.
Authors: Hauser, M. G.; Bahcall, J. N.
Bibcode: 1972BAAS....4R.239H
Altcode:
No abstract at ADS
Title: Models for the Cosmic Evolution of Radio Galaxies and Quasars.
Authors: Bahcall, John N.
Bibcode: 1972ApJ...172..265B
Altcode:
The observational distinctions between various explanations
of radio-source evolution are exhibited with the aid of simple
models. These models are derived by using a formalism that enables one
to calculate, on the basis of explicit hypotheses, the number of sources
that are present at a given cosmic time. Particular attention is given
to "ultraconservative" and "symmetric" models. In the ultraconservative
models, the total number of galaxies that have been radio galaxies is
constant in time (after some creation period), but most of what are
today "normal" galaxies were powerful radio sources when they were
younger. In the symmetric models, the evolution of radio galaxies
and quasars is treated in the same way by using coupled equations
that suggest a mean life for the primordial bright ellipticals of 10
years. Both the ultraconservative and the symmetric models suggest that
there may be significant departures from the usually predicted relations
in the diagram of apparent magnitude versus redshift for largeredshift
radio galaxies because the usual relations are calculated for objects
with typical luminosities that are independent of cosmic time. The
observational basis for some of the evolutionary models considered is
strengthened by the application of the luminosity-volume test to an
essentially complete sample of 3C R radio galaxies for which redshifts
and accurate optical magnitudes are available. The results confirm and
strengthen the conclusions of revious investigators regarding the lack
of evolution among radio galaxies with an intrinsic power at 1 8 MHx
of less than 1026 V .
Title: On the Time Dependence of Emission-Line Strengths from a
Photoionized Nebula
Authors: Bahcall, John N.; Kozlovsky, Ben-Zion; Salpeter, E. E.
Bibcode: 1972ApJ...171..467B
Altcode:
Discussions are given for the time dependence of emission-line
intensities from nebulae that are photoionized by a central source
with a variable continuum flux. Explicit calculations are carried
out for some cases (especially when the nebula can be considered
a thin shell) for a temporary increase of continuum flux of simple
"square-wave hump" shape. In some cases, changes in line intensities
are predicted over times that are small compared with the light travel
time across the nebula. The observational situation is described and
further measurements are suggested for a number of objects that are
relatively easy to study and whose further investigations seem likely to
lead to important conclusions regarding the nebular parameters. These
promising objects include QSOs, and N-type, Seyfert, and compact
galaxies, as well as some X-ray sources and old novae.
Title: Are Quasars Associated with Bright Galaxies?
Authors: Bahcall, J. N., Mckee, C. F.; Bahcall, N. A.
Bibcode: 1972ApL....10..147B
Altcode:
No abstract at ADS
Title: HZ Herculis.
Authors: Bahcall, J. N.; Bahcall, N. A.; Crampton, D.; Morbey, C. L.
Bibcode: 1972IAUC.2428....1B
Altcode:
No abstract at ADS
Title: The solar neutrino problem.
Authors: Bahcall, J. N.
Bibcode: 1972CNPPh...5...59B
Altcode:
No abstract at ADS
Title: Solar Neutrinos
Authors: Bahcall, John N.; Sears, R. L.
Bibcode: 1972ARA&A..10...25B
Altcode:
No abstract at ADS
Title: Are Neutrinos Stable Particles?
Authors: Bahcall, John N.; Cabibbo, Nicola; Yahil, Amos
Bibcode: 1972PhRvL..28..316B
Altcode:
It is pointed out that neutrinos with a finite mass could be
unstable. We discuss the consequences of this possibility for
solar-neutrino experiments.
Title: HZ Herculis.
Authors: Bahcall, J. N.; Bahcall, N. A.; Liller, W.; Jones, C.;
Forman, W.; Shao, C. Y.
Bibcode: 1972IAUC.2427....1B
Altcode:
No abstract at ADS
Title: The Hadron Barrier in Cosmology and Gravitational Collapse
Authors: Bahcall, John N.; Frautschi, Steven
Bibcode: 1971ApJ...170L..81B
Altcode:
It is shown that the early stages of a big-bang cosmology are
hadron-dominated if the density of hadron states per unit mass
interval, p (m), increases at least as fast as m ' and if the initial
gravitational anisotropy is not large. It is further shown that if these
conditions are satisfied, then quantum effects must modify the classical
equations of general relativity at times t 1(t23 5 before the attainment
of the singularities predicted in classical relativistic cosmologies
and stellar collapse (i.e., before the well- known modifications due
to quantum fluctuations of the metric at times l0- s).
Title: Solar Neutrinos. III. Composition and Magnetic-Field Effects
and Related Inferences
Authors: Bahcall, John N.; Ulrich, Roger K.
Bibcode: 1971ApJ...170..593B
Altcode:
An improved solar model is shown to yield a calculated capture rate
for the 27CI neutrino experiment that is a factor of 6 larger than the
observed rate reported by Davis, Rogers, and Radeha. The 5B branch
must occur a factor of 10 less often than expected on the basis of
standard solar models. The effects on the calculated capture rates of
a variety of composition uncertainties are considered. The effects of
a strong primordial magnetic field are also investigated. The results
obtained by several investigators who used different stellar-evolution
programs are compared, and it is concluded that the different programs
give consistent, but observationally incorrect, results.
Title: On the Absorption-Line Spectrum of 4c 05.34
Authors: Bahcall, John N.; Goldsmith, Samuel
Bibcode: 1971ApJ...170...17B
Altcode:
Eight acceptable absorption redshifts are found in the spectrum of
4C 05.34 reported by Lynds. The absorption redshifts range from z =
2.875 to z = 1.776. An average nonsense spectrum has 1.4 acceptable
redshifts. The absence of absorption from excited fine-structure states
implies that the absorbing region has an electron density <102 and
is at a distance >1 kpc from the continuum source of the QSO.
Title: Ultradense Matter
Authors: Frautschi, S.; Bahcall, J. N.; Steigman, G.; Wheeler, J. C.
Bibcode: 1971CoASP...3..121F
Altcode: 1971ComAp...3..121F
No abstract at ADS
Title: Relative Correlation of - and Small-Redshift Quasi-Stellar
Objects with Clusters of Galaxies
Authors: Bahcall, John N.; Bahcall, Neta A.; Burbidge, G. R.
Bibcode: 1971ApJ...166L..77B
Altcode:
The importance of investigating the relative probability that large-
and small-redshift QS0s appear in the direction of catalogued clusters
of galaxies is discussed. This relative probability is determined for
a large sample of QS0s with respect to both Zwicky and Abell clusters
of galaxies. The results are summarized in three general conclusions.
Title: The Ionization Structure of a Nebula Photoionized by a Flat
Spectrum
Authors: Bahcall, J. N.; Bahcall, N. A.; Kozlovsky, B. -Z.
Bibcode: 1971A&A....13....1B
Altcode:
Analytic approximations are developed in this paper for the ionization
structure of a medium that is photoionized by a flat spectrum. The
presence of a diffuse ionization zone depends on the precise form of the
ultraviolet ionization spectrum. For a photon number spectrum that falls
off as -1 there is a diffuse ionization structure and for a spectrum
that falls off like v- there is a more classical Stro. mgren-like
behavior with a halfwidth an order of magnitude smaller than in the v-1
case. The basic equations are also presented for a more general class of
spectral indices as well as a power law behavior of the total density
on distance from the ionization source. Key words: photoionization -
flat spectrum - Seyfert galaxies - quasars - spectral index.
Title: Some Unsolved Problems in Astrophysics
Authors: Bahcall, John N.
Bibcode: 1971AJ.....76..283B
Altcode:
The theoretical and observational situation with regard to solar
neutrinos is reviewed and some of the implications of the discrepancy
between theory and observation are discussed. A definition is suggested
for compact luminous objects (CLO's) and various proposals for the
energy source of CLO's are reviewed. The observational situation and
opportunities with regard to the association of CLO's (or QSO's) with
galaxies is outlined. The absorption lines observed in large-redshift
CLO's are divided tentatively into two classes whose origin is
discussed. A number of critical observations are suggested to test
various unorthodox ideas.
Title: Upper Limit on Neutrino Energy Associated with Weber Pulses
Authors: Bahcall, John N.; Davis, Raymond
Bibcode: 1971PhRvL..26..662B
Altcode:
An upper limit is established on the fraction of energy associated
with the gravitational pulses reported by Weber that could be in the
form of neutrinos with energies between 0.9 and 100 MeV.
Title: Quark Fusion in Quasi-Stellar Objects?
Authors: Bahcall, John N.; Callan, C. G., Jr.; Dashen, Roger
Bibcode: 1971ApJ...163..239B
Altcode:
The rates of the most likely quark-fusion reactions are estimated. An
approximate formula is derived for the efficiency (>50 percent)
of converting rest mass into photons by quark fusion. The temperature
at which quarks might fuse is crudely estimated to be a few million
degrees Kelvin. Several ways are discussed that quark-electron atoms
could conceivably be detected in astronomical objects.
Title: Some Inferences from Spectrophotometry of Quasi-Stellar Sources
Authors: Bahcall, John N.; Oke, J. B.
Bibcode: 1971ApJ...163..235B
Altcode:
Limits are placed on the amount of neutral and ionized hydrogen gas
that can be in the vicinity of 4C OS 34 (and three other QSSs); these
results place severe restraints on models of quasi-stellar radio sources
in which the QSS phenomenon is supposed to occur within a galaxy A
limit on the electron temperature is also established (1 x 10 <
< 2 X 10 K) The relative abundance of C++ to C+++ is determined
approximately in five QSSs, and the ratio of helium to hydrogen is
estimated for fourteen QSSs.
Title: Solar Neutrinos
Authors: Bahcall, J. N.
Bibcode: 1971AIPC....2..243B
Altcode:
No abstract at ADS
Title: Extragalactic Pulsars
Authors: Bahcall, John N.; Rees, Martin J.; Salpeter, E. E.
Bibcode: 1970ApJ...162..737B
Altcode:
Newly formed pulsars might be detectable out to distances 10 Mpc by
searching for millisecond optical or X-ray pulses from the sites of
newly reported supernovae.
Title: On the Bowen Resonance Fluorescence Lines in Quasi-Stellar
Objects
Authors: Bahcall, John N.; Kozlovsky, Ben-Zion
Bibcode: 1970ApJ...162..789B
Altcode:
It is shown that the Bowen resonance fluorescence lines are expected
to be weak in QSOs even if the nebula is photoionized.
Title: Galaxies in the Direction of QSO's With Small Redshifts
Authors: Bahcall, Neta A.; Bahcall, John N.
Bibcode: 1970PASP...82.1276B
Altcode:
Accurate positions are given for the brightest galaxies that are likely
to be associated with all known QSO's with redshifts less than or equal
to 0.2. Special attention is drawn to the galaxies in the direction of
3C 273. It is shown that the probabili is small that purely by chance
coincidence a galaxy redshift will be measure to be approximately
equal to that of a quasar in its direction.
Title: Comet Gunn (1970p)
Authors: Schmidt, M.; Gunn, J. E.; Bahcall, J. N.; Young, J. W.;
Marsden, B. G.
Bibcode: 1970IAUC.2294....1S
Altcode:
Dr. M. Schmidt, California Institute of Technology, reports that a
comet was discovered by James E. Gunn on a plate exposed with the
122-cm Schmidt telescope at Palomar on October 27. From the trailed
image the daily motion was determined as dR.A. = -0m71, dDecl. =
-2'. Further images of the comet were located on plates exposed with
the same telescope on November 22 and 23 by J. N. Bahcall. The comet was
diffuse, with central condensation and a small tail. Dr. Gunn measured
accurate positions from the three plates, as shown below. The comet
was also recorded on November 6 by J. W. Young on three plates exposed
with the 61-cm reflector at Table Mountain Observatory, Wrightwood,
California. 1970 UT R.A. (1950) Decl. m1 Observer Oct. 27.22500 1
23 41.6 - 2 01 45 16 Gunn Nov. 6.31250 1 17 11.7 - 2 14 03 15 Young
6.34722 1 17 09.9 - 2 13 56 " 22.27014 1 09 29.5 - 2 10 00 16 Bahcall
23.30486 1 09 08.3 - 2 08 48 16 " The elliptical elements below, by
the undersigned, are very uncertain, but the ephemeris should help
observers to locate the comet. Differential residuals of 8" and 11"
remain between the second and third, and the fourth and fifth positions,
respectively. T = 1969 Mar. 14.47 ET Peri. = 195.70 e = 0.2931 Node =
66.91 1950.0 a = 3.5599 AU Incl. = 10.62 n = 0.14674 q = 2.5164 AU P =
6.72 years 1970/71 R. A. (1950) Decl. Delta r m1 Dec. 10 1 05.75 - 1
32.4 20 1 05.97 - 0 57.7 3.518 3.925 16.7 30 1 07.78 - 0 15.0 Jan. 9
1 11.05 + 0 34.5 3.866 3.969 16.9 19 1 15.61 + 1 29.4 29 1 21.30 +
2 28.4 4.212 4.013 17.2 m1 = 8.0 + 5 log Delta + 10 log r
Title: Multiple Absorption Redshifts in Quasars
Authors: Bahcall, J. N.
Bibcode: 1970CoASP...2..221B
Altcode: 1970ComAp...2..221B
No abstract at ADS
Title: Photon Splitting in a Strong Magnetic Field
Authors: Adler, S. L.; Bahcall, J. N.; Callan, C. G.; Rosenbluth, M. N.
Bibcode: 1970PhRvL..25.1061A
Altcode:
We determine the absorption coefficient and polarization selection
rules for photon splitting in a strong magnetic field, and describe
the possible application of our results to pulsars.
Title: On the Rich Absorption Spectra of Three Quasi-Stellar Objects
Authors: Bahcall, John N.; Feldman, Uri
Bibcode: 1970ApJ...161..389B
Altcode:
The absorption spectra of PHL 938, TON 1530, and PKS 0237-23 have
been searched in a systematic way for redshifts that may include lines
arising from metastable states, interstellar lines, and Balmer lines. A
search for blueshifts was also carried out for the first time. The
statistical significance of the redshift system I = 0.6128 in PIlL
938 was established by analyzing random-number spectra. It is shown
that the electron density is less than 50 T4112 in the vicinity of
this absorption system and that the minimum separation between PHL 938
and the absorption system is about 100 pc. A critical test of the idea
that normal galaxies produce the absorption lines is described. Nine
interstellar lines observed in the spectra of stars in the galaxy might
appear in the.observationally accessible region between 4956 and 6400
A for the redshift system I = 0.6128 of PHL 938.
Title: On the Galaxies in the Direction of Ton 256 and B 264
Authors: Bahcall, John N.; Bahcall, Neta A.
Bibcode: 1970PASP...82..721B
Altcode:
No abstract at ADS
Title: Solar-Neutrino Fluxes with Recent Corrections to Opacity
Authors: Bahcall, John N.; Ulrich, Roger K.
Bibcode: 1970ApJ...160L..57B
Altcode:
Improved calculations of the rate of solar-neutrino capture for
experiments with 87Cl and 7Li are presented. There is a sizable
discrepancy between the calculated values and the experimental upper
limit of Davis et at. The primordial helium abundance inferred from the
relevant solar models ranges from Y = 0.22 to Y = 0.26. The expected
neutrino capture rates in the 87Cl and 7Li experiments and the inferred
primordial helium abundance are sensitive to the presentday photospheric
abundance ratio of iron to hydrogen.
Title: Upper Limits on the Masses of Quasi-Stellar Sources
Authors: Bahcall, John N.; Salpeter, E. E.
Bibcode: 1970ApJ...159L.135B
Altcode:
No abstract at ADS
Title: Some Models for the Emission-Line Region of 3c 48
Authors: Bahcall, John N.; Kozlovsky, Ben-Zion
Bibcode: 1969ApJ...158..529B
Altcode:
Models for the emission-line region of 3C 48 are derived by using
calculated ionization distributions. Estimates are given of the
parameters that characterize the emission-line region and of the
relative abun- dance of H, He, 0, Ne, and Mg
Title: Quasi-Stellar Objects in the Direction of Rich Clusters
of Galaxies
Authors: Bahcall, John N.
Bibcode: 1969ApJ...158L..87B
Altcode:
Fourteen quasi-stellar objects are listed that are in the direction of
rich clusters of galaxies in Abell's catalog. The importance of making
redshift measurements of galaxies with small angular separations from
quasi-stellar objects with redshifts <0.2 is discussed
Title: On the Masses of Quasi-Stellar Sources
Authors: Bahcall, John N.; Salpeter, E. E.
Bibcode: 1969ApJ...158L..15B
Altcode:
No abstract at ADS
Title: Quasi-Stellar Objects in the Direction of Clusters of Galaxies
Authors: Bahcall, John N.
Bibcode: 1969ApJ...157L.151B
Altcode:
Twenty-one quasi-stellar objects are listed that are in the direction
of clusters of galaxies. These objects are interesting candidates for
absorption experiments
Title: Review Paper: Solar Neutrinos.
Authors: Davis, Raymond, Jr.; Bahcall, John N.
Bibcode: 1969BAAS....1Q.339D
Altcode:
No abstract at ADS
Title: On the Possibility of Detecting Redshifted 21-CM Absorption
Lines in the Spectra of Quasi-Stellar Sources
Authors: Bahcall, John N.; Ekers, Ronald D.
Bibcode: 1969ApJ...157.1055B
Altcode:
The expected strengths of redshifted 21-cm absorption lines are
estimated by using the properties of the observed optical absorption
lines in quasi-stellar sources. It is shown that the absence of 0 i
and N i absorption lines in the observed optical absorption spectra of
quasi-stellar radio sources indicates that 21-cm absorption lines wider
than 100 kllz are likely to be weak unless the heavy-element abundance
in the absorbing material is low. Lines narrower than 100 kETz may be
strong; their optical counterparts would have escaped detection. A
general expression is given for the spin temperature of neutral
hydrogen when (following Field) Ly a excitation and de-excitation, 21-cm
absorption and emission, and particle collisions are all included. The
results are expressed simply in terms of the strength and distance of
the radio source and the separation between absorber and emitter. It
is shown that the spin temperature of neutral hydrogen is large near
a quasi-stellar radio source and is determined either by the ambient
21-cm flux or the ambient Ly a flux for separations between absorber
and emitter of less than about 1O~ It-yr. The expected absorption
(and emission) strengths of redshifted 21-cm lines are compared with
observa- tional capabilities at radio observatories. Some interesting
candidates for study are listed
Title: Are Some Quasi-Stellar Objects Associated with Clusters
of Galaxies?
Authors: Bahcall, John N.; Schmidt, Maarten; Gunn, James E.
Bibcode: 1969ApJ...157L..77B
Altcode:
Five small-redshift quasi-stellar objects are listed that are within
the approximate geometrica] boundaries of catalogued clusters of
galaxies. Spectra of four galaxies in one of the clusters show the
same redshift as the associated quasi-stellar object B264
Title: What Next with Solar Neutrinos?
Authors: Bahcall, John N.
Bibcode: 1969PhRvL..23..251B
Altcode:
The capture rate of solar neutrinos is estimated for a number of targets
that have been suggested previously as possible detectors of solar
neutrinos. It is shown that the most important feasible experiment to
be carried out in the future employs 7Li as a detector.
Title: Neutrinos from the Sun
Authors: Bahcall, John N.
Bibcode: 1969SciAm.221a..28B
Altcode: 1969SciAm.221...29B
No abstract at ADS
Title: Solar Neutrinos
Authors: Bahcall, John N.; Bahcall, Neta A.; Ulrich, Roger K.
Bibcode: 1969BAAS....1Q.272B
Altcode:
No abstract at ADS
Title: Sensitivity of the Solar-Neutrino Fluxes
Authors: Bahcall, John N.; Bahcall, Neta A.; Ulrich, Roger K.
Bibcode: 1969ApJ...156..559B
Altcode:
The sensitivity of the solar-neutrino fluxes to localized changes in
the opacity and the equation of state is calculated. The sensitivity
to changes in the equation of state reaches a maximum near 8 X 106
°K and is in general much larger than the sensitivity to opacity
changes. The effect of various parameters on the predicted rate of
neutrino capture in the 37C1 experiment is summarized in equation
(8). The char- acteristic numerical properties of a standard solar
model are then presented. Several general conclusions are justified on
the basis of the variations considered. In particular, an assessment
is given of the relation between the theory of solar models and the
experimental results of Davis, Harmer, and Hoffman
Title: Absorption Lines Produced by Galactic Halos
Authors: Bahcall, John N.; Spitzer, Lyman, Jr.
Bibcode: 1969ApJ...156L..63B
Altcode:
We propose that most of the absorption lines observed in quasi-stellar
sources with multiple absorp- tion redshifts are caused by gas in
extended halos of normal galaxies
Title: ON the Absorption Spectrum of Ton 1530
Authors: Bahcall, John N.; Osmer, Patrick S.; Schmidt, Maarten
Bibcode: 1969ApJ...156L...1B
Altcode:
An analysis of the absorption-line spectrum of Ton 1530 is reported. The
line widths are less than 4 A in the observed frame. Three acceptable
absorption redshifts, z = 1.9365, z = 1.9215, and z = 1.8866, and one
plausible absorption redshift, z = 1.9800, are identified. Only 0.1
acceptable redshift was found per random-number spectrum constructed
to have the same essential characteristics as the observed spectrum
Title: Statistical Tests for the Origin of Absorption Lines Observed
in Quasi-Stellar Sources
Authors: Bahcall, John N.; Peebles, P. J. E.
Bibcode: 1969ApJ...156L...7B
Altcode:
Two statistical tests are described for the hypothesis that the
multiple absorption redshifts observed in the spectra of at least some
quasi-stellar sources arise in intervening material that is randomly
distrib- uted in patches along the line of sight between us and the
quasi-stellar sources
Title: Some Models of the Emission-Line Region of 3c 273
Authors: Bahcall, John N.; Kozlovsky, Ben-Zion
Bibcode: 1969ApJ...155.1077B
Altcode:
Models for the emission-line region of 3C 273 are derived by using
ionization distributions calculated with extrapolated forms of the
observed photon flux. The calculated ionization distributions, which
are different from those assumed by previous workers, are used to
make estimates of the relative abundances of H, He, 0, Ne, Mg, and Fe
Estimates are also given of the physical parameters that characterize
the emission-line region
Title: The ^{7}Be Electron-Capture Rate
Authors: Bahcall, John N.; Moeller, Charles P.
Bibcode: 1969ApJ...155..511B
Altcode:
The effect of plasma and bound-electron screening on the continuum
capture rate of 7Be(e,~)7Li is calculated and shown to be negligible
for situations in which the proton-proton chain is likely to be im-
portant. A more accurate expression for the continuum capture rate
is then derived, making use of the numerical work of Bahcall and
May. Convenient formulae are presented for use in stellar-model calcula-
tions. The average effect of bound-electron capture is also evaluated
for several solar models
Title: Fine-Structure Transitions and the Background Microwave
Radiation
Authors: Petrosian, Vahé; Bahcall, John N.; Salpeter, E. E.
Bibcode: 1969ApJ...155L..57P
Altcode:
The contribution to the background microwave radiation from decays
of excited fine-structure states of the more abundant ions is
calculated. Transitions occurring in the Galaxy, in distant galaxies,
and in the intergalactic medium are considered. It is shown that the
intensity of radiation from fine-structure transitions in the Galaxy
and in nearby galaxies exceeds the intensity of a 2.7° K black body
for wave- lengths less than 0.05 cm
Title: The Rate of the Proton-Proton Reaction and Some Related
Reactions
Authors: Bahcall, John N.; May, Robert M.
Bibcode: 1969ApJ...155..501B
Altcode:
The results of detailed calculations of the rate of the proton-proton
reaction, p + p -~ 2D + e+ + v, and the related electron-capture
reaction, P + e + P -~ 2D + v, are presented. Estimates of the likely
errors are given. The rates of some other electron-capture reactions
that are of interest in connection with solar-neutrino experiments
are also calculated
Title: The Effect of the Brans-Dicke Cosmology on Solar Evolution
and Neutrino Fluxes
Authors: Shaviv, G.; Bahcall, J. N.
Bibcode: 1969ApJ...155..135S
Altcode:
The effect of the Brans-Dicke theory of gravitation on the evolution
of the Sun and the solar neu- trino flux is investigated Our results,
for fashionable values of the scalar field coupling constant, the Hubble
constant, and the heavy-element abundance, are (1) the solar luminosity
decreased by about 10-50 per cent during the last 4 7 billion years; and
(2) the solar neutrino flux for the Brans-Dicke theory is greater than
the corresponding flux for constant-G theories by a factor of about 2
Title: Observational Neutrino Astronomy: A ν-Review
Authors: Bahcall, John N.
Bibcode: 1969tsra.conf..321B
Altcode: 1969qhea.conf..321B
No abstract at ADS
Title: The Absorption-Line Spectrum of the Quasi-Stellar Radio Source
PKS 0237-23
Authors: Bahcall, John N.; Greenstein, Jesse L.; Sargent, Wallace L. W.
Bibcode: 1968ApJ...153..689B
Altcode:
We present in Table 2 the wavelengths of 49 absorption lines measured in
the wavelength range XX3300-4800 in the spectrum of the quasi-stellar
radio source PKS 0237- 23. Equivalent widths, half- widths, and
central depths are given for thirty-eight of these lines having X>
3650 A. A systematic proce- dure has been used by Bahcall (1968) to
identify twenty-eight of the lines with five absorption redshifts,
namely, z = 2.2015, 1.6706, 1.6560, 1.5132, and 1.3642. There is
no strong evidence for an absorption redshift of z = 1.95, found
by earlier workers. It is presumed that the absorption lines in PKS
0237-23 arise either in intergalactic space or in clouds which are near
the object and moving at speeds of up to 0 3 c relative to the source
of the emission lines. At present there is no compelling argument or
observation to distinguish between these two hypotheses
Title: A Systematic Method for Identifying Absorption Lines as
Applied to PKS 0237-23
Authors: Bahcall, John N.
Bibcode: 1968ApJ...153..679B
Altcode:
A systematic method for identifying the absorption lines in
quasi-stellar sources with rich absorption spectra is described, and
the lines that are expected on theoretical grounds to have the highest
probability of appearing in absorption in quasi-stellar sources are
listed. The computational scheme that was devel- oped for recognizing
and analyzing candidate redshifts is then described; this computationa'
scheme is supplemented by a set of rules used to determine if a
candidate redshift is acceptable The computational scheme and formal
rules were applied to a set of nonsense spectra, i.e, random-number
spectra, with the same main characteristics as the absorption spectrum
of PKS 0237-23 determined by Greenstein and Sargent The average number
of acceptable redshifts per nonsense spectrum was 0.7. Five acceptable
redshifts were found in the real spectrum: z = 2 2015, 1.671, 1 656,
1.513, and 1.364 No acceptable redshift was found at z = 1 95. A list
of additional lines that should be detectable if the identifications
proposed here are correct is given for slightly longer and shorter
wavelengths than covered in the observa- tions of Greenstein and
Sargent Some characteristics of the identifications are also described
Title: Solar Models and Neutrino Fluxes
Authors: Bahcall, John N.; Shaviv, Giora
Bibcode: 1968ApJ...153..113B
Altcode:
We have derived a set of accurate models for the interior of the
present Sun by varying within their accepted limits all the parameters,
except the gravitational constant, at our disposal. Our principal
con- clusions are: (1) the 8B neutrino flux is 1.3(1 ± 0.6) X 10~
neutrinos cm2 sec1 at Earth's surface if the uncertainties are assumed
to combine like statistical errors; (2) the primordial helium mass
fraction probably lies in the range 0.24-0.28; (3) the primordial
heavy-element mass fraction probably lies in the range 0.018-0.036;
(4) the fraction of energy generated by the CNO cycle is 0.03 ± 0.02;
and (5) the luminosity of the Sun has increased by about 35 per cent in
the last 4.7 billion years. We also present three numerical models for
the solar interior and discuss some of their principal characteristics
Title: Neutrino absorption by deuterium
Authors: Ellis, S. D.; Bahcall, J. N.
Bibcode: 1968NuPhA.114..636E
Altcode:
The cross section for the reaction 2H(ν,e-)2p
has been calculated as a function of neutrino energy using the
effective range method to approximate the required nuclear matrix
element. The cross section was averaged over the shape of the neutrino
spectra from the decay of 15O and 8B. The
results are σav(15O)=1.05× 10 -47
cm2 and σav(8B)=1.20×10-42
cm2. The uncertainty of both values is estimated to be
+/-10%. Alfred P. Sloan Foundation Fellow.
Title: Fine-Structure Transitions
Authors: Bahcall, John N.; Wolf, Richard A.
Bibcode: 1968ApJ...152..701B
Altcode:
We calculate collision cross-sections and photon transition
probabilities for many cases of practical interest. Using the calculated
rates, we show how the fine structure of absorption lines can be used
as an indicator of the density of the absorbing medium or the ambient
intensity of a strong photon flux. For densities much greater than a
critical value, ~ or for very high photon fluxes, the fine-structure
levels of the ground state of a given ion are populated according
to a Boltzmann distribution (which for most practical cases means
according to the ratio of degeneracies) For densities much less than
Ncr and moderate photon fluxes, only the lowest fine structure state
is populated The value of N0~ is calculated for the most abundant ions
that have resonant absorption lines with wavelengths greater than 950
A by evaluating the rates of the photon and collisional transitions
among the fine structure levels. Cross-sec- tions for collisional
excitation by protons have been calculated by numerical integration
of the relevant time-dependent Schroedinger equation for six ions of
interest and these detailed calculations are used to obtain accurate
estimates of the proton-excitation cross-sections for a number of
other cases. The prob- ability of exciting fine-structure levels of
both neutral and charged ions by collisions with hydrogen atoms has
been estimated. The rates of magnetic-dipole photon decays, as well
as cross-sections for colli- sional excitation of fine-structure
levels by electrons, have been calculated from previously published
results. Applications are made to problems involving the interstellar
medium, circumstellar envelopes of giant stars, the solar corona,
planetary nebulae, the intergalactic medium, and quasi-stellar source
Title: Present Status of the Theoretical Predictions for the
36Cl Solar-Neutrino Experiment
Authors: Bahcall, John N.; Bahcall, Neta A.; Shaviv, Giora
Bibcode: 1968PhRvL..20.1209B
Altcode:
The theoretical predictions for the 37Cl solar-neutrino
experiment are summarized and compared with the experimental results
of Davis, Harmer, and Hoffman. Three important conclusions about the
sun are shown to follow.
Title: The Rate of the Proton-Proton Reaction
Authors: Bahcall, John N.; May, Robert M.
Bibcode: 1968ApJ...152L..17B
Altcode:
The rate of the proton-proton reaction has been recalculated. Our value
for the low-energy cross- section factor is S(E = 0) = (3.78 ± 0.15)
X 10-25 MeV barns, which is 12.5 per cent larger than the value in
current usage. The effect of our larger calculated S(E = 0) on the
8fi solar neutrino flux and on the rate of nuclear-energy generation
in the proton-proton chain is briefly discussed
Title: Electron Scattering and Tests of Cosmological Models
Authors: Bahcall, John N.; May, Robert M.
Bibcode: 1968ApJ...152...37B
Altcode:
We discuss the effect of photon scattering by electrons on the
magnitude-redshift, count-magnitude, and number-redshift relationships
in Friedmann cosmologies. I. INTRODUCTIO
Title: Mixing in the Sun and Neutrino Fluxes
Authors: Bahcall, J. N.; Bahcall, N. A.; Ulrich, R. K.
Bibcode: 1968ApL.....2...91B
Altcode:
No abstract at ADS
Title: Does the Fine-Structure Constant Vary with Cosmic Time?
Authors: Bahcall, John N.; Schmidt, Maarten
Bibcode: 1967PhRvL..19.1294B
Altcode:
The fine structure constant at red shifts Δλλ~0.2, corresponding
to an epoch around two billion years ago, has been determined using
the wavelengths of a pair of O III emission lines measured in the
spectra of five radio galaxies. We find α(z=0.2)α(lab)=1.001+/-0.002
probable error.
Title: Dependence of the ^8{B} Solar Neutrino Flux on the Rate of
the Reaction ^3He(^3He,2p)4He
Authors: Shaviv, Giora; Bahcall, John N.; Fowler, William A.
Bibcode: 1967ApJ...150..725S
Altcode:
No abstract at ADS
Title: Dependence of the ^8{B} Solar Neutrino Flux on Heavy Element
Composition
Authors: Bahcall, John N.; Cooper, Martin; Demarque, Pierre
Bibcode: 1967ApJ...150..723B
Altcode:
No abstract at ADS
Title: The Carbon to Silicon Ratio in 3C 191
Authors: Bahcall, J. N.; Kozlovsky, B. Z.; Sargent, W. L. W.;
Schmidt, M.
Bibcode: 1967PASP...79..425B
Altcode:
No abstract at ADS
Title: Brans-Dicke Cosmology and the Solar Neutrino Flux
Authors: Shaviv, G.; Bahcall, J. N.
Bibcode: 1967PASP...79..438S
Altcode:
No abstract at ADS
Title: Phenomenological Limits on the Absorbing Regions of
Quasi-Stellar Sources
Authors: Bahcall, John N.
Bibcode: 1967ApJ...149L...7B
Altcode:
No abstract at ADS
Title: An Analysis of the Absorption Spectrum of 3c 191
Authors: Bahcall, John N.; Sargent, Wallace L. W.; Schmidt, Maarten
Bibcode: 1967ApJ...149L..11B
Altcode:
No abstract at ADS
Title: Predicted Emission Spectra of Quasi-Stellar Sources in the
Far Ultraviolet
Authors: Bahcall, John N.; Sargent, Wallace L. W.
Bibcode: 1967ApJ...148L..65B
Altcode:
No abstract at ADS
Title: On the fine structure of absorption lines
Authors: Bahcall, J. N.; Wolf, R. A.; Salpeter, E. E.
Bibcode: 1967AJ.....72Q.290B
Altcode:
No abstract at ADS
Title: An Interpretation of the Absorption Spectrum of 3c 191
Authors: Bahcall, John N.
Bibcode: 1966ApJ...146..615B
Altcode:
No abstract at ADS
Title: On Some Predicted and Observed Features of Quasi-Stellar
Sources
Authors: Bahcall, John N.
Bibcode: 1966ApJ...145..684B
Altcode:
Some observed features of quasi-stellar sources are correlated in a way
that enables one to predict with simple models the relative strengths of
the Lyman lines and the optical depth of the nebulae beyond the Lyman
continuum. The relative strengths of the Lyman lines are calculated
first for an optically thin nebula, and then expressions are derived
for the amount by which the intensities of the more energetic Lyman
lines are attenuated in an optically thick nebula. The probability
that resonant radiation escapes from an optically thick nebula is
estimated with a diffusion equation and is found to be much larger than
previously estimated if some emission originates near the surface of
the nebula. Three possible causes for the observed emission widths are
discussed, and it is concluded that the most likely cause is random
motions of gas clumps or filaments. A suggestion due to Schmidt for
constructing models of quasi-stellar sources that are optically thin
to electron scattering is developed quantitatively. The average degree
of ionization of the hydrogen in a quasi-stellar source and the optical
depth beyond the Lyman continuum are expressed in terms of the unknown
ionizing flux. A plausible guess for the strength of the ionizing flux
indicates that some quasi-stellar sources may be optically thin beyond
the Lyman continuum. A possible correlation is suggested between the
age (and luminosity) of the nebula of a quasi-stellar source and the
value of its optical depth beyond the Lyman continuum. Several other
observational consequences of our discussion are also described. In
particular the predictions are shown to depend sensitively on whether
or not quasi-stellar sources are, like the nuclei of Seyfert galaxies,
surrounded by an appreciable amount of neutral hydrogen.
Title: Solar Neutrinos
Authors: Bahcall, John N.
Bibcode: 1966PhRvL..17..398B
Altcode:
The predicted capture rate in the Cl37 experiment for
detecting solar neutrinos is calculated using the results of recent
nuclear experiments and solar-model investigations. It is shown that
additional experiments (e.g., with H2, Li7,
B11, or ν-e scattering) are necessary to establish the
relative contributions of the proton-proton chain and the CNO cycle
to solar energy generation.
Title: On the Absorption Spectrum of 1116+12
Authors: Bahcall, John N.; Peterson, Bruce A.; Schmidt, Maarten
Bibcode: 1966ApJ...145..369B
Altcode:
No abstract at ADS
Title: Absorption Lines in the Spectra of Distant Sources
Authors: Bahcall, John N.; Salpeter, E. E.
Bibcode: 1966ApJ...144..847B
Altcode:
No abstract at ADS
Title: On the Problem of Detecting Solar Neutrinos
Authors: Bahcall, John N.; Davis, Raymond, Jr.
Bibcode: 1966stev.conf..241B
Altcode:
No abstract at ADS
Title: Non-Resonant Nuclear Reactions at Stellar Temperatures.
Authors: Bahcall, John N.
Bibcode: 1966ApJ...143..259B
Altcode:
No abstract at ADS
Title: Neutron Stars. II. Neutrino-Cooling and Observability
Authors: Bahcall, John N.; Wolf, Richard A.
Bibcode: 1965PhRv..140.1452B
Altcode:
Calculations of the rates of the cooling reactions
n+n-->n+p+e-+νe and
n+π--->n+e-+νe are presented;
the rates of the closely related muon-producing reactions and the
four inverse processes are also given. Several different arguments
are used to obtain estimates of the relavant matrix elements. The
nucleons are assumed to form a normal Fermi fluid with a continuous
excitation spectrum. The calculated cooling rates indicate that
a neutron star containing quasifree pions would cool within a few
days to a temperature so low that the star would be unobservable. The
surface of a star that does not contain quasifree pions would cool to
107 °K in a few months and would reach 4×106
°K in about 100 years. The calculated cooling rates strongly indicate
that the discrete x-ray sources located in the direction of the galactic
center are not neutron stars.
Title: Neutron Stars. I. Properties at Absolute Zero Temperature
Authors: Bahcall, John N.; Wolf, Richard A.
Bibcode: 1965PhRv..140.1445B
Altcode:
The properties of a neutron star at absolute zero temperature are
discussed. The problem of determining the ground state of a neutron
star is formulated in a general way and the conditions are described
under which one might reasonably hope that an individual-particle model
(which we adopt) is valid. The effects of the strong interactions on
the number densities and production thresholds of the various hadrons
are illustrated with several examples. The modification of the energy
spectrum of neutrons and protons in a neutron star is calculated using
an effective-mass approximation adapted from the theory of nuclear
matter. Crude estimates are made of the contributions of hadrons other
than nucleons to the equation of state and specific heat.
Title: On the Interaction of Radiation from Distant Sources with
the Intervening Medium.
Authors: Bahcall, John N.; Salpeter, E. E.
Bibcode: 1965ApJ...142.1677B
Altcode:
No abstract at ADS
Title: An Observational Test of Theories of Neutron-Star Cooling.
Authors: Bahcall, John N.; Wolf, Richard A.
Bibcode: 1965ApJ...142.1254B
Altcode:
No abstract at ADS
Title: Neutron Stars
Authors: Bahcall, John N.; Wolf, Richard A.
Bibcode: 1965PhRvL..14..343B
Altcode:
No abstract at ADS
Title: Observational Neutrino Astronomy
Authors: Bahcall, John N.
Bibcode: 1965Sci...147..115B
Altcode:
No abstract at ADS
Title: Neutrino-spectroscopy of the solar interior
Authors: Bahcall, J. N.
Bibcode: 1964PhL....13..332B
Altcode:
No abstract at ADS
Title: Neutrino Opacity. II. Neutrino-Nucleon Interactions
Authors: Bahcall, John N.; Frautschi, Steven C.
Bibcode: 1964PhRv..136.1547B
Altcode:
The contribution of neutrino-nucleon interactions to the neutrino
opacity of matter is studied, special attention being paid to possible
astrophysical applications such as supernova explosions. The results
of recent accelerator experiments with high-energy neutrinos are
used to show that nonresonant neutrino-nucleon scattering does
not make a significant contribution to the neutrino opacity for
astrophysically important conditions. The results of deep-mine
cosmic-ray studies are then used to show that, (a) there are no
resonances in the νμ-nucleon and ν¯μ-nucleon
systems with masses less than 60 BeV (laboratory neutrino energies
<2×10+3 BeV), and (b) there are no resonances in the
νe-neucleon and ν¯e-nucleon systems with masses
less than 7 BeV (laboratory neutrino energies <30 BeV). Neutrino
absorption by bound nucleons is also discussed and a sum rule is
proved for neutrino capture that is sufficiently accurate for most
astrophysical applications. The effect of the exclusion principle on the
capture cross sections is described and some applications to specific
nuclei are presented. The accelerator experiments with high-energy
neutrinos are then used to show that neutrino radioactivity, i.e.,
nuclear de-excitation by emission of a neutrino-antineutrino pair,
is a substantially less important mechanism for stellar energy loss
than was suggested by some previous estimates.
Title: Neutrino Opacity I. Neutrino-Lepton Scattering
Authors: Bahcall, John N.
Bibcode: 1964PhRv..136.1164B
Altcode:
The contribution of neutrino-lepton scattering to the total neutrino
opacity of matter is investigated; it is found that, contrary
to previous beliefs, neutrino scattering dominates the neutrino
opacity for many astrophysically important conditions. The rates for
neutrino-electron scattering and antineutrino-electron scattering
are given for a variety of conditions, including both degenerate and
nondegenerate gases; the rates for some related reactions are also
presented. Formulas are given for the mean scattering angle and the mean
energy loss in neutrino and antineutrino scattering. Applications are
made to the following problems: (a) the detection of solar neutrinos;
(b) the escape of neutrinos from stars; (c) neutrino scattering in
cosmology; and (d) energy deposition in supernova explosions.
Title: Neutrino Astronomy and Intermediate Bosons
Authors: Bahcall, John N.; Frautschi, Steven C.
Bibcode: 1964PhRv..135..788B
Altcode:
Neutrino fluxes from strong radio sources are
estimated, assuming the neutrino-production mechanism:
p+p-->nucleons+mesons-->nucleons+electrons, gamma rays, and
neutrinos. The neutrino fluxes calculated on the basis of this mechanism
are too small to be easily detected unless there are resonances in
neutrino processes associated with the production of intermediate
bosons. It is shown that a resonance in the antineutrino-electron
system, associated with the usually hypothesized W-
resonance, could be used to test, with standard experimental techniques,
whether strong radio sources emit high-energy neutrinos in the
quantities estimated in this paper. Two kinds of observational tests
are described and counting rates are estimated. Observational tests
of the kind we propose would provide important information about:
(1) the mechanism for production of high-energy electrons in strong
radio sources, and (2) the magnetic fields in such sources. Some
comments concerning other logically possible neutrino resonances are
also included.
Title: Termination of the Proton-Proton Chain in Stellar Interiors.
Authors: Parker, Peter D.; Bahcall, John N.; Fowler, William A.
Bibcode: 1964ApJ...139..602P
Altcode:
The roles of the various H2-burning and He3-burning reactions in
the termination of the proto proton chain in stellar interiors have
been re-examined using (1) recent experimental determinations the
cross-sections for the H2(p, )He3 and He3(a, )Be7 reactions, (2)
theoretical studies of the rates the relevant beta-decay reactions,
and (3) a re-examination of the previous cross-section factor detern
nations for the other possible reactions in the proton-proton chain.
Title: Terminating the Proton-Proton Chain at High Densities.
Authors: Bahcall, John N.; Wolf, Richard A.
Bibcode: 1964ApJ...139..622B
Altcode:
The rate of the He3(e , ) reaction is calculated as a function
of stellar temperature and den. using the modern theory of nuclear
beta-decay. Three tritium-burning sequences of nuclear reactions also
studied. Some possible applications are discussed briefly.
Title: Electron Capture in Stellar Interiors.
Authors: Bahcall, John N.
Bibcode: 1964ApJ...139..318B
Altcode:
The reasons why nuclear electron-capture rates in stars depend
on temperature and density are discussed, and some astrophysical
applications of continuum electron-capture rates are reviewed. The
modern theory of nuclear P-decay is then used to calculate
stellar-continuum electron-capture rates for transitions of an
arbitrary degree of forbiddenness. The equations that are most useful
for astrophysical applications are discussed in detail; particular
emphasis is placed upon methods for predicting stellar rates that
utilize, whenever possible, terrestrial measurements. Three examples are
discussed that illustrate the use of the formulae given in this paper;
the examples are: (a) the electron-capture lifetime of a proton, (b)
the stellar p-decay of K40, and (c) the effect of forbidden transitions
on the abundances of elements in the iron peak.
Title: Exclusion Principle Inhibition of Beta Decay in Stellar
Interiors.
Authors: Peterson, Vern L.; Bahcall, John N.
Bibcode: 1963ApJ...138..437P
Altcode:
Beta decay in a high-density electron gas is investigated. It is shown
that the exclusion principle can play an important role in determining
the decay rate Tables describing allowed, flrst4orbidden non- unique,
and first-forbidden unique decays are presented; these tables give
the dependence of the beta- decay rate on the local temperature,
electron density, and beta-decay energy. If the Fermi energy of
the free electrons exceeds the beta-decay energy, the decay rate is
strongly inhibited; the amount of inhibition decreases with increasing
temperature. The relativistic dependence of the degeneracy parameter
on temperature and electron density is also tabulated.
Title: Solar Neutrino Flux.
Authors: Bahcall, J. N.; Fowler, William A.; Iben, I., Jr.; Sears,
R. L.
Bibcode: 1963ApJ...137..344B
Altcode:
No abstract at ADS
Title: Exclusion principle inhibition of beta decay in stellar
interiors
Authors: Peterson, Vern Leroy; Bahcall, John N.
Bibcode: 1963PGLO...54..437P
Altcode:
No abstract at ADS
Title: The Exclusion Principle and Photobeta Reactions in
Nucleogenesis.
Authors: Bahcall, John N.
Bibcode: 1962ApJ...136..445B
Altcode:
The effects of the exclusion principle and photobeta reactions on the
formation of heavy elements by slow-neutron capture are discussed. It
is shown that a measurement of the isotopic abundance of Zr93 in giant
stars exhibiting technetium lines would permit inferences concerning
the temperature of the nuclear reacting core in which the heavy elements
were produced.
Title: Beta Decay in Stellar Interiors
Authors: Bahcall, John N.
Bibcode: 1962PhRv..126.1143B
Altcode:
A study is made of the temperature and density dependence of beta-decay
rates as they are affected by electron capture from continuum orbits,
the absence of atomic binding energies, screening, and the exclusion
principle. The rate of allowed electron capture from continuum orbits
in a Fermi gas is calculated using the V-A law; Coulomb corrections
are included and nuclear matrix elements occur as parameters that can
frequently be determined from terrestrial experiments. There is no
atomic binding-energy contribution to the total beta-decay energy
for completely ionized atoms and this causes a decrease in decay
rates for low-energy electron emitters in stars relative to their
terrestrial values. Screening will usually not affect beta-decay rates
significantly. The exclusion principle inhibits beta decay in stellar
interiors because many of the low-momentum states are occupied prior
to the decay; the amount by which a decay rate is decreased can be
calculated in terms of the known beta spectrum and the temperature
and density of the medium surrounding the radioactive nucleus. Beta
decay for some normally radioactive nuclei is almost impossible in the
interior of very dense stars, such as white dwarfs, since the Fermi
energy can equal or exceed the maximum beta-decay energy available. Some
applications to the theory of element formation in stars are suggested.
Title: Theory of Bound-State Beta Decay
Authors: Bahcall, John N.
Bibcode: 1961PhRv..124..495B
Altcode:
The theory of beta-decay processes in which an electron is
created in a bound atomic state is developed in the allowed
approximation. The correlations and total decay rate are calculated
with the renormalized V-A theory and the results are valid for atoms
of arbitrary electronic configuration. The relative probability of
bound-state to continuum-state decay is shown to be independent of
nuclear matrix elements; some bound-state decay rates are presented
that were calculated by making use of this fact. The possibility of
experimentally detecting bound-state decay is also briefly examined. The
beta decay of nuclei in stellar interiors is discussed and a number
of examples are presented for which bound-state decay is more likely
than continuum-state decay under the conditions that obtain in stellar
interiors.