Author name code: goldberg
ADS astronomy entries on 2022-09-14
author:Goldberg, L.
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Title: A new estimate of galaxy mass-to-light ratios from flexion
lensing statistics
Authors: Fabritius, Joseph M.; Goldberg, David M.
Bibcode: 2022MNRAS.515.6191F
Altcode: 2022MNRAS.tmp.2142F; 2021arXiv210805453F
We perform a flexion-based weak gravitational analysis of the first two
Hubble Frontier Field clusters: Abell 2744 and MACS 0416. A parametric
method for using radially projected flexion signals as a probe of
cluster member mass is described in detail. The normalization and slope
of a L - θE (as a proxy for L - σ) scaling relation in
each cluster is determined using measured flexion signals. A parallel
field analysis is undertaken concurrently to provide a baseline measure
of method effectiveness. We find an agreement in the Faber-Jackson
slope ℓ associated with galaxy age and morphology for both clusters,
as well as a theoretical distinction in the cluster normalization mass.
Title: Shock Breakout in Three-dimensional Red Supergiant Envelopes
Authors: Goldberg, Jared A.; Jiang, Yan-Fei; Bildsten, Lars
Bibcode: 2022ApJ...933..164G
Altcode: 2022arXiv220604134G
Using Athena++, we perform 3D radiation-hydrodynamic calculations of
the radiative breakout of the shock wave in the outer envelope of a
red supergiant (RSG) that has suffered core collapse and will become
a Type IIP supernova. The intrinsically 3D structure of the fully
convective RSG envelope yields key differences in the brightness
and duration of the shock breakout (SBO) from that predicted in a 1D
stellar model. First, the lower-density "halo" of material outside
of the traditional photosphere in 3D models leads to a shock breakout
at lower densities than 1D models. This would prolong the duration of
the shock breakout flash at any given location on the surface to ≍1-2
hr. However, we find that the even larger impact is the intrinsically 3D
effect associated with large-scale fluctuations in density that cause
the shock to break out at different radii at different times. This
substantially prolongs the SBO duration to ≍3-6 hr and implies a
diversity of radiative temperatures, as different patches across the
stellar surface are at different stages of their radiative breakout
and cooling at any given time. These predicted durations are in
better agreement with existing observations of SBO. The longer
durations lower the predicted luminosities by a factor of 3-10 (L
bol ~ 1044 erg s-1), and we derive
the new scalings of brightness and duration with explosion energies
and stellar properties. These intrinsically 3D properties eliminate
the possibility of using observed rise times to measure the stellar
radius via light-travel time effects.
Title: Numerical Simulations of Convective Three-dimensional Red
Supergiant Envelopes
Authors: Goldberg, Jared A.; Jiang, Yan-Fei; Bildsten, Lars
Bibcode: 2022ApJ...929..156G
Altcode: 2021arXiv211003261G
We explore the three-dimensional properties of convective, luminous (L
≍ 104.5-105 L ⊙), hydrogen-rich
envelopes of red supergiants (RSGs) based on radiation hydrodynamic
simulations in spherical geometry using Athena++. These computations
comprise ≍30% of the stellar volume, include gas and radiation
pressure, and self-consistently track the gravitational potential for
the outer ≍3M ⊙ of the simulated M ≍ 15M ⊙
stars. This work reveals a radius, R corr, around which
the nature of the convection changes. For r > R corr,
though still optically thick, diffusion of photons dominates the energy
transport. Such a regime is well studied in less luminous stars, but
in RSGs, the near- (or above-)Eddington luminosity (due to opacity
enhancements at ionization transitions) leads to the unusual outcome
of denser regions moving outward rather than inward. This region of the
star also has a large amount of turbulent pressure, yielding a density
structure much more extended than 1D stellar evolution predicts. This
"halo" of material will impact predictions for both shock breakout and
early lightcurves of Type IIP supernovae. Inside of R corr,
we find a nearly flat entropy profile as expected in the efficient
regime of mixing-length theory (MLT). Radiation pressure provides
≍1/3 of the support against gravity in this region. Our comparisons
to MLT suggest a mixing length of α = 3-4, consistent with the sizes
of convective plumes seen in the simulations. The temporal variability
of these 3D models is mostly on the timescale of the convective plume
lifetimes (≍300 days), with amplitudes consistent with those observed
photometrically.
Title: Hydrogeochemical modelling of origin, evolution and mechanisms
controlling water resources quality in the Pra Basin (Ghana)
Authors: Manu, Evans; Kühn, Michael; Kempka, Thomas; Goldberg,
Tatiana; Vieth-Hillebrand, Andrea; Rach, Oliver
Bibcode: 2021EGUGA..23.7800M
Altcode:
Understanding the geochemistry of water resources is a prerequisite
in the development of sustainable water resource management
strategies. The Pra Basin is one of the few basins in Ghana with
economic importance. The Basin is constituted by three river systems
(Birim, Offin and Pra) and covers a total land size of approximately
2,300 km2. It traverses several towns and serves as the main water
supply for communities and industry. Currently, the quality of water
resources in the Pra Basin especially surfacewaters have been affected
negatively as a result of activities such as illegal mining (e.g.,
the use of mercury for the extraction of gold), indiscriminate waste
disposal, and poor farm management practices (e.g., inappropriate
application of fertilizers and pesticides). Specific contaminants
include mercury (Hg), arsenic (As), lead (Pb), iron (Fe), manganese
(Mn), cadmium (Cd), selenium (Se), and nitrate (NO3). The Pra Basin
is underlain by three rock formations, the Birimian Supergroup, the
Tarkwain Formation and the granitoids. The mineral composition of
the Birimian Supergroup comprises argillitic/pellitic sediment (plus
or minus kerogen), sericite schist, and quartz-sericite schist. The
granitoids comprise biotite (hornblende, muscovite), biotite gneiss,
biotite schist, amphibolite partly of contact metamorphism, K-feldspar
rich granitoid, two-mica or muscovite granite and monzonite, serecite
schist, quartz-serecite, and garnet. The Tarkwaian rocks mineralogy
also includes basaltic flow/subvolcanic rock and minor interbedded
volcaniclastics, detrital sediment mainly sandstone and conglomerate
ultramafic and minor mafic igneous rock. Samples of groundwater were
collected from shallow (mainly hand-dug wells of depths < 10 m)
and deep (mainly boreholes of depths >30 m) aquifers across the Pra
Basin. Surfacewaters were collected from rivers and stream networks. The
samples were analysed for major ions, trace metals and stable isotopes
(oxygen-18 and deuterium) using Inductively Coupled Plasma Optical
Emission Spectrometry (ICP-OES), Ion Chromatography (IC), and Picarro
L-2140i Ringdown Spectrometer at the GFZ laboratories. Multivariate
statistical analysis and inverse geochemical modelling have been
applied to around 100 water samples sourced from boreholes, hand-dug
wells, and rivers of the Pra Basin to determine the chemical state
of the waters. Specifically, the study seeks to (1) determine the
origin and evolution of the geochemistry of both surfacewater and
groundwater, (2) identify recharge and discharge areas, and (3)
study sources and sinks of minerals including sulphates, carbonates,
and silicates. The abundance of cations and anions are in the order
of Na>Ca>K>Mg and HCO3>Cl>SO4>NO3 (surfacewater),
Na>Ca>Mg>K and HCO3>Cl>NO3>SO4 (hand-dug well),
and Na>Ca>Mg>K, and HCO3>Cl>NO3>SO4 (boreholes). Our
research findings demonstrate that geochemistry of water resources in
the Pra Basin is mainly controlled by rock-water interaction. With
the application of hydrogeochemical modelling, including silicate
mineral weathering and ion exchange, significant processes controlling
the basin"s hydrochemistry variations are quantified. The presented
results will support the development of sustainable water resources
management strategies and contribute to mitigating future contamination.
Title: Evidence for α -cluster structure in 21Ne in the
first measurement of resonant 17O+α elastic scattering
Authors: Nurmukhanbetova, A. K.; Goldberg, V. Z.; Nauruzbayev, D. K.;
Golovkov, M. S.; Volya, A.
Bibcode: 2019PhRvC.100f2802N
Altcode:
The first study of resonances in 17O+α elastic scattering
was carried out using the thick target inverse kinematics method. The
data were analyzed in the framework of an R-matrix approach. Many α
-cluster states were found in the 21Ne excitation region
of the 9-13 MeV excitation energy including the first observation of
a broad l =0 state in an odd-even nucleus, which is likely the analog
of the broad 0+ at 8 MeV in 20Ne. The observed
structure in 21Ne appeared to be strikingly similar
to that populated in the resonant 16O+α scattering in
20Ne. The results are also useful for refinement of data
on an 17O(α ,n ) reaction important for astrophysics.
Title: LHC phenomenology and cosmology of string-inspired intersecting
D-brane models
Authors: Anchordoqui, Luis A.; Antoniadis, Ignatios; Goldberg, Haim;
Huang, Xing; Lüst, Dieter; Taylor, Tomasz R.; Vlcek, Brian
Bibcode: 2012PhRvD..86f6004A
Altcode: 2012arXiv1206.2537A
We discuss the phenomenology and cosmology of a Standardlike Model
inspired by string theory, in which the gauge fields are localized on
D-branes wrapping certain compact cycles on an underlying geometry,
whose intersection can give rise to chiral fermions. The energy
scale associated with string physics is assumed to be near the
Planck mass. To develop our program in the simplest way, we work
within the construct of a minimal model with gauge-extended sector
U(3)B×Sp(1)L×U(1)IR×U(1)L.
The resulting U(1) content gauges the baryon number B, the lepton number
L, and a third additional Abelian charge IR which acts as
the third isospin component of an SU(2)R. All mixing angles
and gauge couplings are fixed by rotation of the U(1) gauge fields
to a basis diagonal in hypercharge Y and in an anomaly-free linear
combination of IR and B-L. The anomalous Z'
gauge boson obtains a string scale Stückelberg mass via a 4D version
of the Green-Schwarz mechanism. To keep the realization of the Higgs
mechanism minimal, we add an extra SU(2) singlet complex scalar,
which acquires a VEV and gives a TeV-scale mass to the nonanomalous
gauge boson Z''. The model is fully predictive and can be
confronted with dijet and dilepton data from LHC8 and, eventually,
LHC14. We show that MZ''≈3-4TeV saturates
current limits from the CMS and ATLAS Collaborations. We also show
that for MZ''≲5TeV, LHC14 will reach discovery
sensitivity ≳5σ. After that, we demonstrate in all generality that
Z'' milliweak interactions could play an important role
in observational cosmology. Finally, we examine some phenomenological
aspects of the supersymmetric extension of the D-brane construct.
Title: Neutrino Cosmology after WMAP 7-Year Data and LHC First
Z' Bounds
Authors: Anchordoqui, Luis Alfredo; Goldberg, Haim
Bibcode: 2012PhRvL.108h1805A
Altcode: 2011arXiv1111.7264A
The gauge-extended
U(1)C×SU(2)L×U(1)IR×U(1)L
model elevates the global symmetries of the standard model (baryon
number B and lepton number L) to local gauge symmetries. The
U(1)L symmetry leads to three superweakly interacting
right-handed neutrinos. This also renders a B-L symmetry
nonanomalous. The superweak interactions of these Dirac states permit
νR decoupling just above the QCD phase transition:
175≲TνRdec/MeV≲250. In
this transitional region, the residual temperature ratio between
νL and νR generates extra relativistic degrees
of freedom at BBN and at the CMB epochs. Consistency with both WMAP
7-year data and recent estimates of the primordial He4 mass fraction
is achieved for 3<MB-L/TeV<6. The model is fully
predictive, and can be confronted with dijet and dilepton data from
LHC7 and, eventually, LHC14.
Title: Supernova 2011dw in Pgc 58436 = Psn J16313945+4129229
Authors: Pelloni, A.; Newton, J.; Puckett, T.; Leonard, D. C.;
Moustakas, J.; Swift, B. J.; McCarthy, D.; Bailey, V.; Carrico, E.;
Carter, A.; Chui, E.; Douglas, E.; Eggeman, E.; Goldberg, R.; Grant,
R.; Hartman, K.; Hellerstein, J.; Hooper, E.; Horlick-Cruz, C.; Hunter,
L.; Jiles, T.; Johnson, E. D.; Kumar, K.; Lappe, L.; Lee, J.; Lee,
W.; Marsh, F.; Mehta, G.; Miller, P.; Rampalli, R.; Reed, J.; Rice,
K.; Saldivar, H.; Salgado-Flores, M.; Schlingman, A.; Scibelli, S.;
Sinclair, K.; Steincamp, I.; Stock, N.; Todd, N.; Aizpuru Vargas,
L. L.; Yamanaka, S.; Zachary, E.
Bibcode: 2011CBET.2756....1P
Altcode: 2011CBET.2756A...1P
A. Pelloni, J. Newton, and T. Puckett report the discovery of
an apparent supernova (mag 17.5) on an unfiltered CCD image
(limiting mag 19.0) taken with a 0.35-m reflector at Portal, AZ,
U.S.A., on June 24.3395 UT in the course of the Puckett Observatory
Supernova Search. The new object, which was confirmed at mag 16.9
on June 27.3391 by Puckett with the 40-cm reflector at Portal,
is located at R.A. = 16h31m39.45 Decl. = +41o29'22".9 (equinox
2000.0), which is 17".3 east and 14".0 south of the center of PGC
58436. Nothing is visible at this position on images taken by Puckett
on 2011 June 9 (limiting mag 19.1). The variable was designated PSN
J16313945+4129229 when posted on the Central Bureau's TOCP webpage
and is here designated SN 2011dw based on the spectroscopic report
below. Puckett has posted a finder image for 2011dw at website URL
http://possdata.com/PSNJ16313945+4129229.jpg. D. C. Leonard, San
Diego State University; J. Moustakas, University of California at San
Diego; B. J. Swift and D. McCarthy, University of Arizona; V. Bailey,
E. Carrico, A. Carter, E. Chui, E. Douglas, E. Eggeman, R. Goldberg,
R. Grant, K. Hartman, J. Hellerstein, E. Hooper, C. Horlick-Cruz,
L. Hunter, T. Jiles, E. D. Johnson, K. Kumar, L. Lappe, J. Lee,
W. Lee, F. Marsh, G. Mehta, P. Miller, R. Rampalli, J. Reed, K. Rice,
H. Saldivar, M. Salgado-Flores, A. Schlingman, W. F. Schlingman,
W. M. Schlingman, S. Scibelli, K. Sinclair, I. Steincamp, N. Stock,
N. Todd, L. L. Aizpuru Vargas, S. Yamanaka, and E. Zachary, 2011
Advanced Teen Astronomy Camp, report that a low-dispersion optical
spectrum (range 370-690 nm) of PSN J16313945+4129229 = SN 2011dw,
obtained with the 2.3-m Bok telescope (+ Boller & Chivens
spectrograph) at Steward Observatory on June 30 UT, displays a
featureless, blue continuum. Identifying a faint, unresolved emission
line in the spectrum at 675.8 nm with H-alpha indicates a redshift of
0.03, in agreement with the recession velocity reported in the second
Sloan Digital Sky Survey Data Release of the putative host galaxy,
PGC 58436. The spectrum is reminiscent of a very young type-II/IIb
supernova, although additional spectroscopy is required to confirm the
nature of this event. Adopting the NASA/IPAC Extragalactic Database
distance-modulus estimate of PGC 58436 of m-M = 35.5 magnitudes,
that the apparent magnitude of PSN J16313945+4129229 (16.9 on June
27.3391, as reported by the discoverers, above) indicates an absolute
magnitude of -18.6, which is a somewhat-greater luminosity than typical
type-II/IIb supernovae achieve.
Title: Supernova 2011dv in NGC 6078 = Psn J16120400+1412330
Authors: Ciabattari, F.; Dimai, A.; Leonini, S.; Leonard, D. C.;
Moustakas, J.; Swift, B. J.; McCarthy, D.; Bailey, V.; Carrico, E.;
Carter, A.; Chui, E.; Douglas, E.; Eggeman, E.; Goldberg, R.; Grant,
R.; Hartman, K.; Hellerstein, J.; Hooper, E.; Horlick-Cruz, C.; Hunter,
L.; Jiles, T.; Johnson, E. D.; Kumar, K.; Lappe, L.; Lee, J.; Lee,
W.; Marsh, F.; Mehta, G.; Miller, P.; Rampalli, R.; Reed, J.; Rice,
K.; Saldivar, H.; Salgado-Flores, M.; Schlingman, A.; Schlingman,
W. F.; Scibelli, S.; Sinclair, K.; Steincamp, I.; Stock, N.; Todd,
N.; Aizpuru Vargas, L. L.; Yamanaka, S.; Zachary, E.; Balam, D. D.;
Graham, M. L.; Hsiao, E. Y.; Green, D. W. E.
Bibcode: 2011CBET.2755....1C
Altcode: 2011CBET.2755A...1C
F. Ciabattari, Borgo a Mozzano, Italy, reports the discovery of a point-
like object (mag 16.2) on unfiltered CCD images (limiting magnitude
19.2) obtained on June 28.86 UT with a 0.5-m Newtonian telescope in
the course of the Italian Supernovae Search Project, the new object
being located at R.A. = 16h12m04s.62, Decl. = +14d12'33".2 (equinox
2000.0; astrometry with respect to UCAC-2 stars), which is 13" west
of the center of the galaxy NGC 6078. The variable was designated
PSN J16120400+1412330 when posted on the Central Bureau's TOCP
webpage and is here designated SN 2011dv based on the spectroscopic
confirmation reported below. Additional magnitudes for 2011dv as
provided by Ciabattari: 1992 Apr. 30, [20.3 (Palomar Sky Survey, J
plate); 1994 June 8, [20.3 (Palomar Sky Survey, F plate); 2010 June,
[19.1 (images taken by Ciabattari); 2011 June 29.98 UT, 16.0 (A. Dimai,
Cortina d'Ampezzo, Italy; and S. Leonini, Siena, Italy; remotely using
the GRAS-7 PlaneWave 43-cm CDK telescope in Spain). D. C. Leonard, San
Diego State University; J. Moustakas, University of California at San
Diego; B. J. Swift and D. McCarthy, University of Arizona; V. Bailey,
E. Carrico, A. Carter, E. Chui, E. Douglas, E. Eggeman, R. Goldberg,
R. Grant, K. Hartman, J. Hellerstein, E. Hooper, C. Horlick-Cruz,
L. Hunter, T. Jiles, E. D. Johnson, K. Kumar, L. Lappe, J. Lee,
W. Lee, F. Marsh, G. Mehta, P. Miller, R. Rampalli, J. Reed, K. Rice,
H. Saldivar, M. Salgado-Flores, A. Schlingman, W. F. Schlingman,
W. M. Schlingman, S. Scibelli, K. Sinclair, I. Steincamp, N. Stock,
N. Todd, L. L. Aizpuru Vargas, S. Yamanaka, and E. Zachary, 2011
Advanced Teen Astronomy Camp, report that inspection of a low-dispersion
optical spectrum (range 370-690 nm) of PSN J16120400+1412330 = SN
2011dv, obtained with the 2.3-m Bok telescope (+ Boller & Chivens
spectrograph) at Steward Observatory on June 30 UT, shows it to be a
normal type-Ia supernova near maximum light. Cross-correlation with
a library of supernova spectra using the "Supernova Identification"
code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) finds good
matches with near-maximum (2 +/- 6 days) template spectra of SN
1992A and SN 2002bo. Adopting the NASA/IPAC Extragalactic Database
recession velocity for NGC 6078 of 9378 km/s (Falco et al. 1999,
PASP 111, 438), the maximum absorption in the Si II line (rest 635.5
nm) is blueshifted by approximately 13600 km/s. D. D. Balam, Dominion
Astrophysical Observatory, National Research Council of Canada (NRCC);
M. L. Graham, Las Cumbres Observatory Global Telescope, University of
California at Santa Barbara; E. Y. Hsiao, Lawrence Berkeley Laboratory;
and D. W. E. Green, Harvard University, report that a spectrogram
(range 389-725 nm., resolution 0.3 nm) of PSN J16120400+1412330 = SN
2011dv, obtained on June 30.27 UT with the 1.82-m Plaskett Telescope
of the NRCC, shows it to be a type-Ia supernova about five days past
maximum light. Cross-correlation with a library of supernova spectra
using the SNID code indicates that 2011dv is most similar to the
type-Ia supernova 2006gz at five days past maximum light.
Title: Supernova 2011dn in UGC 11501 = Psn J19583553+0236163
Authors: Koff, R. A.; Leonard, D. C.; Moustakas, J.; Swift, B. J.;
McCarthy, D.; Bailey, V.; Carrico, E.; Carter, A.; Chui, E.; Douglas,
E.; Eggeman, E.; Goldberg, R.; Grant, R.; Hartman, K.; Hellerstein, J.;
Hooper, E.; Horlick-Cruz, C.; Hunter, L.; Jiles, T.; Johnson, E. D.;
Kumar, K.; Lappe, L.; Lee, J.; Lee, W.; Marsh, F.; Mehta, G.; Miller,
P.; Rampalli, R.; Reed, J.; Rice, K.; Saldivar, H.; Salgado-Flores,
M.; Schlingman, A.; Scibelli, S.; Sinclair, K.; Steincamp, I.; Stock,
N.; Todd, N.; Aizpuru Vargas, L. L.; Yamanaka, S.; Zachary, E.
Bibcode: 2011CBET.2746....2K
Altcode:
Additional unfiltered CCD magnitudes for SN 2011dn: June
23.23-23.30 UT, 16.5 (R. A. Koff, Bennett, CO, U.S.A.; Celestron
0.20-m f/10 reflector + SBIG ST-6 CCD camera; multiple co-added
images); 23.354, 16.1 (Joseph Brimacombe, Cairns, Australia;
three co-added 60-s images; position end figures 35s.56,
11".3). Brimacombe's image is posted at the following website URL:
http://www.flickr.com/photos/43846774@N02/5865118910/. D. C. Leonard,
San Diego State University; J. Moustakas, University of California
at San Diego; B. J. Swift and D. McCarthy, University of Arizona;
V. Bailey, E. Carrico, A. Carter, E. Chui, E. Douglas, E. Eggeman,
R. Goldberg, R. Grant, K. Hartman, J. Hellerstein, E. Hooper,
C. Horlick-Cruz, L. Hunter, T. Jiles, E. D. Johnson, K. Kumar,
L. Lappe, J. Lee, W. Lee, F. Marsh, G. Mehta, P. Miller, R. Rampalli,
J. Reed, K. Rice, H. Saldivar, M. Salgado-Flores, A. Schlingman,
W. F. Schlingman, W. M. Schlingman, S. Scibelli, K. Sinclair,
I. Steincamp, N. Stock, N. Todd, L. L. Aizpuru Vargas, S. Yamanaka,
and E. Zachary, 2011 Advanced Teen Astronomy Camp, report that
inspection of a low-dispersion optical spectrum (range 370-690 nm)
of PSN J19583553+0236163 = SN 2011dn, obtained with the 2.3-m Bok
telescope (+ Boller & Chivens spectrograph) at Steward Observatory
on June 23 UT, shows it to be a type-Ia supernova of the SN-1991T-like
sub-class, several days before maximum light. Cross-correlation with
a library of supernova spectra using the "Supernova Identification"
code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) finds good matches
with pre-maximum (-6.4 +/- 2.7 days) template spectra of SN 1991T, SN
1997br, and SN 1999aa. Adopting the NASA/IPAC Extragalactic Database
(NED) recession velocity for UGC 11501 of 7572 km/s (a 21-cm H I line
measurement taken from Springob et al. 2005, Ap.J. Suppl. 160, 149),
the maximum absorption in the (weak) Si II line (rest 635.5 nm) is
blueshifted by approximately 10100 km/s.
Title: Waiting Points and Bottlenecks in Nova and X-ray Burst
Nucleosynthesis
Authors: Goldberg, Leah
Bibcode: 2010APS..DNP.EA044G
Altcode:
At Oak Ridge National Laboratory, we are investigating nucleosynthesis
in nova explosions and X-ray bursts, specifically at ``waiting points''
and ``bottlenecks'' -- unusual phenomenon in which nuclei interrupt
the sequence of thermonuclear reactions that form heavier elements
from lighter ones, significantly affecting the final abundances and
the energy generation rate in stellar explosions. Nuclei identified
as waiting points or bottlenecks seem to play a more important role in
explosions and need to be singled out for further investigation. Such
points are defined by a series of acceptance and rejection tests in
a simulation, Computational Infrastructure for Nuclear Astrophysics
(CINA), in which a suite of codes visualizes nucleosynthesis over a
specified time interval and allows us, for each nucleus, to consider
eight surrounding nuclei in the Z=N plane based on possible reaction
paths in the rp-process. After considering abundance, lifetime and
reaction flux, reaction rate, and reaction Q-value, we accept or reject
accordingly, and can then better ascertain the relationship between
waiting points and bottlenecks and nuclear flow.
Title: Experimental Evidence Leading to an Alternative Explanation
of Why D-tyrosine Sometimes Crystallizes Faster than Its L-Enantiomer
Authors: Goldberg, Stanley I.
Bibcode: 2008OLEB...38..149G
Altcode: 2008OLEB..tmp....5G
On the occasions when D-tyrosine is observed to crystallize faster than
its L-enantiomer, it is the result of a diastereomeric interaction
between an airborne, non-racemic, chiral influence—probably a
fungal spore—and the tyrosine enantiomers, enhancing the degree of
crystal nucleation of D-tyrosine over L-tyrosine. This explanation,
supported by experimental evidence, is presented as a more plausible
alternative to the Shinitzky Deamer hypothesis (Shinitzky et al.,
Progress in biological chirality, Elsevier, Amsterdam, pp. 329 337,
2004; Deamer et al., Chirality, 19:751 763, 2007) which relies on the
parity violation energy difference between enantiomers, a femtojoule
to picojoule per mole theoretical energy range.
Title: A Study of the ^14C(?,?) Reaction Rate Through the ANC
Technique
Authors: Johnson, E. D.; Rogachev, G. V.; Mukhamedzhanov, A. M.;
Aguilar, A.; Bender, P.; Devore, T.; Goldberg, G. V.; Kemper, K. W.;
Lee, S.; Miller, L.; Mitchell, J.; Peplowski, P.; Perry, M.; Reynolds,
R.; Rojas, A.
Bibcode: 2008APS..APRH15002J
Altcode:
The astrophysical significance of the ^14C(?,?) reaction is due
to its involvement in the NCO chain. The NCO chain is thought to
trigger He flashes in white dwarf stars, and is also thought to be
a neutron source for the s-process in low mass stars [L. Buchmann
et al., The Astrophys. Journ. 324 (1988), M. Hashimoto et al., The
Astrophys. Journ. 307 (1986)]. Recently the ANC of the 3^-, 6.4 MeV,
near threshold state in ^18O was measured via a sub-Coulomb, inverse
kinematics ?-transfer reaction at the Florida State University J.D. Fox
Superconducting Accelerator Laboratory. The ^14C(?,?) reaction rate
at stellar temperatures is highly dependent upon the structure of this
3^- state. As shown in E.D. Johnson et al. PRL 97 (2006) the measured
ANC can be used to calculate the ^14C(?,?) reaction rate without any
dependence on nuclear models.
Title: Revised correlation between Odin/OSIRIS PMC properties and
coincident TIMED/SABER mesospheric temperatures
Authors: Feofilov, A.; Petelina, S. V.; Kutepov, A. A.; Pesnell,
W. D.; Goldberg, R. A.; Llewellyn, E. J.; Russell, J. M.
Bibcode: 2006AGUFMSA21A0243F
Altcode:
The Optical Spectrograph and Infrared Imaging System (OSIRIS) instrument
on board the Odin satellite detects Polar Mesospheric Clouds (PMCs)
through the enhancement in the limb-scattered solar radiance. The
Sounding of the Atmosphere using the Broadband Emission Radiometry
(SABER) instrument on board the TIMED satellite is a limb scanning
infrared radiometer that measures temperature and vertical profiles
and energetic parameters for minor constituents in the mesosphere
and lower thermosphere. The combination of OSIRIS and SABER data
has been previously used to statistically derive thermal conditions
for PMC existence [Petelina et al., 2005]. In this work, we employ
the simultaneous common volume measurements of PMCs by OSIRIS and
temperature profiles measured by SABER for the Northern Hemisphere
summers of 2002--2005 and corrected in the polar region by accounting
for the vibrational-vibrational energy exchange among the CO2 isotopes
[Kutepov et al., 2006]. For each coincidence identified within ±1
degree latitude, ±2 degrees longitude and ≤1 hour time the frost
point temperatures were calculated using the corresponding SABER
temperature profile and water vapor densities of 1, 3, and 10 ppmv. We
found that the PMC presence and brightness correlated only with
the temperature threshold that corresponds to the frost point. The
absolute value of the temperature below the frost point, however,
didn't play a significant role in the intensity of PMC signal for the
majority of selected coincidences. The presence of several bright
clouds at temperatures above the frost point is obviously related
to the limitation of the limb geometry when some near- or far-field
PMCs, actually located at higher (and colder) altitudes are detected
at lower altitudes. S.V. Petelina, D.A. Degenstein, E.J. Llewellyn,
N.D. Lloyd, C.J. Mertens, M.G. Mlynczak, and J.M. Russell III, "Thermal
conditions for PMC existence derived from Odin/OSIRIS and TIMED/SABER
data", Geophys. Res. Lett., 32, L17813, doi: 10.1029/2005GL023099,
(2005) A.A. Kutepov, A.G. Feofilov, B.T. Marshall, L.L. Gordley,
W. D. Pesnell, R.A. Goldberg, and J.M. Russell III, "SABER temperature
observations in the summer polar mesosphere and lower thermosphere:
importance of accounting for the CO2 ν_2 quanta V -V exchange",
accepted for publication in Geophys. Res. Lett., (2006)
Title: Annual review of astronomy and astrophysics, Vol. 42.
Authors: Goldberg, Leo
Bibcode: 2004ARA&A..42.....G
Altcode:
No abstract at ADS
Title: Annual review of astronomy and astrophysics, Vol. 41
Authors: Goldberg, Leo
Bibcode: 2003ARA&A..41.....G
Altcode:
No abstract at ADS
Title: A Survey of Proper-Motion Stars. XV. Orbital Solutions for
34 Double-lined Spectroscopic Binaries
Authors: Goldberg, Dorit; Mazeh, Tsevi; Latham, David W.; Stefanik,
Robert P.; Carney, Bruce W.; Laird, John B.
Bibcode: 2002AJ....124.1132G
Altcode:
We present orbital solutions for 34 double-lined spectroscopic binaries
found in the Carney-Latham sample of 1464 stars selected for high
proper motion. We use TODCOR, a two-dimensional correlation technique,
to extract the velocities for the primary and secondary stars and their
light ratio. For our single-order echelle spectra, obtained with the
Center for Astrophysics Digital Speedometers, we find that we can reach
secondaries that are as much as 2 mag fainter than their primaries. The
ratio of the primary to secondary velocity residuals from the orbital
fit equals approximately the secondary-to-primary light ratio, as
would be expected for the photon-limited case. We use our mass and
light ratios to evaluate the mass-luminosity relation for metal-poor
main-sequence dwarfs in the mass range 0.55-0.8 Msolar. We
assume an L~Mβ relation and find that the exponent at around
5200 Å is 7.4+/-0.6. We find this is in good agreement with the slope
of the corresponding theoretical MV-M 14 Gyr isochrones
from the VandenBerg & Bell models for metal-poor stars. Some of
the results presented here used observations made with the Multiple
Mirror Telescope, a facility operated jointly by the University of
Arizona and the Smithsonian Institution.
Title: Phenomenology of Randall-Sundrum black holes
Authors: Anchordoqui, Luis A.; Goldberg, Haim; Shapere, Alfred D.
Bibcode: 2002PhRvD..66b4033A
Altcode: 2002hep.ph....4228A
We explore the phenomenology of microscopic black holes in the
S1/Z2 Randall-Sundrum (RS) model. We consider the
canonical framework in which both gauge and matter fields are confined
to the brane and only gravity spills into the extra dimension. The
model is characterized by two parameters: the mass of the first
massive graviton (m1), and the curvature 1/l of the RS
anti-de Sitter space. We compute the sensitivities of present and
future cosmic ray experiments to black hole mediated events, for a wide
range of l and m1, and compare them with the sensitivities
of Fermilab Tevatron runs I and II to higher-dimensional physics. As
part of our phenomenological analysis, we examine constraints placed
on l by AdS-CFT considerations.
Title: Variation of mesospheric ozone during the highly relativistic
electron event in May 1992 as measured by the High Resolution Doppler
Imager instrument on UARS
Authors: Pesnell, W. Dean; Goldberg, Richard A.; Jackman, Charles H.;
Chenette, D. L.; Gaines, E. E.
Bibcode: 2000JGR...10522943P
Altcode:
Highly relativistic electron precipitation events (HREs) include
long-lived enhancements of the flux of electrons with E>1MeV
into the Earth's atmosphere. HREs also contain increased fluxes of
electrons with energies above 100 keV that have been predicted to
cause large depletions of mesospheric ozone. For some of the measured
instantaneous values of the electron fluxes during the HRE of May
1992, relative depletions greater than 22% were predicted to occur
between altitudes of 55 and 80 km, where HOx reactions
cause local minima in both the ozone number density and mixing ratio
altitude profiles. These ozone depletions should follow the horizontal
distribution of the electron precipitation, having a distinct boundary
equatorward of the L=3 magnetic shell. To search for these effects,
we have analyzed ozone data from the High Resolution Doppler Imager
(HRDI) instrument on UARS. Owing to the multiple, off-track viewing
angles of HRDI, observations in the region affected by the electrons
are taken at similar local solar times before, during, and after the
electron flux increase. Our analysis limits the relative ozone depletion
to values <10% during the very intense May 1992 HRE. We do observe
decreases in the ozone mixing ratio at several points in the diurnal
cycle that may be associated with the transport of water vapor into the
mesosphere during May 1992. This masking of the precipitating electron
effects by the seasonal variations in water vapor can complicate the
detection of those effects.
Title: A Solution to the Problem of the Origin of Biochirality Based
on Observational and Experimental Evidence
Authors: Goldberg, Stanley I.
Bibcode: 2000OLEB...30..212G
Altcode:
The long standing problem of the origin of biochirality (homochirality)
has resisted solution because enantiomers possess identical physical
and chemical properties, so differences upon which to base possible
separations cannot be evoked. While homochirality is an
indispensable factor in contemporary biochemical life, it also
appears to have been required for the emergence of life as well
for two compelling reasons. First, a homochiral prebiotic world
would have neatly avoided the problem of an impossibly large number
of configurational isomers resulting from stereochemically random
assembly of D and L monomers into biopolymers such as peptides. Even
the formation of a peptide of modest size, say one consisting of only
twenty-five amino acid residues, would have meant the stereo-random
formation of 2(exp 25) or 33,554,432 configurationally isomeric
peptides; only one of which would have been the all L-peptide found in
contemporary life. The second reason arises out a number of experimental
and theoretical studies all consistent with the view that the presence
of both enantiomers, even when one form is in low concentration relative
to the other. will prevent or seriously inhibit development of vital
biochemical processes (Bonner, 1995, and refs. therein). Both
difficulties are avoided if enantiopure chiral material were present
on the primitive Earth, and this paper provides such a solution. It
brings together and synthesizes recent observations on the delivery of
nonracemic material to Earth (Cronin and Pizzarello, 1997) with older
experimental work on phase relationships of enantiomers (Jacques et ai,
1981) to reveal how global accumulations of enantiopure biologically
relevant material could have formed on the early Earth.
Title: A search of UARS data for ozone depletions caused by the
highly relativistic electron precipitation events of May 1992
Authors: Pesnell, W. Dean; Goldberg, Richard A.; Jackman, Charles H.;
Chenette, D. L.; Gaines, E. E.
Bibcode: 1999JGR...104..165P
Altcode:
Highly relativistic electron precipitation (HRE) events containing
significant fluxes of electrons with E>1MeV have been predicted
by models to deplete mesospheric ozone. For the electron fluxes
measured during the great HRE of May 1992, depletions were predicted
to occur between altitudes of 55 and 80 km, where HOx
reactions cause a local minimum in the ozone number density and mixing
ratio. Measurements of the precipitating electron fluxes by the particle
environment monitor (PEM) tend to underestimate their intensity; thus
the predictions of ozone depletion should be considered an estimate
of a lower limit. Since the horizontal distribution of the electron
precipitation follows the terrestrial magnetic field, it would show
a distinct boundary equatorward of the L=3 magnetic shell and be
readily distinguished from material that was not affected by the HRE
precipitation. To search for possible ozone depletion effects, we
have analyzed data from the cryogenic limb array etalon spectrometer
and microwave limb sounder instruments on UARS for the above HRE. A
simplified diurnal model is proposed to understand the ozone data from
UARS, also illustrating the limitations of the UARS instruments for
seeing the ozone depletions caused by the HRE events. This diurnal
analysis limits the relative ozone depletion at around 60 km altitude to
values of <10% during the very intense May 1992 event, consistent
with our prediction using an improved Goddard Space Flight Center
two-dimensional model.
Title: Galaxy candidates in the Zone of Avoidance
Authors: Lahav, Ofer; Brosch, Noah; Goldberg, Evgeny; Hau, George
K. T.; Kraan-Korteweg, Renee C.; Loan, Andy J.
Bibcode: 1998MNRAS.299...24L
Altcode: 1997astro.ph..7345L
Motivated by recent discoveries of nearby galaxies in the Zone of
Avoidance (ZOA), we conducted a pilot study of galaxy candidates at
low galactic latitude, near galactic longitude l~135 deg, where the
Supergalactic plane is crossed by the Galactic plane. We observed with
the 1-m Wise Observatory in the l band 17 of the `promising' candidates
identified by visual examination of Palomar red plates by Hau et al. A
few candidates were also observed in R or B bands, or had spectroscopic
observations performed at the Isaac Newton Telescope and at the Wise
Observatory. Our study suggests that there are probably 10 galaxies in
this sample. We also identify a probable planetary nebula. The final
confirmation of the nature of these sources must await the availability
of full spectroscopic information. The success rate of ~50 per cent
in identifying galaxies at galactic latitude |b|<5 deg indicates
that the ZOA is a promising region to discover new galaxies.
Title: Using Astrometry to Deblend Microlensing Events
Authors: Goldberg, David M.
Bibcode: 1998ApJ...498..156G
Altcode: 1997astro.ph..8172G
We discuss the prospect of deblending microlensing events by observing
astrometric shifts of the lensed stars. Since microlensing searches are
generally performed in very crowded fields, it is expected that stars
will be confusion limited rather than limited by photon statistics. By
performing simulations of events in crowded fields, we find that if we
assume a dark lens and that the lensed star obeys a power-law luminosity
function, n(L) ~ L-β, over half the simulated events show a
measurable astrometric shift. Our simulations included 20,000 stars in
a 256 × 256 Nyquist-sampled CCD frame. For β = 2, we found that 58%
of the events were significantly blended (F*/Ftot
<= 0.9), and of those, 73% had a large astrometric shift (>=0.5
pixels). Likewise, for β = 3, we found that 85% of the events were
significantly blended and that 85% of those had large shifts. Moreover,
since the shift may be used to determine the true position of a
source star with respect to the observed point-spread function, a
high-resolution follow-up survey may be used to identify the source
star and determine the blending fraction directly.
Title: Deblending Microlensing Events Using Astrometric Shifts
Authors: Goldberg, D. M.; Wozniak, P.; Paczynski, B.
Bibcode: 1997AAS...191.8307G
Altcode: 1997BAAS...29.1347G
In this poster, we present the prospect that astrometric shifts
can be used to identify blended microlensing events in crowded
fields. Moreover, by measuring an astrometric shift, one can determine
the position of the true lensed star with respect to the local field
with very high precision. We first perform several simulations of
microlensing searches in crowded fields and find that if we assume
a dark lens, and that the lensed star obeys a power law luminosity
function, n(L)~ L(-beta ) , over half the simulated events show a
measurable astrometric shift. For simulations of 20000 stars on a 256x
256 Nyquist sampled CCD frame, we found that with beta =2, 58% of the
events were significantly blended (F_{*}/Ftot <= 0.9),
and of those, 73% had a large astrometric shift (>= 0.5 pixels). For
beta =3, we found that 85% were significantly blended, and that 85%
of those had a significant shift. Since we expect most blended events
to show a significant shift, we look in the OGLE I database (Wozniak
& Szymanski 1997), and find measurable and systematic shifts
in over half the candidate microlensing events, including OGLE # 5,
which was considered to be blended from photometric data.
Title: Optical observations of Dwingeloo 1, a nearby barred spiral
galaxy behind the Milky Way
Authors: Loan, A. J.; Maddox, S. J.; Lahav, O.; Balcells, M.;
Kraan-Korteweg, R. C.; Assendorp, R.; Almoznino, E.; Brosch, N.;
Goldberg, E.; Ofek, E. O.
Bibcode: 1996MNRAS.280..537L
Altcode:
We present new optical observations of the nearby barred spiral
galaxy Dwingeloo 1 (Dw1) obtained with the Isaac Newton, William
Herschel and Wise telescopes. Dw1 lies at Galactic coordinates
(l=138.˚52, b=-0.˚11) and it is heavily obscured by dust and gas in
the Milky Way. We infer that Dw1 is of morphological type SBb or SBc
(T=4), has an inclination i~=50 deg, a position angle PA~=110 deg,
and a recession velocity relative to the Milky Way V_MW=256+/-9 km
s^-1. The measured total apparent magnitudes of Dw1 are V=14.0+/-0.5,
R=12.2+/-0.2 and I=10.7+/-0.2. The extinction estimate towards Dw1 is
highly uncertain. The extinction in the B band, derived from Galactic
HI column density measurements, is A_B~=5.8. Estimated from Galactic
100-μm emission, the extinction is A_B~=4.3, while the reddened
colours of Dw1 yield an estimate of A_B~=10.4. Assuming A_B=5.8,
Tully-Fisher relations in the I and R bands lead to a distance estimate
for Dw1 of D~=300 km s^-1. However, for the derived range of extinction
estimates 4.3<~A_B<~10.4, the distance varies from 100 to 500 km
s^-1. We also report the detection of numerous HII regions associated
with Dw1, and present data from the Infrared Astronomical Satellite
(IRAS) archive.
Title: Annual review of astronomy and astrophysics
Authors: Goldberg, Leo
Bibcode: 1996araa.book.....G
Altcode:
No abstract at ADS
Title: Cataclysmic variables and related objects
Authors: Hack, Margherita; Ladous, Constanze; Jordan, Stuart D.;
Thomas, Richard N.; Goldberg, Leo; Pecker, Jean-Claude
Bibcode: 1993NASSP.507.....H
Altcode: 1993cvro.nasa.....H; 1993QB835.H27......
No abstract at ADS
Title: Rocket measurements of relativistic electrons: New features
in fluxes, spectra and pitch angle distributions
Authors: Herrero, F. A.; Baker, D. N.; Goldberg, R. A.
Bibcode: 1991GeoRL..18.1481H
Altcode:
We report new features of precipitating relativistic electron fluxes
measured on a spinning sounding rocket payload at midday between
altitudes of 70 and 130 km in the auroral region (Poker Flat, Alaska,
65.1°N, 147.5°W, and L=5.5). The sounding rocket (NASA 33.059) was
launched at 21:29 UT on May 13, 1990 during a relativistic electron
enhancement event of modest intensity. Electron fluxes were measured
for a total of about 210 seconds at energies from 0.1 to 3.8 MeV, while
pitch angle was sampled from 0° to 90° every spin cycle. Flux levels
during the initial 90 seconds were about 5 to 8 times higher than in
the next 120 seconds, revealing a time scale of more than 100 seconds
for large amplitude intensity variations. A shorter time scale appeared
for downward electron bursts lasting 10 to 20 seconds. Electrons with
energies below about 0.2 MeV showed isotropic pitch angle distributions
during most of the first 90 seconds of data, while at higher energies
the electrons had highest fluxes near the mirroring angle (90°) when
they occurred, the noted downward bursts were seen at all energies. Data
obtained during the second half of the flight showed little variation
in the shape of the pitch angle distribution for energies greater than
0.5 MeV; the flux at 90° was about 100 times the flux at 0°. We have
compared the low altitude fluxes with those measured at geostationary
orbit (L=6.6), and find that the low altitude fluxes are much higher
than expected from a simple mapping of a pancake distribution at high
altitudes (at the equator). Energy deposition of this modest event
is estimated to increase rapidly above 45 km, already exceeding the
cosmic ray background at 45 km.
Title: Radial Velocity Variations in Alpha Orionis, Alpha Scorpii,
and Alpha Herculis
Authors: Smith, Myron A.; Patten, Brian M.; Goldberg, Leo
Bibcode: 1989AJ.....98.2233S
Altcode:
Radial-velocity observations of Alpha Ori, Alpha Sco A, and Alpha Her A
are used to study radial-velocity periodicities in M supergiants. The
data refer to several metallic lines in the H-alpha region and to
H-alpha itself. It is shown that Alpha Ori and Alpha Sco A have cycle
lengths of about 1 yr and semiamplitudes of 2 km/s. It is suggested
that many semiregular red supergiant varibles such as Alpha Ori may
be heading toward chaos. All three stars show short-term stochastic
flucutations with an amplitude of 1-2 km/s. It is found that the
long-term variability of H-alpha velocities may be a consequence of
intermittent failed ejections.
Title: Baryon-number violation in a quantum gas of W and Higgs bosons
Authors: Goldberg, Haim
Bibcode: 1989PhRvL..62.1952G
Altcode:
Use of a coherent-state representation of the sphaleron allows a direct
calculation of its production rate in a thermal gas of W and Higgs
bosons Technical considerations permit a straightforward calculation
only in the case λ/g2~=1 (MH~=3MW),
where λ is the Higgs-boson quartic coupling, and g is the SU(2) gauge
coupling. For this case it is found that the rate is unsuppressed
for temperatures T>=2.4MW(0), where MW(0)
is the zero-temperature W mass. Thus anomalous B+L violation is also
unsuppressed above this temperature.
Title: FGK stars and T Tauri stars
Authors: Cram, Lawrence E.; Kuhi, Leonard V.; Jordan, Stuart; Thomas,
Richard; Goldberg, Leo; Pecker, Jean-Claude
Bibcode: 1989NASSP.502.....C
Altcode: 1989QB843.C6C73....; 1989fstt.book.....C
The purpose of this book, FGK Stars and T Tauri Stars, like all other
volumes of this series, is to exhibit and describe the best space
data and ground based data currently available, and also to describe
and critically evaluate the status of current theoretical models
and physical mechanisms that have been proposed to interpret these
data. The method for obtaining this book was to collect manuscripts
from competent volunteer authors, and then to collate and edit these
contributions to form a well structured book, which will be distributed
to an international community of research astronomers by NASA and by
the French CNRS.
Title: Atomic spectroscopy and astrophysics
Authors: Goldberg, Leo
Bibcode: 1988PhT....41h..38G
Altcode:
The evolution of atomic spectroscopy as a central part of astrophysics
is reviewed. The beginnings of laboratory astrophysics and the birth
of theoretical astrophysics are examined. The way in which theoretical
physics, including quantum theory, improved the accuracy of astronomical
models, the acceptance of calculations of transition probabilities by
astronomers, and laboratory astrophysics since the end of World War II
are discussed. Several spectra are presented, noting their importance
to astrophysics.
Title: O stars and Wolf-Rayet stars
Authors: Conti, Peter S.; Underhill, Anne B.; Jordan, Stuart; Thomas,
Richard N.; Goldberg, Leo; Pecker, Jean-Claude; Baade, D.; Divan,
L.; Garmany, C. D.; Henrichs, H. F.; Kudritzki, R. P.; Pauldrach,
A.; Prévot-Burnichon, M. -L.; Puls, J.
Bibcode: 1988NASSP.497.....C
Altcode: 1988oswr.book.....C
Basic information is given about O and Wolf-Rayet stars indicating
how these stars are defined and what their chief observable properties
are. Part 2 of the volume discussed four related themes pertaining to
the hottest and most luminous stars. Presented are: an observational
overview of the spectroscopic classification and extrinsic properties
of O and Wolf-Rayet stars; the intrinsic parameters of luminosity,
effective temperature, mass, and composition of the stars, and a
discussion of their viability; stellar wind properties; and the
related issues concerning the efforts of stellar radiation and
wind on the immediate interstellar environment are presented. Contents: Perspective (R. N. Thomas).Part I. Introduction (L. Divan,
M.-L. Prévot-Burnichon).1. Introducing the O and Wolf-Rayet stars.Part
II. One perspective on O, Of, and Wolf-Rayet stars emphasizing winds
and mass loss, with remarks on environment and evolution:2. Overview of
O, Of, and Wolf-Rayet populations (P. S. Conti). 3. Intrinsic stellar
parameters (P. S. Conti, D. Baade). 4. Stellar winds: (a) Introduction
(P. S. Conti). (b) Mass loss from O stars (C. D. Garmany). (c) Mass
loss in Wolf-Rayetstars (P. S. Conti). (d) Radiation-driven winds
of hot luminous stars (R. P. Kudritzki, A. Pauldrach, J. Puls). (e)
Intrinsic variability in ultraviolet spectra of early-type stars: the
discrete absorption lines (H. Henrichs). 5. Environments and evolution
(P. S. Conti).Part III. Another perspective on O, Of, and Wolf-Rayet
stars, emphasizing model atmospheres and possibilities for atmospheric
heating (A. B. Underhill): 6. Understanding the O and Wolf-Rayet
stars. 7. Model Atmospheres and the theory of spectra for O and
Wolf-Rayet stars. 8. The physics of the mantles of hot stars. 9. Summary
of processes influencing the spectra of O and Wolf-Rayet stars.
Title: Radial Velocity Variations of Alpha Orionis (Betelgeuse)
Authors: Patten, B. M.; Smith, M. A.; Goldberg, L.
Bibcode: 1987BAAS...19Q1028P
Altcode: 1987BAAS...19Z1028P
No abstract at ADS
Title: Comments on Solar Wind 6 (edited by S. Drake)
Authors: Goldberg, L.
Bibcode: 1987sowi.conf..695G
Altcode:
No abstract at ADS
Title: Diameter and Limb-darkening Measures for Alpha Orionis
Authors: Cheng, A. Y. S.; Hege, E. K.; Hubbard, E. N.; Goldberg, L.;
Strittmatter, P. A.; Cocke, W. J.
Bibcode: 1986ApJ...309..737C
Altcode:
Previously reported speckle interferometric measurements of the
angular diameter of Alpha Ori are widely scattered and apparently
inconsistent. Stellar atmosphere models predict a stellar disk to be
limb-darkened differently for different spectral features, and that
less limb-darkening will be observed at longer wavelengths. Upon
careful analysis of calibrated speckle observations obtained at
various wavelengths with the KPNO 4 m telescope, a single diameter
parameter is found to be inadequate to explain all of the features of
the measurements. There is evidence for a central stellar component
of 42.1(+ or - 1.1) mas diameter with extended structure surrounding
it. Limb-darkening effects are suggested by attempts to fit cosine
model image profiles to the data. These fits have significant residuals
at large radii suggesting a faint envelope extending from 1 to 5
stellar radii.
Title: Secondary Condensational Instability
Authors: Goldberg, L. P.; Dahlburg, R. B.
Bibcode: 1986BAAS...18..991G
Altcode:
No abstract at ADS
Title: Intermediate-coupling calculation of atomic spectra from
hot plasma
Authors: Goldberg, A.; Rozsnyai, B. F.; Thompson, P.
Bibcode: 1986PhRvA..34..421G
Altcode:
An algorithm is presented for the detailed computation of the spectral
lines in hot, partially ionized plasmas in local thermodynamic
equilibrium. The procedure uses the wave functions and state
probabilities determined from the average atom model for microscopic
configuration accounting. We use intermediate coupling to include the
detailed structure of the bound-bound transition arrays. The model is
applied to bromine plasma under such temperature and density conditions
that partially filled L shells occur.
Title: Mass loss
Authors: Goldberg, Leo
Bibcode: 1986NASSP.492..245G
Altcode: 1986mts..book..245G
Observational evidence for mass loss from cool stars is
reviewed. Spectra line profiles are used for the derivation of mass-loss
rates with the aid of the equation of continuity. This equation implies
steady mass loss with spherical symmetry. Data from binary stars, Mira
variables, and red giants in globular clusters are examined. Silicate
emission is discussed as a useful indicator of mass loss in the middle
infrared spectra. The use of thermal millimeter-wave radiation, Very
Large Array (VLA) measurement of radio emission, and OH/IR masers are
discussed as a tool for mass loss measurement. Evidence for nonsteady
mass loss is also reviewed.
Title: The M-type stars
Authors: Johnson, Hollis Ralph; Querci, Francois R.; Jordan, Stuart;
Thomas, Richard; Goldberg, Leo; Pecker, Jean-Claude
Bibcode: 1986NASSP.492.....J
Altcode: 1986mts..book.....J; 1986QB843.M16M89...
No abstract at ADS
Title: Josif Shklovsky: A Personal Reflection
Authors: Goldberg, Leo
Bibcode: 1985S&T....70..109G
Altcode:
No abstract at ADS
Title: Optical Spectroscopy of Red Giants (Review)
Authors: Goldberg, L.
Bibcode: 1985ASSL..117...21G
Altcode: 1985mlrg.proc...21G
Accomplishments and problems in the study of mass loss from cool stars
in the optical spectrum are reviewed. Accurate mass loss rates remain
elusive principally because of inadequate knowledge of density, velocity
and ionization structure in the circumstellar shells. Improved rates
may be expected from binary star systems. Empirical rates derived for
stars in globular clusters are found to be of doubtful validity. It
is shown that optical observations can furnish important clues to the
understanding of mass loss mechanisms.
Title: Reflections on the solar-stellar connection.
Authors: Goldberg, L.
Bibcode: 1985PASP...97..537G
Altcode:
The achievements of optical astronomy in the investigation of the sun
as a typical star in connection with the study of stellar evolution are
reviewed, with emphasis given to the accomplishments of George Ellery
Hale. Consideration is given to the discovery of magnetic fields on
the sun; measurements of temperatures in the solar corona; and the
early history of observational techniques for high dispersion solar
spectroscopy. The development of satellite based astronomical devices
such as the IUE, the Einstein Observatory, and the Space Telescope, is
also considered. The construction of automatic photoelectric telescopes
(APTs) for observations of variable stars is also discussed.
Title: Mass loss from cool stars.
Authors: Goldberg, L.
Bibcode: 1985fsgf.book..279G
Altcode: 1986fsgf.book..279G
This review discusses (1) empirical determinations of mass loss rates
for highly evolved cool stars, (2) some of the mechanisms that have been
proposed to drive the flow, and (3) some aspects of stellar evolution,
such as the formation of planetary nebulae.
Title: Interpreting Alpha Orionis Speckle Interferometry
Authors: Cheng, A.; Hege, K.; Strittmatter, P.; Goldberg, L.
Bibcode: 1984BAAS...16..939C
Altcode:
No abstract at ADS
Title: Reflections on the solar-stellar connection.
Authors: Goldberg, L.
Bibcode: 1984BAAS...16..874G
Altcode:
No abstract at ADS
Title: The variability of alpha Orionis.
Authors: Goldberg, L.
Bibcode: 1984PASP...96..366G
Altcode:
A survey of variations in the radial-velocity and visual brightness
of the star Betelgeuse (alpha-Orionis) over the last six decades is
presented. On the basis of a comparison of the results of several
observations, it is suggested that major disturbances in Betelgeuse's
atmosphere are likely to occur in the year or two following the minimum
in the six-year velocity curve. A coordinated observing program is
proposed to take place during and after the next minimum, which is
predicted to take place in early 1984. The desirable observations
include multicolor photometry (particularly in the infrared),
polarization measurements, and spectroscopy.
Title: Activity on Betelgeuse
Authors: Goldberg, L.
Bibcode: 1984Mercu..13...82G
Altcode:
No abstract at ADS
Title: Introductory Remarks to the Session on Alpha Orionis and
Related Topics
Authors: Goldberg, L.
Bibcode: 1984LNP...193..333G
Altcode: 1984csss....3..333G
No abstract at ADS
Title: Founding of Kitt Peak
Authors: Goldberg, Leo
Bibcode: 1983S&T....65..228G
Altcode:
No abstract at ADS
Title: Summary of the Colloquium
Authors: Goldberg, L.
Bibcode: 1983ASSL..102..653G
Altcode: 1983IAUCo..71..653G; 1983ards.proc..653G
No abstract at ADS
Title: Remote Observing Origins
Authors: Goldberg, L.
Bibcode: 1983S&T....66..484G
Altcode:
No abstract at ADS
Title: Possible origins for the 12 microns emission lines in the
solar spectrum
Authors: Goldberg, L.
Bibcode: 1983ASSL..102..327G
Altcode: 1983IAUCo..71..327G; 1983ards.proc..327G
The detection of about 40 unidentified emission lines near a
wavelength of 12 microns in the solar spectrum has been reported
by Braut and Noyes (1982, 1983). Braut and Noyes point out that
these lines are a potentially powerful tool for magnetic field
measurements in stars. It appears that the great widths of the
absorption features in the strongest lines offer probably a strong
clue to their identifications. The present investigation is concerned
with two possible sources for the line broadening taking into account
abundance broadening and autoionization.
Title: Prologue - Astronomy before the space age
Authors: Goldberg, L.
Bibcode: 1983ssst.book....1G
Altcode:
Progress in astronomical and astrophysical knowledge since about 1900
is traced, with a focus on the beginnings of space-based observations
in the late 1950's. It is pointed out that observations were almost
exclusively restricted to the visible spectrum unitl 1946. The unique
possibilities offered by space observatories are listed, and the
original plans for space-based studies of the earth, moon, planets,
sun, and interplanetary space, as well as of phenomena beyond the solar
system are reviewed. The direction of future space observations with
the Space Telescope is indicated.
Title: An occultation angular diameter in Half light.
Authors: White, N. M.; Kreidl, T. J.; Goldberg, L.
Bibcode: 1982ApJ...254..670W
Altcode:
The lunar occultation of 119 Tauri, spectral type M2 Ib, was observed
in continuum light and in the light of the Ha absorption line. The
restored strip-brightness distributions indicate that the Ha light
comes from a region having at least twice the diameter of that producing
the continuum light.
Title: Speckle interferometry of alpha Ori: preliminary results.
Authors: Goldberg, L.; Hege, E. K.; Hubbard, E. N.; Strittmatter,
P. A.; Cocke, W. J.
Bibcode: 1982SAOSR.392B.131G
Altcode: 1982csss....2..131G
No abstract at ADS
Title: Introductory Remarks at the Summary Session
Authors: Goldberg, L.
Bibcode: 1982obvf.conf..435G
Altcode:
No abstract at ADS
Title: Reply to BOK - International Personal Contact as a Means for
Enrichment of Science
Authors: Goldberg, L.; Gehrels, T.
Bibcode: 1982S&T....63..445G
Altcode:
No abstract at ADS
Title: P CYG profiles in P Cyg.
Authors: Goldberg, L.
Bibcode: 1981A&A...104L...7G
Altcode:
Attention is given to the proposal made by Underhill (1981) that
two strong emission features near lambda 1306 and lambda 1309 in the
spectrum of P Cygni are the result of dielectronic recombination through
the autoionizing levels 3s3p3d 2F0 of Si II, giving rise to multiplet
UV 13.04. It is found that the lines of this multiplet are closely
blended with resonance lines of O I, Si II, and, to some extent,
N I. It is shown that the observed spectrum may be accounted for by
P Cygni profiles of the resonance lines and that, in the absence of
corroborating qualitative calculations, the dielectronic recombination
hypothesis is unjustified.
Title: Outflow of Matter in the Chromosphere of Alpha-Orionis
Authors: Goldberg, L.
Bibcode: 1981ASSL...89..111G
Altcode: 1981emls.proc..111G; 1981IAUCo..59..111G
No abstract at ADS
Title: Book-Review - Beyond the Atmosphere
Authors: Newell, H. E.; Goldberg, L.
Bibcode: 1981S&T....62..474N
Altcode:
No abstract at ADS
Title: Acceleration of mass flow in the chromosphere of Alpha Orionis
Authors: Goldberg, L.
Bibcode: 1981ASSL...88..301G
Altcode: 1981pprg.work..301G
The spectrum of Alpha Orionis is composite and consists of four
components arising from the photosphere, two distant shells expanding
at constant velocities differing by 6-7 km/s, and a warm chromosphere
in which the mass flow is being accelerated, perhaps to its terminal
value in the inner shell. Calculations are presented on the feasibility
of direct observational determinations of the heights and thicknesses
of the chromospheric regions in bright giants and supergiants, using
the technique of speckle interferometry and lunar occultations
Title: Solar physics
Authors: Goldberg, L.
Bibcode: 1981ssca.proc...14G
Altcode:
The history of U.S. solar exploration is recounted. The state
of knowledge concerning solar physics prior to World War II is
discussed as a background, and the use of V-2 rockets after the war
to penetrate the ozone layer and make observations is described. The
use of Solar-scopes in the post-Sputnik, pre-NASA days, and the
findings made with them, are discussed along with the efforts of the
National Academy of Sciences. Finally, the NASA Orbiting Astronomical
Observatory satellite program is reported on, both its history and
its accomplishments in solar physics. The engineering involved in the
missions is also discussed.
Title: Observations of the Outer Atmospheric Regions of Alpha-Orionis
Authors: Bernat, A. P.; Goldberg, L.
Bibcode: 1980LNP...114..278B
Altcode: 1980sttu.coll..278B; 1980IAUCo..51..278B
No abstract at ADS
Title: Scientific Need for Space Astronomy
Authors: Goldberg, L.
Bibcode: 1980HiA.....5...63G
Altcode:
No abstract at ADS
Title: Complementarity Between Space and Ground-Based Developments:
Overview
Authors: Goldberg, L.
Bibcode: 1980oits.conf..129G
Altcode:
No abstract at ADS
Title: Panel Discussion: Space VS. Ground-Competition or Collaboration
Authors: Goldberg, L.; Gursky, H.; O'dell, C.; Strittmatter, P.;
Wampler, J.; Strom, S.
Bibcode: 1980oits.conf.1151G
Altcode:
No abstract at ADS
Title: Motions in the Atmosphere of Alpha Orionis
Authors: Goldberg, L.; Testerman, L.; Willmarth, D.
Bibcode: 1979BAAS...11..682G
Altcode:
No abstract at ADS
Title: Some problems connected with mass loss in late-type stars
Authors: Goldberg, L.
Bibcode: 1979QJRAS..20..361G
Altcode:
Observational and theoretical evidence for mass loss from various
types of stars are summarized, and mechanisms for its generation
are described, including shock waves, thermally driven winds, and
radiation-driven winds with laminar flow. In particular, spectroscopic
observations of Alpha Orionis are reported, and the K I, Ca II, and H
I lines show that its atmosphere is divided into at least three zones:
a photosphere fluctuating in both brightness and radial velocity, an
expanding chromosphere hot enough (temperature on the order of 1000 K)
to emit strong Balmer-line radiation and uncoupled from motions in the
photosphere, and a cold, distant circumstellar shell. Furthermore,
the 5.781 yr period for the mean radial velocity variation of the
photosphere is found to be correct to within about 0.5%, and the flow
of matter away from the star appears to begin in the chromosphere,
where it is accelerated to about 50% of its terminal value.
Title: Astronomy in China. A trip report of the American Astronomy
Delegation
Authors: Goldberg, Leo; Edward, Lois
Bibcode: 1979actr.book.....G
Altcode:
No abstract at ADS
Title: American Astronomers Visit China II
Authors: Goldberg, Leo
Bibcode: 1978S&T....56..383G
Altcode:
No abstract at ADS
Title: American Astronomers Visit China I
Authors: Goldberg, Leo
Bibcode: 1978S&T....56..279G
Altcode:
No abstract at ADS
Title: Kitt Peak National Observatory, Tucson, Arizona; Cerro Tololo
Inter-American Observatory, La Serena, Chile. Reports.
Authors: Goldberg, L.; Blanco, V.
Bibcode: 1978BAAS...10..152G
Altcode:
No abstract at ADS
Title: Observations of the mid-latitude lower ionosphere in winter
Authors: Aikin, A. C.; Goldberg, R. A.; Jones, W.; Kane, J. A.
Bibcode: 1977JGR....82.1869A
Altcode:
Rocket observations of the lower ionosphere in the winter of 1971 at two
locations show differences of electron density which are attributed to
enhancements of nitric oxide and energetic electron fluxes precipitated
into the mesosphere during the poststorm phase of a geomagnetic
storm. Electron density distributions were observed above Wallops
Island, Virginia, and Keweenaw, Michigan, larger values occurring
at Keweenaw. Energetic electron fluxes were greater at Keweenaw (L =
3.9) than at Wallops Island (L = 2.5). While particle ionization was
the dominant factor in establishing the electron density during one
measurement at Keweenaw, particles were not present 2 days earlier,
even though the electron density distribution was significantly
larger than that observed at Wallops Island on both occasions. An
accompanying ion composition profile measured at Keweenaw during the
earlier flight showed NO+ to be the dominant ion to 76 km,
where the concentration of hydrated ions, H3O+
· (H2O)n, exceeded that of NO+. This
lowering of the transition height from NO+ to hydrated
species is in agreement with independent observations of D region ion
composition during anomalous winter conditions.
Title: Donald Howard Menzel
Authors: Goldberg, Leo
Bibcode: 1977S&T....53..244G
Altcode:
No abstract at ADS
Title: Observations of K I Line Emission in the Circumstellar Shell
of Alpha Orionis.
Authors: Lynds, C. R.; Harvey, J. W.; Goldberg, L.
Bibcode: 1977BAAS....9Q.345L
Altcode:
No abstract at ADS
Title: Kitt Peak National Observatory, Tucson, Arizona; Cerro Tololo
Inter-American Observatory, La Serena, Chile. Observatory reports.
Authors: Goldberg, L.
Bibcode: 1976BAAS....8..129G
Altcode:
No abstract at ADS
Title: High-resolution profiles of sodium and potassium lines in
Alpha Orionis.
Authors: Goldberg, L.; Ramsey, L.; Testerman, L.; Carbon, D.
Bibcode: 1975ApJ...199..427G
Altcode:
Profiles of the K I resonance line at 7698.98 A and of the D1
and D2 lines of Nai in the spectrum of a Ori have been recorded
photoelectrically using the main beam of the McMath solar telescope
at KPNO. The Na lines were observed in the fourth order of the
spectrograph and the K iline in the third order, providing a resolving
power of approximately 50 mA. The observed profiles are consistent with
a model in which radiation from the stellar photo sphere is scattered
and reemitted by an expanding envelope or envelopes of radius large
compared with that of the photosphere. Each blueshifted absorption
core appears to consist of two components of approximately the same
intensity. The first has a heliocentric radial velocity of + 11-13 km ,
which agrees very well with measurements of other resonance lines by
other observers, whereas the second is in the range + 6 km 1 and appears
not to have been detected previously. Subject headings: circumstellar
shells - late-type stars - stellar winds - stars, individual
Title: High Resolution Profiles of Sodium and Potassium Lines in
α Orionis.
Authors: Goldberg, L.; Ramsey, L.; Testerman, L.; Carbon, D.
Bibcode: 1975BAAS....7..233G
Altcode:
No abstract at ADS
Title: Circumstellar shells around cool stars.
Authors: Goldberg, L.
Bibcode: 1975MSRSL...9..387G
Altcode: 1975assp.conf..387G; 1975apes.conf..387G
The study of mass loss from red giants, as revealed by shells of
gas and dust surrounding the stars, is aimed at establishing the
mechanism by which red giants may evolve noncatastrophically to the
white dwarf stage, while at the same time providing a source for the
replenishment of interstellar gas used in star formation. The principal
methods of deriving rates of mass loss from late-type stars, i.e.,
by optical spectroscopy and by measurements of infrared radiation
from circumstellar dust, are summarized and it is suggested that
present estimates of the loss rates may be in error by factors of from
2-10. Some new results, which have recently been obtained at the Kitt
Peak and McDonald Observatories, illustrate the importance of achieving
very high spectroscopic resolution as a basis for understanding the
structure and dynamics of circumstellar shells. New observations of
the profiles of the Na I and K I lines in Alpha Orionis will be shown
as examples.
Title: Synchronous Mode-Locked Dye Lasers for Picosecond Spectroscopy
and Nonlinear Mixing
Authors: Goldberg, L. S.; Moore, C. A.
Bibcode: 1975LNP....43..248G
Altcode: 1975lasp.conf..248G
No abstract at ADS
Title: Research with Solar Satellites
Authors: Goldberg, Leo
Bibcode: 1974ApJ...191....1G
Altcode:
Subject headings: chromospheres, solar - corona, solar - granules
and supergranules, solar - hydromagnetics - magnetic fields, solar -
solar activity - spectroheliograms - Sun - ultraviolet - X-rays
Title: The Harvard Experiment on OSO-6: Instrumentation, Calibration,
Operation, and Description of Observations
Authors: Huber, Martin C. E.; Dupree, A. K.; Goldberg, Leo; Noyes,
R. W.; Parkinson, W. H.; Reeves, E. M.; Withbroe, George L.
Bibcode: 1973ApJ...183..291H
Altcode:
The Harvard experiment carried by OS 0-6 was an extreme-ultraviolet
(EUV) spectrometerspectroheliometer with wavelength range 285-1385 A,
spatial and spectral bandwidth 35 x 35 (arc sec)2 and 3 A, respectively;
the instrumeflt acquired data that have been deposited with the National
Space Science Data Center and World Data Center A at the Goddard Space
Flight Center in Greenbelt, Maryland, and are now available in their
entirety to the scientific community. This paper describes aspects
of the experiment that are relevant to potential users of the data:
instrument configuration and parameters, laboratory and inflight
calibrations, as well as operational capabilities and procedures. We
also report the observations obtained and, where relevant, list
the nature, number, and dates of observations. Subject headings:
atmospheres, solar - instruments - solar activity - spectra, solar -
spectra, ultraviolet
Title: Kitt Peak National Observatory, Tucson, Arizona and Cerro
Tololo Inter-American Observatory, La Serena, Chile. Observatory
reports.
Authors: Goldberg, L.
Bibcode: 1973BAAS....5Q.142G
Altcode:
No abstract at ADS
Title: Kitt Peak National Observatory, Tucson, Arizona; Cerro Tololo
Inter-American Observatory, La Serena, Chile. Observatory reports.
Authors: Goldberg, L.
Bibcode: 1973BAAS....5R.142G
Altcode:
No abstract at ADS
Title: Annual Review of Astronomy and Astrophysics, Vol._11.
Authors: Goldberg, L.; Layzer, D.; Phillips, J. G.
Bibcode: 1973ARA&A..11.....G
Altcode:
No abstract at ADS
Title: HIGH-n Balmer Transitions in Gaseous Nebulae
Authors: Goad, L. E.; Goldberg, L.; Greenstein, Jesse L.
Bibcode: 1972ApJ...175..117G
Altcode:
The intensities of the Balmer lines arising from levels with principal
quantum number n > 15, and the intensity of the apparent continuum
formed by the overlapping of the Balmer lines, have been measured in
the Orion Nebula (NGC 1976) and the planetary nebula NGC 7027. These
observed intensities have been compared with the predictions of
Brocklehurot's recombination theory in order to deduce the electron
temperature and density of the nebulae. We find that % = 8600 +
1500 K and logjo N, = 4.1 + 0.3 for NGC 1976 and that T, = 69000 +
15000 K and logio AT, = 5.6 + 0.3 for NGC 7027.
Title: Harvard College Observatory, Cambridge,
Massachusetts. Observatory report.
Authors: Goldberg, L.
Bibcode: 1972BAAS....4...40G
Altcode:
No abstract at ADS
Title: Infrared and microwave emission from nebulae in the Galaxy.
Authors: Goldberg, L.
Bibcode: 1972saim.conf..315G
Altcode:
No abstract at ADS
Title: Annual Review of Astronomy and Astrophysics, Vol._10.
Authors: Goldberg, L.; Layzer, D.; Phillips, J. G.
Bibcode: 1972ARA&A..10.....G
Altcode:
No abstract at ADS
Title: Coronal Electron Density Maps for 7 March, 1970, Derived from
Mgx λ625 Spectroheliograms (Papers presented at the Proceedings
of the International Symposium on the 1970 Solar Eclipse, held in
Seattle, U. S. A. , 18-21 June, 1971.)
Authors: Withbroe, G. L.; Dupree, A. K.; Goldberg, L.; Huber,
M. C. E. .; Noyes, R. W.; Parkinson, W. H.; Reeves, E. M.
Bibcode: 1971SoPh...21..272W
Altcode:
We have analyzed daily Mgx λ 625 spectroheliograms acquired by the
Harvard College Observatory experiment on OSO-6 for a 28-day period
centered on 7 March, 1970, the date of a well-observed total solar
eclipse. These data are used to construct maps of the variation across
the solar disk of the electron density at the base of the corona. The
correspondence of high and low density regions with regions of enhanced
and reduced emission in white light and Mgx pictures made during or
near the time of the eclipse are described.
Title: Rocket Observations of the Ultraviolet Solar Spectrum during
the Total Eclipse of 1970 March 7
Authors: Gabriel, A. H.; Garton, W. R. S.; Goldberg, L.; Jones,
T. J. L.; Jordan, Carole; Morgan, F. J.; Nicholls, R. W.; Parkinson,
W. J.; Paxton, H. J. B.; Reeves, E. M.; Shenton, C. B.; Speer, R. J.;
Wilson, R.
Bibcode: 1971ApJ...169..595G
Altcode:
A sequence of thirty-five ultraviolet photographic spectra of the
Sun has been obtained in the wavelength region 850-2190 A, as a
function of time during the eclipse. These cover the range from before
second contact until midtotality, with a spatial resolution of the
order 2 arc sec. A general description of the experiment and data is
given. Twenty-five new coronal lines have been seen, the majority of
which have been identified as new forbidden transitions. The La corona
is observed out to over 1.5 R0, and a quantitative interpretation
is presented. Analyses of other features-e.g., prominences,
quiet-atmosphere structure, and coronal condensations-are continuing.
Title: Radio Recombination Lines
Authors: Goldberg, Leo
Bibcode: 1971spas.conf..169G
Altcode:
No abstract at ADS
Title: Balmer line intensities near the series limit in gaseous
nebulae.
Authors: Goad, L. E.; Goldberg, L.; Greenstein, J. L.
Bibcode: 1971BAAS....3..417G
Altcode:
No abstract at ADS
Title: In Retrospect
Authors: Goldberg, Leo
Bibcode: 1971dngp.conf..147G
Altcode:
No abstract at ADS
Title: Atoms, stars, and nebulae
Authors: Aller, Lawrence Hugh; Goldberg, Leo
Bibcode: 1971asn..book.....A
Altcode: 1971QB461.A568.....
No abstract at ADS
Title: Harvard College Observatory, Cambridge, Massachusetts. Report
1969-1970.
Authors: Goldberg, L.
Bibcode: 1971BAAS....3...78G
Altcode:
No abstract at ADS
Title: The interpretation of XUV solar radiation.
Authors: Goldberg, L.
Bibcode: 1971adiu.conf..476G
Altcode:
No abstract at ADS
Title: The Interpretation of XUV Solar Radiation
Authors: Goldberg, L.
Bibcode: 1971HiA.....2..476G
Altcode:
No abstract at ADS
Title: Annual Review of Astronomy and Astrophysics, Vol.9.
Authors: Goldberg, L.; Layzer, D.; Phillips, J. G.
Bibcode: 1971ARA&A...9.....G
Altcode:
No abstract at ADS
Title: Summary
Authors: Goldberg, L.
Bibcode: 1971ASSL...27..333G
Altcode: 1971psc..conf..333G
No abstract at ADS
Title: Detection and Identification of Recombination Lines from an
H i Region
Authors: Ball, J. A.; Cesarsky, D.; Dupree, A. K.; Goldberg, L.;
Lilley, A. E.
Bibcode: 1970ApJ...162L..25B
Altcode:
The H157a line arising from an H I region has been observed in the
spectrum of NGC 2024 (Orion B). The measured frequency separation
between this line and the anomalous line at 157a allows a firm
identification of the anomalous emitter as carbon. The fraction of
ionized hydrogen in this H I cloud is found to be (2.7 i 1.8) x 1O .
Title: The Analysis of Microwave Recombination Lines
Authors: Goldberg, L.; Cesarsky, D.
Bibcode: 1970ApL.....6...93G
Altcode:
No abstract at ADS
Title: OSO-VI: Surges, Flares, and the Development of Active Regions
Authors: Reeves, E. M.; Dupree, A. K.; Goldberg, L.; Huber, M. C. E.;
Noyes, R. W.; Parkinson, W. H.; Withbroe, G. L.
Bibcode: 1970BAAS....2R.215R
Altcode:
No abstract at ADS
Title: OSO-VI: The EUV Spectrum of Solar-Active Regions
Authors: Dupree, A. K.; Goldberg, L.; Huber, M. C. E.; Noyes, R. W.;
Parkinson, W. H.; Reeves, E. M.; Withbroe, G. L.
Bibcode: 1970BAAS....2..191D
Altcode:
No abstract at ADS
Title: OSO-VI: The Harvard Experiment
Authors: Huber, M. C. E.; Dupree, A. K.; Goldberg, L.; Noyes, R. W.;
Parkinson, W. H.; Reeves, E. M.; Withbroe, G. L.
Bibcode: 1970BAAS....2S.200H
Altcode:
No abstract at ADS
Title: Harvard College Observatory, Cambridge, Massachusetts. Report
1968-1969.
Authors: Goldberg, L.
Bibcode: 1970BAAS....2...43G
Altcode:
No abstract at ADS
Title: Recombination Lines in NGC 7027
Authors: Goldberg, L.
Bibcode: 1970ApL.....5..151G
Altcode:
No abstract at ADS
Title: Annual Review of Astronomy and Astrophysics.
Authors: Goldberg, L.; Layzer, D.; Phillips, J. G.
Bibcode: 1970ARA&A...8.....G
Altcode:
No abstract at ADS
Title: Radiofrequency Recombination Lines
Authors: Dupree, A. K.; Goldberg, Leo
Bibcode: 1970ARA&A...8..231D
Altcode:
No abstract at ADS
Title: Stimulated Emission of Recombination Lines in H i Regions
Authors: Dupree, A. K.; Goldberg, Leo
Bibcode: 1969ApJ...158L..49D
Altcode:
Radio-frequency recombination lines arising from ionized atoms in
H i regions can have intensities which are greatly strengthened
over their equilibrium values as a result of stimulated emission
due to a background continuum. It is suggested that the "anomalous"
recombination line is formed in this way. In addition, hydrogen and
helium recombination lines from H ii regions are expected to have
components formed in H i clouds. Recombination lines may also be
observable from H i clouds that are in the line of sight to nonthermal
continuum sources. Such lines can be used to give a direct measure of
the degree of ionization and abundances in the interstellar medium
Title: Absorption and Emission of Recombination Radiation by H
I Regions
Authors: Dupree, A. K.; Goldberg, Leo
Bibcode: 1969BAAS....1..340D
Altcode:
No abstract at ADS
Title: Ultraviolet Astronomy
Authors: Goldberg, Leo
Bibcode: 1969SciAm.220f..92G
Altcode: 1969SciAm.220...92G
No abstract at ADS
Title: 28.The Infrared Emission of Planetary Nebulae
Authors: Goldberg, L.
Bibcode: 1969LIACo..15..283G
Altcode: 1969MSRSL..17..283G
No abstract at ADS
Title: Harvard College Observatory, Cambridge, Massachusetts. Report
1967-1968.
Authors: Goldberg, L.
Bibcode: 1969BAAS....1...20G
Altcode:
No abstract at ADS
Title: Ultraviolet Solar Images from Space
Authors: Goldberg, Leo; Noyes, Robert W.; Parkinson, William H.;
Reeves, Edmond M.; Withbroe, George L.
Bibcode: 1968Sci...162...95G
Altcode:
No abstract at ADS
Title: Erratum: Stimulated Emission of Radio-Frequency Lines of
Hydrogen
Authors: Goldberg, Leo
Bibcode: 1968ApJ...151..804G
Altcode:
No abstract at ADS
Title: A Description of the Harvard Experiment on OSO-IV
Authors: Reeves, E. M.; Goldberg, L.; Parkinson, W. H.
Bibcode: 1968AJS....73S..74R
Altcode:
The recent Orbiting Solar Observatory, OSO-I V, contained
a photoelectric spectrometer-spectroheliometer in the pointed
section. The instrument has recorded the solar spectrum from a region
of 1 min of arc at the center of the solar disk over the wavelength
region XX 300-1400. The spectrometer can select any single wavelength
in the above range and, using the raster mode of the satellite,
construct a spectroheliogram with a resolution of 1 min of arc. The
optical system, calibration, and operation will be described with
representative samples of data. A unique "quick-look" system has been
used which allows the experimenter to receive an entire orbit's data
in Cambridge within a few minutes and to respond with revised command
sequences on an orbit-by-orbit basis for six consecutive satellite
passes per day. The operational mode of the instrument can thus be
adjusted to take full advantage of current activity on the solar disk.
Title: Buchbesprechungen über: Annual Review of Astronomy and
Astrophysics. (Ed. L. GOLDBERG, D. LAYZER, and J. G. PHILLIPS)
(Ref. A. UNSÖLD)
Authors: Goldberg, L.; Layzer, D.; Phillips, J. G.
Bibcode: 1968ZA.....68..167G
Altcode:
No abstract at ADS
Title: Predicted Infrared Line Spectrum of NGC 7027.
Authors: Goldberg, Leo
Bibcode: 1968AJS....73R.178G
Altcode:
The strong infrared emission observed in the spectra of NGC 7027 and
other objects makes it important to investigate possible sources of
line emission in the spectral region 1Oi3~lOi4 Hz. Delmer, Gould, and
Ramsey (1967) have calculated the expected intensities of magnetic
dipole transitions between fine-structure levels of the ground
terms of p-electron configurations. In this paper we estimate the
intensities both of similar transitions in d-electron configurations
and of recombination lines of hydrogen. The strongest lines in the
d-electron group are those of [Fe v~, [Fe YI~, and [Fe YIIJ, which
also show lines in the visible spectrum.
Title: Observations Astronorniques au-dehors de 1'Atmosphère
Terrestre (Astronomical Observations from outside the Terrestrial
Atmosphere)
Authors: Goldberg, L.
Bibcode: 1968IAUTB..13..215G
Altcode:
No abstract at ADS
Title: Buchbesprechungen über: Annual Review of Astronomy and
Astrophysics. (Ed. L. GOLDBERG, D. LAYZER, and J. G. PHILLIPS)
(Ref. A. UNSÖLD)
Authors: Goldberg, L.; Layzer, D.; Phillips, J. G.
Bibcode: 1968ZA.....69..385G
Altcode:
No abstract at ADS
Title: The Infrared Emission of NGC 7027
Authors: Goldberg, L.
Bibcode: 1968ApL.....2..101G
Altcode:
No abstract at ADS
Title: Theoretical intensities of recombination lines.
Authors: Goldberg, L.
Bibcode: 1968tirl.book.....G
Altcode:
No abstract at ADS
Title: Preliminary EUV Spectroheliograms from OSO-IV
Authors: Noyes, R. W.; Goldberg, L.; Parkinson, W. H.; Reeves, E. M.;
Withbroe, G. L.
Bibcode: 1968AJS....73R..73N
Altcode:
The Harvard OSO-I V spectrometer-spectroheliometer has provided pictures
of the sun over a wide range of wavelengths originating from different
heights in the solar atmosphere, from the low chromosphere through the
corona. Lines from H I through Si XII have been observed against the
solar disk showing structure on the disk both in active regions and, in
certain cases, well above the limb. The data allow a close comparison
with simultaneous ground-based coronal observations. Representative
spectroheliograms in lines of increasing ionization potentials are
used to illustrate the size, structure, and development of active
regions on the limb and on the disk at different heights in the solar
atmosphere. Preliminary observations of limb brightening, instensity
of active regions, and flare activity are presented.
Title: Theoretical Intensities of Recombination Lines
Authors: Goldberg, Leo
Bibcode: 1968iih..conf..373G
Altcode:
No abstract at ADS
Title: Population of Atomic Levels by Dielectronic Recombination
Authors: Goldberg, Leo; Dupree, Andrea K.
Bibcode: 1967Natur.215...41G
Altcode:
IN the preceding communication, Palmer et al. have reported the
observation of an emission line close to the expected position of the
recombination line 109α of C I in the radiofrequency spectra of the
ionized hydrogen regions NGC 2024 and IC 1795. The total intensity of
the newly observed line is about 3 per cent that of the neighbouring
109α line of H I. Let us assume that the two lines originate from the
same volume of space. If the upper levels of C I and H I were populated
in thermodynamic equilibrium, the relative intensities of the two lines
would be roughly in the ratio of the numbers of hydrogen and carbon
ions in the emitting volume. This ratio would be equivalent to that
of the cosmic abundances of hydrogen and carbon if both atoms were
entirely in the singly ionized condition. In the Sun, the abundance
of carbon is 5 × 10-4 of that of hydrogen1,
and there is no reason to suppose that the ratio is greatly different
in H II regions. Thus, if the line found by Palmer et al. is indeed
the 109α line of C I, its observed intensity relative to that of the
same transition in hydrogen is at least sixty times greater than would
be expected from the two assumptions of thermodynamic equilibrium and
normal cosmic abundances. In this communication we point out that the
apparently anomalous overpopulation of the n = 110 level of C I can be
explained as a result of departures from thermodynamic equilibrium,
which result in the preferential population of levels of high total
quantum number by dielectronic recombination.
Title: Solar Abundance Determination from Ultraviolet Emission Lines
Authors: Dupree, Andrea K.; Goldberg, Leo
Bibcode: 1967SoPh....1..229D
Altcode:
The intensities of far ultraviolet emission lines from the solar corona
are analyzed to determine relative coronal abundances for oxygen,
silicon, and iron. Dielectronic recombination is included in the
formulation of ionization equilibrium. Observations of solar radio
emission are used to obtain abundances relative to hydrogen. The
absolute coronal abundances appear to be in agreement with their
respective photospheric values. General properties of the structure of
the chromosphere and corona are deduced from the analysis of observed
emission in the ultraviolet and radio wavelength regions.
Title: Space Solar Physics
Authors: Goldberg, L.
Bibcode: 1967sp...conf..493G
Altcode:
No abstract at ADS
Title: Ultraviolet and X Rays from the Sun
Authors: Goldberg, Leo
Bibcode: 1967ARA&A...5..279G
Altcode:
No abstract at ADS
Title: Population of Atomic Levels by Dielectronic Recombination.
Authors: Goldberg, Leo; Dupree, Andrea K.
Bibcode: 1967AJ.....72Q.799G
Altcode:
Under conditions found in H II regions, the populations of excited
levels of atoms are determined primarily by the balance between
electronic recombination and cascade into the levels and spontaneous
transitions out of them. The bare nucleus of a hydrogenic ion can
combine only by radiative capture but an ion that has one or more
electrons can capture an electron by dielectronic recombination. This
process may occur at a much faster rate and with a wholly different
dependence on n and 1 than that of radiative capture. Illustrative
calculations have been performed for Ca I in which the levels are
assumed to be populated by dielectronic and three-body recombination
and cascade, and to be depopulated by spontaneous downward transitions
and collisional ionization. The results show that (1) the capture
of electrons by dielectronic recombination can greatly increase the
populations of highly excited levels as compared with their equilibrium
values; (2) there will be a value of the total quantum number n for
which bn, the ratio of the actual population to that in thermodynamic
equilibrium, has a maximum value. This maximum occurs at n~50 to 100
for Ne=104 cm-3 and at n~100 to 200 for Ne=102 cm-3 (3) recombination
lines from complex atoms should be found in emission and, with the
appropriate conditions, in absorption.
Title: On the Infrared Continuum of the Sun and Stars
Authors: Noyes, Robert W.; Gingerich, Owen; Goldberg, Leo
Bibcode: 1966ApJ...145..344N
Altcode:
No abstract at ADS
Title: Stimulated Emission of Radio-Frequency Lines of Hydrogen
Authors: Goldberg, Leo
Bibcode: 1966ApJ...144.1225G
Altcode:
No abstract at ADS
Title: Astrophysical Implications of Autoionization
Authors: Goldberg, Leo
Bibcode: 1966aatl.conf....1G
Altcode:
No abstract at ADS
Title: The Sun and Solar Physics
Authors: Goldberg, Leo
Bibcode: 1966aes..conf....3G
Altcode:
No abstract at ADS
Title: Buchbesprechungen über: Annual Review of Astronomy and
Astrophysics. Vol. 3. (Ed. GOLDBERG, L. , A. J. DEUTSCH und D. LAYZER)
(Ref. A. UNSÖLD)
Authors: Goldberg, L.; Deutsch, A. J.; Layzer, D.
Bibcode: 1966ZA.....64..370G
Altcode:
No abstract at ADS
Title: Observations Astronomiques au-dehors de l'Atmosphère Terrestre
(Astronomical Observations from outside the Terrestrial Atmosphere)
Authors: Goldberg, L.
Bibcode: 1966IAUTB..12..371G
Altcode:
No abstract at ADS
Title: Observational Requirements for a Theory of Formation of H
and K Lines
Authors: Goldberg, L.
Bibcode: 1965SAOSR.174..389G
Altcode:
No abstract at ADS
Title: Carbon Monoxide in the Ultraviolet Solar Spectrum.
Authors: Goldberg, L.; Parkinson, W. H.; Reeves, E. M.
Bibcode: 1965ApJ...141.1293G
Altcode:
No abstract at ADS
Title: Collisional excitation of autoionizing levels
Authors: Goldberg, L.; Dupree, A. K.; Allen, J. W.
Bibcode: 1965AnAp...28..589G
Altcode:
No abstract at ADS
Title: A Study of Broad Absorption Features in the Solar Spectrum.
Authors: Goldberg, Leo; Newsom, Gerald; Parkinson, W. H.; Reeves, E. M.
Bibcode: 1965AJ.....70R.676G
Altcode:
The broad depressions (2.6 A wide) in the solar spectrum at X
6362 and 6343 have recently been identified (Mitchell and Mohler,
Astrophys. J. 141, 1126, 1965) as the auto-ionizing transitions 3d4p
3F0 -3d4d 3G in neutral calcium. A shock tube was used to determine the
gf values of these lines and preliminary values have been derived. The
McMath Solar Telescope at the Kift Peak National Observatory was used to
observe these lines and to search for other broad absorptions. At the
center of the disk, the depressions for the 6362 and 6343 A lines were
4.3~0.1% and 2.8*0.2%, respectively, while near the limb (~=0.2) the
percentage depression decreased by 17%. Spectra of cool, highluminosity
stars, kindly loaned by Mount Wilson and Palomar Observatories, also
showed these auto-ionizing lines. Several other broad depressions
which have been observed in the sun are discussed.
Title: Simultaneous Shock Tube Measurements of Fe and CR F values
of Astronomical Interest.
Authors: Goldberg, Leo; Huber, Martin; Parkinson, W. H.; Reeves,
E. M.; Tobey, F. L.
Bibcode: 1965AJ.....70Q.676G
Altcode:
Measurements of relative f values of selected iron and chromium lines
have been made in the wavelength range 3200 to 3800 A. Line strengths
were measured photographically by absorption through the region
behind a reflected shock in a pressure-driven shock tube with a wide
spectrograph slit. Temperatures were determined from the brightness
and emissivity of the shocked gas. Low concentrations of iron and
chromium were introduced together as carbonyls, premixed with the
argon test gas. This was done to ensure the equal processing of both
atoms and to reduce systematic errors in the ratios of oscillator
strengths of the two elements. Populations of the absorbing levels
were determined from the Saha-Boltzmann equation, the hydrodynamic
equations and the charge neutrality condition. The experimental
uncertainties are 15% or better. The f value ratios obtained agree
within a factor of 2 with ratios computed from literature f values
adapted to a common scale (Corliss, C. H., and Bozmann, W. R.,
Natl. Bur. Stds. Monograph 53, 1962, for Cr; Corliss, C. H., and
Warner, B., Astrophys. J. Suppl. No. 83, 1964 for Fe). The technique
of simultaneous measurements of relative f values yields consistent
oscillator strengths for two elements and provides data for an accurate
relative abundance determination.
Title: Collisional excitation of auto-ionizing levels
Authors: Goldberg, L.; Dupree, A. K.; Allen, J. W.
Bibcode: 1965IAUS...23..125G
Altcode:
No abstract at ADS
Title: The Abundance of Iron in the Solar Photosphere.
Authors: Goldberg, Leo; Kopp, Roger A.; Dupree, Andrea K.
Bibcode: 1964ApJ...140..707G
Altcode:
New laboratory measurements of the absolute f-values of Fe 1 lines by
Corliss and Warner (1964) have made possible a new determination of
the abundance of iron in the solar photosphere. Of the 628 lines used
to obtain the curve of growth by the method of weighting functions,
the majority fall on the linear branch of the curve and have lower
excitation potentials in the range 3-5 eV. Since their mean optical
depths of formation are as large as 0.6, it seems unlikely that the
lines are significantly affected by departures from LTE. The resulting
abundances appear to be independent of excitation potential, but seem
to increase slightly with increasing wavelength. The average value
of the derived abundance, log NF,/NH + 12 00 = 6.64, is in very good
agreement with other modern determinations.
Title: The Origin of the Emission Reversals in the Fraunhofer h-
and K-Lines
Authors: Goldberg, Leo
Bibcode: 1964ApJ...140..384G
Altcode:
No abstract at ADS
Title: Origin of Emission Cores in Lines of Ionized Calcium and
Magnesium.
Authors: Goldberg, Leo; Noyes, Robert W.
Bibcode: 1964AJ.....69R.542G
Altcode:
Transitions between doubly excited 4pnl levels and singly excited 4snl
levels of the Ca I atom are shown to be probable contributors to the
emission cores of the Ca II H and K lines in the solar spectrum. The
contribution to the source function from this process is calculated
and found to reach a maximum at a height of approximately 300 km
above the photosphere. Preliminary calculations of line profiles and
center-to-limb variations for the H and K lines of both Ca II and Mg
ii are presented and discussed.
Title: Preliminary Results from a Rocket Flight of the Harvard
OSO-B Spectrometer.
Authors: Goldberg, Leo; Parkinson, W. H.; Reeves, E. M.; Noyes, R. W.
Bibcode: 1964AJ.....69Q.140G
Altcode:
A model of the Harvard OSO-B spectrometer was flown in an Aerobee-Hi
rocket from White Sands, New Mexico on 6 September 1963. During the
course of the rocket flight, which attained a peak altitude of 221 km,
three full scans and part of a fourth were obtained in the spectral
region 1350-500 A. The dimensions of the entrance slit were 1.8 arc
minutes wide by 9.0 arc minutes long. Examination of Ha and Ca K
spectroheliograms shows that the entrance aperture was free of plage
regions. The purpose of the flight was primarily to check the absolute
calibration prior to launch of a similar instrument in OSO-B and also
to obtain data on spectral intensities for the center of the quiet
sun. Essentially all emission lines found by other experimenters were
observed and good records were also obtained of the Lyman continuum. In
general, the observed numbers of counts recorded for the emission lines
are in satisfactory agreement with those predicted on the basis of
published data on photon fluxes and the absolute laboratory calibration,
but there are interesting differences which can be attributed at least
in part to the fact that the present observations refer to the center of
the quiet sun, whereas H interegger `s observations, for example, apply
to the integrated flux from the whole sun, including active regions.
Title: The Abundance of He3 in the Sun.
Authors: Goldberg, Leo
Bibcode: 1962ApJ...136.1154G
Altcode:
No abstract at ADS
Title: Stellar and Interstellar Observations
Authors: Goldberg, Leo
Bibcode: 1962saa..conf..203G
Altcode:
No abstract at ADS
Title: Means of Observation
Authors: Goldberg, Leo
Bibcode: 1962sgba.book...19G
Altcode:
No abstract at ADS
Title: Scientific discussion
Authors: Goldberg, L.
Bibcode: 1962IAUTB..11..194G
Altcode:
No abstract at ADS
Title: Project West Ford-Properties and Analyses: Introduction
Authors: Goldberg, Leo
Bibcode: 1961AJ.....66..105G
Altcode:
No abstract at ADS
Title: The Sun
Authors: Goldberg, Leo; Dyer, E. R., Jr.
Bibcode: 1961sis..book..307G
Altcode:
No abstract at ADS
Title: Galactic and Extragalactic Astronomy
Authors: Goldberg, Leo; Dyer, E. R., Jr.
Bibcode: 1961sis..book..341G
Altcode:
No abstract at ADS
Title: Solar Experiements - U. S. Plans. Report
Authors: Goldberg, Leo
Bibcode: 1961LIACo..10...30G
Altcode: 1961LIACo..10...26G; 1961MSRSL...4...26G
No abstract at ADS
Title: The Abundances of the Elements in the Solar Atmosphere.
Authors: Goldberg, Leo; Muller, Edith A.; Aller, Lawrence H.
Bibcode: 1960ApJS....5....1G
Altcode:
The method of weighting functions has been utilized to derive the
abundances of forty-two elements from faint and medium-strong lines
in the solar spectrum. The model atmosphere adopted is that of Aller
and Pierce as extended by Elste to both higher and deeper layers. The
chief sources of equivalent widths were the measurements by Allen and by
the Utrecht astronomers, but a substantial number of new measurements
were included from McMath-Hulbert Observatory data. TheJ-values were
taken from many different sources, but, whenever possible, experimental
measurements were employed. When laboratory data were not available,
they were replaced by theoretical values based on the assumption of LS
coupling and making use of the f-sum rule or of the Bates and Damgaard
tables for the absolute scale factor. A detailed description is given
of the derivation of the abundance of each element, including the major
sources of uncertainty, such as the errors in the measurement of weak
lines throughout the spectrum and of all lines in the ultraviolet
region, uncertainties in the solar model for ultraviolet lines, and
the unreliable character of many of the f-values employed.
Title: The Measutement of the Local Doppler Shift of Fraunhofer Lines.
Authors: Goldberg, Leo; Mohler, Orren C.; Unno, Wasaburo; Brown,
Jacqueline
Bibcode: 1960ApJ...132..184G
Altcode:
Well-defined spectra showing the Doppler shift arising from
small-scale motions in the solar atmosphere were obtained with the
vacuum spectrograph of the McMath-Hulbert Observatory during August
and September, 1955. These spectra have been measured, and the local
Doppler shifts of several solar absorption lines have been determined
at various positions on the disk of the sun. The average value of the
random turbulent velocity is found to be 0.33 km/sec for elements with
an average diameter of 5.5 seconds of arc (4000 km). However, the values
of the random turbulent velocity, as well as other characteristics,
show systematic differences between weak and strong lines. Metallic
lines formed at average effective optical depths, r(SO0O) larger than
0.2, show smaller velocities than the average. Their r.m.s. velocities
monotonically increase toward the limb of the sun (1.0> >
0.6). Stronger lines (roooo <0.2) show systematically larger
values of the r.m.s. velocities with no appreciable center-to-limb
variation. Near the limb of the sun ( = 0.35) all the measured lines
show smaller r.m.s. velocities than at j# = 0.58. This may be caused
by the lack of resolution of small elements in the neighborhood of the
solar limb. These results suggest that the large-scale motion in the
upper photosphere decreases as the limb of the sun is approached. They
also suggest that a rising element of the atmosphere is statistically
followed by a falling element in the same region.
Title: Solar experiments
Authors: Goldberg, Leo
Bibcode: 1960AJ.....65..274G
Altcode:
Owing to the well-known negative temperature gradient in the It is also
hoped that some type of x-ray imaging device will be solar atmosphere,
the solar chromosphere and corona emit strongly flown in the first
vehicle. in the far-ultraviolet and x-ray regions of the spectrum,
as has Plans are also being developed for the installation of a small
already been revealed by observations from rockets. The highly solar
observatory with a variety of instruments totaling about energetic
events connected with solar flares also result in strong 600 or 700
lb, exclusive of stabilization gear, power supply and emissions at
very short wavelengths. Hence, solar experiments storage, etc. The
instruments would include a high-dispersion from satellites will have
high priority in the astronomy space spectrometer operating in the
region from 3000 to 75 A, one or program. more spectroheliometers to
register images of the sun in Lyman-a Design work has been begun on
the development of solar in- and other monochromatic radiations, an
x-ray telescope and strumentation to be flown in a series of vehicles
with progressively spectrometer, and equipment for the observation
of low-frequency larger payloads. The first experiment is being
designed for a ve- radio emission from the sun. hicle that can carry
instruments up to a weight of about 100 lb Finally, it is pointed out
that a number of important problems and that will be stabilized with a
pointing accuracy of a few min- in solar physics can be solved better by
observations from balloons utes of arc. Two scanning spectrometers will
be employed, one rather than from satellites. These include studies
of the hydro- covering the spectral region from 1600 to 500 A and
the other dynamic and magnetic properties of the solar photosphere,
and from 600 to 75 A. The resolving power would be about 1 A, and
observation of the infrared solar spectrum. the spectrometers would
have a combined weight of about 45 lb.
Title: Astronomy from Satellites and Space Vehicles
Authors: Goldberg, Leo
Bibcode: 1960exsp.conf..119G
Altcode:
No abstract at ADS
Title: Astronomy from Satellites and Space Vehicles
Authors: Goldberg, Leo
Bibcode: 1959JGR....64.1765G
Altcode:
Space experiments of interest to astronomy fall naturally into
three groups. First, the elimination of the earth's atmosphere as
a barrier to observation exposes to view the entire electromagnetic
spectrum of radiation from extraterrestrial sources. It also permits
the investigation both of the faint outer extensions of the solar
atmosphere, which are now obliterated by the bright daylight sky,
and of the weak radiations from faint stars and nebulas which are
masked by radiation from atoms and molecules in the earth's upper
atmosphere. Second, the advent of satellites and space vehicles
makes possible a whole series of experiments and observations which
are absolutely unique and which can test the foundations of physical
theories.
Title: The Photosphere of the Sun.
Authors: Goldberg, Leo; Pierce, A. Keith
Bibcode: 1959HDP....52....1G
Altcode:
The continuous spectrum Solar constant Observed limb darkening Observed
solar energy distribution Observational models of the photosphere The
Fraunhofer spectrum Observational data The formation of Fraunhofer
lines The analysis of Fraunhofer lines General references
Title: The Double Reversal in the Cores of the Fraunhofer H and
K Lines.
Authors: Goldberg, Leo; Mohler, O. C.; Müller, Edith A.
Bibcode: 1959ApJ...129..119G
Altcode:
Observations are presented of the profiles of the central doubly
reversed cores of the H and K lines of Ca ii in the Fraunhofer
spectrum. The profiles were obtained photoelectrically with the
vacuum spectograph of the McMath-Hulbert Observatory at five different
points on the solar disk from M = 1.0 to = 0.2. At the center of the
disk the central intensities of H and K are 2.95 and 2.36 per cent,
respectively, in terms of the neighboring continuous spectrum near
X 4000. At = 0.2 the central intensities are 2.41 and 2.01 per cent
for H and K, respectively, also with reference to the continuum at
X 4000 at the center of the disk. The relative intensity ratio H:
K is found to be constant in the inner absorption core and nearly
the same for all values of . This suggests that the logarithm of
the source function varies linearly with the logarithm of Nh, the
number of Ca ii atoms per square centimeter above height, h, in the
chromosphere. The Doppler widths were derived by two methods, namely,
(1) by an intercomparison method which is independent of the source
functiop and (2) by using the depth-dependence of the source function
and the shapes of the profiles. The Doppler widths thus found increase
from 0.063 A at = 1.0 to 0.110 A at = 0.2. The derived Doppler widths
and source function are employed to calculate the profiles of the
inner cores of H and K. Extremely good agreement is found between the
calculated and the observed central cores at all five values of . The
variation in the Doppler widths from center to limb is discussed,
and it is concluded that the widening of the profiles to the limb
is caused by an increase in turbulence with height, combined with
anisotropy. The comparison of the Doppler widths derived for Ca ii with
results previously obtained for the X 10830 line of He I supports the
hypothesis that the chromosphere is heterogeneous and is composed of
regions of quite different physical properties.
Title: On the Empirical Determination of Line-Absorption Coefficints.
Authors: Goldberg, Leo
Bibcode: 1958ApJ...127..308G
Altcode:
A method is described for extracting the wave4ength dependence of the
line-absorption coefficient from observed line profiles, similar in
principle to those employed by de Jager and by Athay and Thomas for
the derivation of the Doppler widths of the Balmer lines. The method
requires the accurate observation of the profiles of pairs of lines
of known relative strengths in multiplets but necessitates no prior
knowledge of the atmospheric model. The method is applied to the
determination of the Doppler widths of the X 6238 and X 6248 solar
lines of Fe+ from the recent observations of Suemoto.
Title: The Profile of Hα during the Limb Flare of February 10, 1956.
Authors: Goldberg, Leo; Mohler, Orren C.; Muller, Edith A.
Bibcode: 1958ApJ...127..302G
Altcode:
Profiles of the Ha line in a very bright loop prominence associated
with the great limb flare of February 10, 1956, show pronounced violet
asymmetries. Despite the fact that the centers of different profiles,
made at several points in the line on two different exposures, exhibit
relative Doppler displacements as high as 0.8 A, the shapes of all
the profiles can be accounted for by the superposition on the main Ha
profile of an additional component centered between 1.5 and 2.0 A to
the violet. The possibility is discussed that the asymmetry may have
been caused by the presence of abnormal amounts of deuterium, presumably
generated by nuclear reactions during the flare event. It is concluded
that, although the evidence for deuterium is not conclusive, it would be
extremely important to observe other similar flareassociated prominences
in the future, with modern high-dispersion spectrographs. Observations
should also be made simultaneously on at least one additional line of
an element other than hydrogen, in order to eliminate velocity effects.
Title: The observatories of the University of Michigan.
Authors: Goldberg, L.
Bibcode: 1958AJ.....63..366G
Altcode:
No abstract at ADS
Title: The Photosphere of the Sun
Authors: Pierce, A. K.; Goldberg, L.
Bibcode: 1958HDA....52....1P
Altcode:
No abstract at ADS
Title: Turbulent Velocities Inferred from the H and K Emission Lines
in Stellar Spectra.
Authors: Goldberg, Leo
Bibcode: 1957ApJ...126..318G
Altcode:
IL is shown that the turbulent velocities inferred by Wilson and Bappu
(1957) from the widths of the H and K emission lines in stellar spectra,
on the assumption of origin in an optically thin layer, can probably
be reduced by a factor of 3 or 4 on the not unreasonable hypothesis
that the lines are broadened by the Doppler effect in an optically
thick atmosphere
Title: A Connexion Between the Granulation and the Structure of the
Low Chromosphere
Authors: Goldberg, Leo; Mohler, Orren C.; Brown, Jacqueline D.
Bibcode: 1957Natur.179..369G
Altcode:
PHOTOGRAPHS of the solar spectrum made with the vacuum spectrograph
of the McMath-Hulbert Observatory have revealed a variety of
interesting and complex features in the structures of the Fraunhofer
lines1. The appearance of the hydrogen line cores suggests
an underlying, diffuse component that evidently originates in the
photosphere, upon which are superposed a series of streaks that must
be of chromospheric origin. The weaker metallic lines (of Rowland
intensity less than about 10) also fluctuate in width and intensity
and have a characteristic zig-zag appearance caused by the Doppler
shifts of ascending and descending gas columns which are associated
with the granulation in the photosphere.
Title: The chemical composition of the solar atmosphere.
Authors: Goldberg, Leo; Muller, Edith A.; Aller, Lawrence H.
Bibcode: 1957AJ.....62R..15G
Altcode:
The abundances of some 40 elements relative to hydrogen have been
redetermined in a new investigation of the chemical composition of
the solar atmosphere from the Fraunhofer spectrum. The measi~irements
of equivalent widths by the Utrecht group and by Allen's have been
supplemented by infrared data and by measurements of selected lines on
vacuum spectrograph plates from the McMath-Hulbert Observatory. The
method of analysis is that of weighting functions, as developed by
Minnaert and Claas for weak lines and by Pecker for lines of medium
strength. In this method, the equivalent width of each line is related
to the abundance by an integral over the model atmosphere, in which
the integrand is the product of the number of absorbing atoms, the
weighting function at each point in the atmosphere, and a so-called
saturation function which reduces to unity for weak lines. Special
numerical techniques for the evaluation of these integrals have been
devised by Elste and adapted by him for computation with the Michigan
high-speed computers, MIDAC and the IBM 650. An extensive set of these
integrals has been tabulated by Elste for both weak lines and those of
medium strength covering the wave-length region XX4ooo to 22,000 and
a wide range of excitation potentials. This tabulation has provided
the basis for the present investigation of solar abundances. The
model atmosphere employed was derived by Waddell and Pierce from the
latter's recent observations of solar-limb darkening and spectral-
energy distribution, but with the pressure distribution modified
by Elste in accordance with the work of Weidemann. The results are
generally in good agreement with those of other workers, but there
are notable exceptions, especially for those abundances that depend
on the analysis of lines of medium strength. The reason appears to be
that the shape of the curve of growth in the transition region differs
markedly for lines originating at different depths in the atmosphere. It
is anticipated that the results quoted here can be further improved
when new photoelectric observations of weak lines are secured with
the vacuum spectrograph of the McMath-Hulbert Observatory. However,
for a large number of elements, uncertainties in the f-values present
the major obstacle to definitive abundance determinations. University
of Michigan, Ann Arbor, Mich.
Title: The origin of the double reversal in the Fraunhofer H and
K lines.
Authors: Goldberg, Leo; Muller, Edith A.
Bibcode: 1957AJ.....62R..92G
Altcode:
The discovery by 0. C. Wilson of a correlation between the absolute
magnitudes of the G, K and M stars and the widths of the emission
reversals in their K-line cores emphasizes the importance of
establishing the mechanism both for widening the H and K emission-line
cores in the sun and for producing the central self-reversal. Evidence
is presented that favors Doppler broadening on the one hand and
abundance broadening on the other. It is shown that the apparently
conflicting arguments for the two kinds of broadening can be resolved
if the cores of the H and K lines are formed in an optically-thick
chromosphere in which the excitation temperature decreases with
height. Methods are developed for the derivation of the excitation
temperature and Ca+ density distributions from the observed profiles and
it is shown that the resulting model accounts satisfactorily for the
main features of the observed profiles both at the center of the disk
and at the limb. University of Michigan Observatory, Ann Arbor, Mich.
Title: A connection between the granulation and the structure of
the low chromosphere.
Authors: Goldberg, Leo; Mohler, Orren C.; Brown, Jacqueline D.
Bibcode: 1957AJ.....62Q..92G
Altcode:
Isophotometer tracings of a plate of the Fraunhofer spectrum in the
region of H~ show an interesting connection between the structures of
the H~ line and of the Fei line N4859.747 (Rowland intensity 4). The
Hfl line is resolved into structures as small as 3" or less, and the
detail in the neighboring metallic lines is equally good. Over an
interval of about 6' on the disc, 41 features in the H~ line were
measured for radial velocity with respect to the underlying photo-
spheric component of the line core. Similarly, velocity shifts
were measured in the neighboring Fei line at points in the line
corresponding to the positions of the 41 H~ structures. The results
obtained are as follows: i) There is a remarkable association of the H~
structures with violet shifts in the Fei line. Of the 41 measured H~
structures, 30 are associated with violet shifts in the Fei line,
7 with red shifts, and 4 with zero shifts; 2) The H~ structures are
themselves predominantly shifted to the violet. The statistics show
26 violet shifts, I I red shifts, and 4 zero shifts; 3) The velocity
spread in the Hfl line is about three times as great as that in the
Fei line, the rms values being 0.64 and 0.24 km/sec, respectively. It
is tentatively suggested that the violet- shifted structures observed
in the hydrogen lines represent extensions of the granular columns
into the low chromosphere. The inequality between the negative and
positive shifts in the H~ line may be attributed to the fact that on
the average the ascending columns are at a somewhat higher temperature
than the descending columns. Since a difference of only a few hundred
degrees in temperature causes an enormous difference in the population
of the two-quantum level of hydrogen, the relative absence of structures
with descending velocities could be due to vanishingly small optical
depth in the cooler columns. Further clarification may be expected
from studies now being carried on with lines covering a large range
of optical depth and excitation characteristics, including Ha, the K
line of Ca+, the D lines of sodium, and the Mg b lines. University of
Michigan Observatory, Ann Arbor, Mich.
Title: Reports of observatories
Authors: Goldberg, L.
Bibcode: 1956AJ.....61..330G
Altcode:
No abstract at ADS
Title: Preliminary Results with a Vacuum Solar Spectrograph.
Authors: McMath, Robert R.; Mohler, Orren C.; Pierce, A. Keith;
Goldberg, Leo
Bibcode: 1956ApJ...124....1M
Altcode:
New observations of the solar spectrum with a high-resolution vacuum
spectrograph reveal a wealth of detail in the cores of all Fraunhofer
lines observed both in the normal disk and in areas exhibiting
various kinds of solar activity. The lines show fluctuations in width,
intensity, and position over intervals as small as 2 seconds of arc. A
representative collection of photographs is presented, together
with tentative conclusions derived from inspection and preliminary
measurement. Measurements of Doppler shifts have been carried out in
considerable detail for the two lines Cr X 4626 and Ba+ X 5853. The
random turbulent velocity at the center of the disk is 0 70 km/sec
for the chromium line and O. km/sec for the ionized barium line. For
both lines the random turbulent velocity appears to increase toward
the limb. The velocity shifts observed for the Ha and sodium D lines
are of the same order of magnitude as those of the weaker metallic
lines. The disk observations of the Fraunhofer lines of hydrogen and
ionized calcium seem to he consistent with a qualitative model of the
low chromosphere, consisting of relatively hot clouds of gas and with
cooler regions both above and between the hot regions. Both the K2
emission in ionized calcium and the wide absorption features in Ha
seem to originate in the hot regions; from the appearance of these
line features near the limb it seems that the hot regions contribute
a substantial fraction of the hydrogen and ionized calcium emission
in the very low chromosphere. The profiles of Ha at the extreme limb
and of the K line and other strong metallic lines on the disk favor
the conclusion of Adams and Burwell that central self-reversal is a
general characteristic of most strong chromospheric profiles. The
similarity between the intensity and velocity fluctuations in the
core of the strong magnesium line X 5167 and in those of neighboring
weaker lines implies either a chromospheric origin for the centers of
these weaker lines or the extension of the photospheric granules into
the low chromosphere. The preliminary nature of the foregoing results
is emphasized.
Title: The Width of the Infrared Helium Line in the Solar Spectrum.
Authors: Mohler, Orren C.; Goldberg, Leo
Bibcode: 1956ApJ...124...13M
Altcode:
Measurements of intensity and half-width are reported for the Fraunhofer
line He I 10830 After correction for instrumental broadening and
blending, the width at half4ntensity, averaged over the center of the
disk and the four limbs, is 0.91 A. Within the error of measurement,
the line widths show no center-to4imb variation The line appears
to be broadened entirely by the Doppler effect, with AND = 0.55
A, corresponding to an r.m.s. velocity of about 15 km/sec. If the
broadening is entirely thermal, the kinetic temperature is about 50000
K. Although the line is probably formed in localized hot regions of the
chromosphere, it is not yet clear whether or not the derived velocity
contains a turbulent, as well as a thermal, component.
Title: Solar Physics
Authors: Goldberg, Leo; Menzel, Donald H.
Bibcode: 1956SCoA....1..103G
Altcode:
No abstract at ADS
Title: The abundance of atmospheric carbon dioxide and its isotopes
Authors: Goldberg, Leo
Bibcode: 1956VA......2..855G
Altcode:
No abstract at ADS
Title: Infrared Solar Spectrum
Authors: Goldberg, Leo
Bibcode: 1955AmJPh..23..203G
Altcode:
An account is given of recent results obtained from the study of
the infrared solar spectrum with modern grating spectrometers and
detectors. The discussion is divided into three parts, namely, the
sun's continuous spectrum, the solar absorption-line spectrum, and
the telluric- or terrestrial-line spectrum.
Title: The Abundances of the Elements in the Sun
Authors: Goldberg, Leo; Aller, Lawrence H.; Müller, Edith A.
Bibcode: 1955stat.conf..141G
Altcode: 1954stat.conf..141G
No abstract at ADS
Title: The Temperature of the Low Chromosphere.
Authors: Goldberg, Leo
Bibcode: 1954ApJ...120..185G
Altcode:
No abstract at ADS
Title: The Width of Hα in Solar Flares.
Authors: Goldberg, Leo; Dodson, Helen W.; Müller, Edith A.
Bibcode: 1954ApJ...120...83G
Altcode:
It is shown that the observed large widening, at or near maximum,
of the Ha emission line in certain solar flares can be explained as a
consequence of radiation damping and the high abundance of two- quantum
H atoms in the line of sight. When the effective width `of the Ha line
is calculated according to the theory of self-absorption, the assumption
of radiation damping leads to agreement with the observed lines widths
when the number of two-quantum H atoms lies in the approximate range per
cm2 in the line of sight. If it is assumed that the lateral extension
of a flare is large compared with its thick- ness, the theory predicts
that the effective width of Ha should be proportional to the square
root of sec 0, where 0 is the angular distance from the center of the
solar disk. Study of the Ha line widths of 610 flares reported in the
Quarterly Bulletin of the I.A.U. for the period January, 1949, through
June, 1952, reveals that the average line width increases steadily
with increasing central meridian distance of the flares. Furthermore,
flares with exceptionally wide lines ( 4.0 A) are observed most often
in flares 45 or more from the central meridian. The relation between
effective line width and central intensity found by Ellison is explained
as primarily a consequence of self-absorption. Finally, the existing
observational evidence in favor of the Stark effect as an important
cause of the line broadening is examined and found unconvincing.
Title: The Absorption Spectrum of the Atmosphere
Authors: Goldberg, Leo
Bibcode: 1954eap..book..434G
Altcode:
No abstract at ADS
Title: Discussion of a Possible Cooperative Telescope
Authors: Goldberg, L.; Linnell, A. F.
Bibcode: 1954asph.conf..107G
Altcode:
No abstract at ADS
Title: Carbon Monoxide in the Sun.
Authors: Goldberg, Leo; Müller, Edith A.
Bibcode: 1953ApJ...118..397G
Altcode:
Nearly 300 llnes of carbon monoxide have been identified in the spectrum
of the solar limb between 2.29 and 2.50 . The lines belong to the
overtone bands 24), 31, 42, 33, , and 7-5. Analysis of the solar wave
lengths has led to a new determination of the vibrational and rotational
constants of the CO molecule. The measured absorption coefficients
of Penner and Weber and the theoretical values of Scholz have been
applied to the measured equivalent widths at the center of the disk. The
resulting equivalent abundance of CO is 1.45 X t0' molecules per square
centimeter above the photosphere, and the excitation temperature is
4300 K. It is shown from model-atmosphere calculations that solar Co is
concentrated near the top of the photosphere and hence that the derived
excitation temperature is consistent since it agrees with the boundary
temperature. At present, it is not known whether the dissociation
energy of CO is 9.6 or 11.1 e.v. If the lower value is correct, the
solar-line intensities suggest that the boundary temperature is less
than 4500 K. The exact value of the temperature depends on the choice of
atomic abundances for 0 and C. The low intensities of the fundamental
band lines of CO in the 4.6 region are explained as a consequence of
(1) the high opacity of the solar atmosphere at long wave lengths,
(2) the importance of stimulated emissions in the infrared, and (3)
the small collisional line widths in the sun's outer layers.
Title: Table of Infrared Solar Lines, 1.4-2.5 μ.
Authors: Mohler, Orren C.; Pierce, A. Keith; McMath, Robert R.;
Goldberg, Leo
Bibcode: 1953ApJ...117...41M
Altcode:
Accurate wave lengths and measurements of equivalent width are given
for 888 solar lines in the spectral region 1. 2.5 . The number of
solar lines has been more than doubled, as compared with previous
preliminary studies in this spectral region. The wave lengths of
the solar lines are referred to those of the Fraunhofer lines in the
visible and very near infrared spectrum by the method of overlapping
orders. The root-mean-square errors of the infrared standard wave
lengths, as derived from repeated measurements of individual lines,
are +0.13 A for the l.6 region and +0.17 A for the 2.3 region. The
equivalent widths are preliminary. The estimated errors are between
10 and 100 per cent, depending upon the degree of blending. About 470
infrared solar lines have been tentatively identified with atoms of H,
K, C, At, Na, Si, Mg, Ca, Ni, and Fe and with first overtone lines
of CO. Comparisons between solar wave lengths and those measured in
the laboratory or predicted from term values reveal somewhat closer
agreement, on the average, between the solar and the predicted values
than between the solar and the laboratory values.
Title: Introduction
Authors: Goldberg, Leo
Bibcode: 1953sun..book....1G
Altcode:
No abstract at ADS
Title: The Abundance of CO in the Sun and in the Earth's Atmosphere
Authors: Goldberg, Leo; McMath, Robert R.; Mohler, Orren C.; Pierce,
A. Keith
Bibcode: 1952PhRv...85..481G
Altcode:
No abstract at ADS
Title: Identification of CO in the Solar Atmosphere
Authors: Pierce, A. K.; Goldberg, L.; McMath, R. R.; Mohler, O. C.
Bibcode: 1952PhRv...85..140P
Altcode:
No abstract at ADS
Title: The Abundance of CO in the Sun and in the Earth's Atmosphere
Authors: Pierce, A. K.; Goldberg, L.; McMath, R. R.; Mohler, O. C.
Bibcode: 1952PhRv...85..418P
Altcode:
No abstract at ADS
Title: H-alpha survey.
Authors: Goldberg, L.
Bibcode: 1951AJ.....56..160G
Altcode:
No abstract at ADS
Title: The Abundance and Vertical Distribution of Methane in the
Earth's Atmosphere.
Authors: Goldberg, Leo
Bibcode: 1951ApJ...113..567G
Altcode:
Theoretical expressions are derived for the equivalent widths of
CY4 lines formed in the earth's atmosphere which take into account
the variation of pressure and temperature with altitude in the
atmosphere. When allowance is made for the curvature of the earth;
information on the vertical distribution of CII 4 can be obtained from
low-sun observations. The theoretical formulae have been employed for
the analysis of observations of the t, 5 , and to-it lines in the 2 P3
band of CH4 at 1.666 in the solar spectrum. From observations made at
Lake Angelus, Michigan, and Mount Wilson, California, the total numbers
of CH4 molecules per square centimeter through the zenith are found to
be 3.2 X t0 and 2.6 X 1019, respectively. The ratio of abundances is
very nearly that which would be expected if the distribution of CH4 is
world-wide and falls off exponentially with height at the same rate as
the main body of the atmosphere. The observations are well represented
by theoretical curves of growth for pure damping, with /4ir = 1.2 X
t0 for Lake Angelus and /4ir = 1.0 X t0 for Mount Wilson. Within the
experimental error the ratio of damping constants is equal to the ratio
of ground-level pressures at the two stations, in agreement with theory.
Title: Reports: Lamont-Hussey Observatory, Bloemfontein, South Africa
Authors: Goldberg, Leo
Bibcode: 1950AJ.....55..194G
Altcode:
No abstract at ADS
Title: Stellar and nebular spectroscopy. Atmospheres of B-type
stars. Studies of A-type stars.
Authors: Goldberg, L.
Bibcode: 1950AJ.....55..192G
Altcode:
No abstract at ADS
Title: Observations of Solar Limb Darkening Between 0.5 and
10.2&mu
Authors: Pierce, A. K.; McMath, R. R.; Goldberg, Leo; Mohler, O. C.
Bibcode: 1950ApJ...112..289P
Altcode:
Measurements of solar limb darkening are tabulated for thirteen
wave lengths between 0.5 and 10.2 . Observations in the wave-length
region 0.5-2.2 were carried out with the McGregor Tower telescope and
spectrometer for the interval cos 0 = 1.0 to cos 0 = 0.16. Measurements
at three longer wave lengths were made with a Perkin-Elmer spectrometer
attached to the 24inch reflector and covered the interval cos 0 = 1.0
to cos 0 = 0.2. At certain wave lengths the near infrared measurements
agree with those of Abbot's to within 0.1 per cent; at other wave
lengths the systematic differences are as large as 1 per cent. It is
found that the degree of limb darkening decreases in the infrared
from 3.5 to 10.2 . This result is qualitatively consistent with a
systematic increase of the solar continuous opacity toward longer wave
lengths in the infrared, as predicted by theoretical calculations of
the absorption coefficient of the negative hydrogen ion.
Title: Position of the Portage Lake Observatory
Authors: Goldberg, Leo
Bibcode: 1950AJ.....55..160G
Altcode:
No abstract at ADS
Title: New Solar Lines in the Spectral Region 1.97-2.49 μ.
Authors: Goldberg, Leo; Mohler, Orren C.; Pierce, A. Keith; McMath,
Robert R.
Bibcode: 1950ApJ...111..565G
Altcode:
Measurements of wave length and of percentage central absorption are
given for 109 solar lines in the region 1.97-2.49 of the infrared
solar spectrum. The lines were found on tracings obtained with
the high-dispersion spectrometers and Cashman PbS cells of the
McMath-Hulbert Observatory at Lake Angelus and at the Mount Wilson
Observatory. Forty-seven lines have been identified as arising from
neutral atoms of H, Na, Si, Mg, Al, Ca, and Fe. The relative scarcity
of solar lines in the 2.2 IL region is discussed, and a qualitative
explanation is given in terms of the variation with wave length of
the continuous absorption coefficient of H- combined with the solar
temperature gradient.
Title: Recent advances in infra-red solar spectroscopy
Authors: Goldberg, L.
Bibcode: 1950RPPh...13...24G
Altcode:
No abstract at ADS
Title: The 3n3 Band of Telluric CO2 in the Solar Spectrum
Authors: Pierce, A. K.; Goldberg, L.; Mohler, O. C.; McMath, R. R.
Bibcode: 1950PhRv...78...74P
Altcode:
No abstract at ADS
Title: N2O Bands in the Solar Spectrum
Authors: Pierce, A. K.; McMath, R. R.; Mohler, O. C.; Goldberg, L.;
Donovan, R. A.
Bibcode: 1950PhRv...78...65P
Altcode:
No abstract at ADS
Title: Telluric Bands of CH_{4} in the Solar Spectrum.
Authors: McMath, Robert R.; Mohler, Orren C.; Goldberg, Leo
Bibcode: 1949ApJ...109...17M
Altcode:
An all-reflecting telescope and spectrometer have been employed in
conjunction with a Cashman PbS cell to secure a direct-intensity map
of the solar spectrum in the region of 0.8-2.5 ~i with a resolution
of about 50,000. Four molecular-band systems at 1.66, 2.20, 2.32,
and 2.37 ~ have been identified as the P1 + V4~ V3 + P4 and ~2 + P3
transitions of CH4 in the earth's atmosphere. A preliminary analysis
of the wave numbers of the 2P3 rotational components indicates
second-order deviations from theory. The average half-spacing B0 is
found to be 5.163, as compared with the value B0 = 5.252 obtained by
Childs. A comparison of the 2P3 telluric line intensities with those
produced by a measured quantity of methane at room temperature leads
to a calculated methane abundance in the earth's atmosphere of 1.2
parts in a million by mass, and a temperature of -37° C
Title: New Solar Lines in the Spectral Region 1.52-1.75 μ.
Authors: Goldberg, Leo; Mohler, Orren C.; McMath, Robert R.
Bibcode: 1949ApJ...109...28G
Altcode:
Accurate wave lengths and measurements of percentage central absorption
are given for nearly three hundred new solar lines discovered in the
region 1.52-1.75 ~ of the infrared solar spectrum. The lines were found
on high-resolution, direct-intensity tracings of the spectrum obtained
at the McMath- Hulbert Observatory with the McGregor spectrometer
and a Cashman cell. Ninety-three of the lines have been identified as
belonging to neutral atoms of C, Mg, Al, Si, Fe, Mn, and Ni, mainly
on the basis of wave lengths computed from term values. In addition,
the third, seventh, and eighth members of the Brackett series of
hydrogen have been identified, together with the Na I 4s-4p doublet
at XX 22,054 and 22,081. INTRODUCTIO
Title: Note on Methane in the Infra-Red Solar Spectrum
Authors: Pierce, A. K.; McMath, R. R.; Mohler, O. C.; Goldberg, L.
Bibcode: 1949PhRv...76.1533P
Altcode:
No abstract at ADS
Title: Carbon Dioxide in the Infra-Red Solar Spectrum
Authors: Pierce, A. K.; Goldberg, L.; Mohler, O. C.; McMath, R. R.
Bibcode: 1949PhRv...76.1848P
Altcode:
No abstract at ADS
Title: The solar curve of growth and the kinetic temperature of the
solar reversing layer.
Authors: Pierce, A. Keith; Goldberg, Leo
Bibcode: 1948AJ.....53..202P
Altcode:
An observational solar curve of growth for iron, titanium, and
vanadium was constructed from the gf values of the Kings and the
equivalent widths of Allen. Corrections for the variable continuous
opacity and limb darkening coefficient were applied to each line
before grouping according to excitation potential. For iron and
titanium the displacement of the groups gave a temperature of 46800
K, while for vanadium no proper temperature could be found because
of the non-linear relation between excitation potential and the
displacements. The observed curve of growth was fitted to a theoretical
curve based on the Milne-Eddington model. The "best" fit corresponds to
a most probable Doppler velocity of 2.5 km/sec and values AND/AXN = a
(as defined by Mitchell and Zemansky, Resonance Radiation and Excited
Atoms, Cambridge, 1934) equalling 0.01 for the weaker iron lines
and 0.05 for the stronger. The velocity parameter may be interpreted
in terms of either a kinetic temperature of 57000 plus a turbulent
velocity of 2.0 km/sec or a straight kinetic temperature of 19,5000
K. In an attempt to distinguish between the alternatives of thermal
or turbulent broadening, the half-widths of faint lines of several
elements of different atomic weight, ranging from carbon to nickel,
were determined from the Utrecht Atlas. The widths of these lines,
after correction for instrumental broadening, show a dependence on
atomic weight that accords well with the assumption of thermal widening
at a temperature of 16,0000 K. Observatory, University of Michigan,
Ann Arbor, Mich.
Title: Recent developments in infra-red solar spectroscopy.
Authors: McMath, R. R.; Mohler, O. C.; Goldberg, L.
Bibcode: 1948AJ.....54Q..44M
Altcode:
Since the late fall of 1947, the ~cGregor tower of the McMath-Hulbert
Observatory has been used for study of the infra-red solar spectrum
beyond the photographic limit. A specially designed, all-mirror optical
system and Pfund-type grating spectrometer, with monochromator,
have been used in conjunction with a Cashman leadsulphide cell to
obtain direct-intensity tracings of the solar spectrum over the
entire region between 8ooo and 25000 A. The spectrum is re corded on
a scale of about five millimeters per angstrom. In the 15000 X region,
lines with separation of 0.3 angstroms are just resolved. Water vapor
absorption almost completely obliterates the spectrum in the regions I
.3-1.5 microns and 1.75-1.95 microns. The intervening portions of the
spectrum, however, are relatively clear and contain a wealth of solar
atomic lines, as well as telluric molecular lines and bands. Progress in
identification has been slow, largely because of the complete absence
of high-resolution laboratory studies in this region of the infra-red
spectrum. Approximately 200 solar atomic lines have been identified
in the infra-red spectrum on the basis of wave lengths computed from
known atomic energy levels. The elements for which lines have been
found include Fe, Si, Na, AIg, Al, C, Ca, as well as the third and
seventh members of the Brackett series of hydrogen. The vast majority
of these lines have excitation potentials higher than five volts. Band
systems of molecules originating in the earth's atmosphere constitute
some of the most interesting features of the infra-red spectrum. Among
these are four CO1 bands in the 1.6 micron region, which have been
resolved for the first time, and three strong bands of CO1 at 2.1
microns. Among the identified molecular bands, those of ammonia and
methane are particularly noteworthy. The evidence for ammonia as
a constituent of the earth's atmosphere is very strong, while the
evidence for methane is conclusive. Mc Math- Hulbert Observatory,
Pontiac, Mich. and University of Michigan Observatory, Ann Arbor, Mich.
Title: The Solar Corona and Ultraviolet Radiation
Authors: Goldberg, Leo; Menzel, Donald H.
Bibcode: 1948HarMo...7..279G
Altcode: 1948cent.symp..279G
No abstract at ADS
Title: Evidence for coronal absorption on the solar disk.
Authors: McMath, Robert R.; Goldberg, Leo; Mohler, Orren C.
Bibcode: 1947AJ.....52R.156M
Altcode:
A broad, diffuse absorption line at 637A.45 I.A. + 0.01 has been found
in the spectrum of the solar disk on plates obtained with the McGregor
sbectrograph and the 70-ft. tower telescope of the McMath-Hulbert
Observatory. Its width has been estimated at 0.3 to 0.4 A. The line
is seen very faintly at the center of the disk, becoming strongly
accentuated at the limb. It appears equally intense all around the
limb and no significant variations in intensity or in wave length
have been found. The appearance of the line and the closeness of its
position to that of the red coronal line (given by Lyot as X6374.5I +
0.03) suggest the possibility that the absorption line arises from
atoms of Fe x. The evidence for or against the identification as Fe
x is discussed, the results at present being inconclusive. If the
line is due to Fe x, its intensity and distribution around the limb
are such that a considerable abundance of Fe x must be present in the
chromosphere. In this connection attention is called to the observation
by H. D. and H. W. Babcock' of a similar diffuse absorption line
at X6374.40 in the flash spectrum outside of eclipse. The Babcocks
reported that the line was flanked by emission components on either
side. A predicted line of Fe I (ziC2o - e702) occurs at X6374.43. No
other members of this multiplet have been observed with certainty in
the solar spectrum, however, and the width of the observed absorption
line makes its identification as predicted Fe I unlikely, unless it
is closely blended with another faint line. A search has been made
for a similar absorption line at the position of the green coronal
line 5302.86, identified by Edlen as arising from Fe xiv. No such
absorption line has been found. It is pointed out that excitation
conditions in the chromosphere favorable for the presence of Fe
x would not necessarily produce Fe xiv. I.Pub. A. S. P. 46, 132,
1934. McMath-Hulbert Observatory, Lake Angelus, Pontiac, Mich.
Title: Statistical equilibrium of helium atoms in gaseous nebulae
Authors: Goldberg, Leo
Bibcode: 1946PAAS...10R..13G
Altcode:
No abstract at ADS
Title: Continuous absorption coefficients for complex atoms
Authors: Goldberg, Leo; Aller, L. H.
Bibcode: 1946PAAS...10R.162G
Altcode:
No abstract at ADS
Title: Atomos, estrellas Y nebulosas
Authors: Goldberg, Leo; Aller, Lawrence Hugh
Bibcode: 1944aeyn.book.....G
Altcode: 1944QB461.G617.....
No abstract at ADS
Title: Book reviews: Atoms, Stars, and Nebulae
Authors: Goldberg, Leo; Aller, Lawrence H.
Bibcode: 1943PA.....51..289G
Altcode:
No abstract at ADS
Title: Atoms, stars and nebulae
Authors: Goldberg, Leo; Aller, Lawrence Hugh
Bibcode: 1943asn..book.....G
Altcode: 1943QB461.G6.......
No abstract at ADS
Title: Physical Processes in Gaseous Nebulae. XV.
Authors: Goldberg, Leo
Bibcode: 1941ApJ....93..244G
Altcode:
The statistical equilibrium of an assembly of neutral helium atoms
has been investigated with refer- ence to the problem of gaseous
nebulae. The helium atom was assumed to contain an infinite number of
energy levels, but a single equation of equilibrium was written down
for all triplet levels above 2 3po and, similarly, for all singlets
above 2 ipo Mean values are thus obtained for the popiilations of the
high singlets and the high triplets. The population is given in terms
of a quantity b~, the ratio between the true population and the value
for thermodynamic equilibrium at a temperature T~. The temperature T~
refers to an assumed Maxweffian distribution of the free electrons. The
nebular atoms are assumed to be opaque to the stellar radiation field
oniy in the frequencies cor- responding to absorptions from levels i
IS, 2 Is, and 2 ~S. Numerical solutions of the equations are tabu-
lated for stellar temperatures, T1, of 50,000° and 100,000° and
electron temperatures of 5000° 10,000°, 20,0000, 40,000°, and
80,0000, and also for the special case T1 = T6 = 20,0000
Title: An Investigation of the Rowland Intensity Scale.
Authors: Menzel, Donald H.; Goldberg, Leo; Cook, Edward M.
Bibcode: 1940ApJ....91..320M
Altcode: 1940HarRe.195....1M
A new calibration of Rowland's scale of solar intensities has been
derived with the aid of the theoretical strengths of multiplets in
transition arrays. The calibration takes the form of a double-entry
table giving average values of log X0, where X0 is the optical depth at
the center of an absorption line, for each Rowland intensity from -3 to
+8 at intervals of 400 A from X 2800 to X 68oo. A total of 37 transition
arrays, representing 13 metaffic elements and 1119 lines in all, was
employed in the analysis. The present calibration is considerably less
steep than the earlier one of Russell, Adams, and Moore
Title: Transition Probabilities for he I.
Authors: Goldberg, Leo
Bibcode: 1939ApJ....90..414G
Altcode: 1939HarRe.182....1G
Simple, screening-type wave functions have been utilized to derive
general expres- sions for the line strengths in the 2s-np and
2p-nd series of He i. The resulting strengths calculated for these
series compare favorably with those computed by 11yi- leraas for the
transitions up to n = 6. A computation of the radiational damping con-
stants shows that the He I triplet damping factors are of the order
of one hundred times smaller than the singlet values, a result that
arises from the metastability of the lowest triplet level and from
the short wave length of the fundamental singlet line. The expressions
for the discrete f-values have been extended to the continuum by the
device of letting n -~ ~K, where K is a continuous quantum number,
according to the method outlined by Menzel and Pekeris. The resulting
expressions provide for the determination of the absorption coefficients
for bound-free transitions from the 2S and 2~ levels. Thef-sum rule
of Kuhn and Thomas-Reiche predicts that the sum of thef-values of all
transitions from a singly excited level of He I should equal unity. The
rule appears to be satisfactorily obeyed for all but the 2 ~S level,
for which the sum is 0.849
Title: Scientific Books: The Distribution of the Stars in Space
Authors: Goldberg, Leo
Bibcode: 1939Sci....90..110G
Altcode: 1939Sci....90..110B
No abstract at ADS
Title: A Study of the Equivalent Width of Helium Lines in Early-Type
Stars.
Authors: Goldberg, Leo
Bibcode: 1939ApJ....89..623G
Altcode: 1939HarRe.167....1G
The theoretical strengths of the He i lines in the diffuse 2p-nd
series have been employed, together with E. G. Wiffiams' measures of
equivalent widths, to construct curves of growth for the helium lines
in fifty-seven 0- and B-type stars. Comparisons of these curves with a
theoretical curve for helium atoms at a temperature of 20,0000 per- mits
a determination of the quantifies V and ~. V is defined by the relatio
Title: The Temperature of the Solar Chromosphere.
Authors: Goldberg, Leo
Bibcode: 1939ApJ....89..673G
Altcode:
The theoretical strengths of the diffuse triplet lines of He r have
been employed in connection with Menzel and Cillié's measures of
1932 chromospheric lines in an attempt to determine the excitation
temperature of the solar chromosphere. The temperature appears to
increase with the height, ranging from 4300° for the chromospheric
slab 670 km above the solar limb to 6700° for a height of 2330 km. The
diffuse singlet lines of He i appear to be anomalously faint relative
to the dif- fuse triplets. The suggestion is made that, in a rarefied
chromosphere, the combination of the metastabffity of the 2~S level
and a possible excess of ultraviolet radiation in the region at 500
A may account for the relative faintness of the singlets
Title: Equivalent widths and the reversing-layer temperature
Authors: Menzel, Donald H.; Goldberg, Leo; Baker, James G.
Bibcode: 1939PAAS....9R..51M
Altcode:
No abstract at ADS
Title: A study of the equivalent widths of helium lines in early-type
stars
Authors: Goldberg, Leo
Bibcode: 1939PAAS....9S.220G
Altcode:
No abstract at ADS
Title: Temperature of the solar chromosphere
Authors: Goldberg, Leo
Bibcode: 1939PAAS....9R.220G
Altcode:
No abstract at ADS
Title: Equivalent Widths and the Temperature of the Solar Reversing
Layer
Authors: Menzel, Donald H.; Baker, James G.; Goldberg, Leo
Bibcode: 1938ApJ....87...81M
Altcode: 1938HarRe.145....1M
Allen's extensive determinations of equivalent widths of Fraunhofer
lines provide important observational material for an analysis of the
physical state of the solar atmos- phere. A comparison of the observed
intensities of absorption lines, as read from an em- pirical curve of
growth, with the theoretical strengths of lines in a transition array
makes it possible to calculate the effective excitation temperature of
the reversing layer. Tem- peratures of 4350° ± 200° and 41500 ±
50° are computed from the lines of Ti i and Fe I, respectively. A
qualitative discussion of the errors inherent in the theoretical
calculation of mul- tiplet strengths is given, and a method for
calculating the reversing-layer temperature by means of the f-file sum
rule is described. The application of this method to the lines of Ti i
yields a temperature of 4400° ± ba0. Since the sum rule is independent
of the coupling in an atom, and is therefore free of the assumptions
involved in the calculation of multiplet strengths, the value 4400° is
adopted, for purposes of discussion, as the mean excitation temperature
of the solar reversing layer. If the opacity of the solar atmosphere
varies with wave length, we should expect to find the numbers of atoms,
as derived from equivalent widths, depending upon wave length as well
as upon the temperature and excitation potential. The data for Fe in-
dicate an opacity law almost independent of wave length. These results,
however, are not definitive. Since the mean lower excitation potentials
increase systematically with wave length, opacity and temperature
effects are correlated. The data for Ti, where no systematic correlation
exists, are not inconsistent with an opacity varying as X~, whereas
theory predicts a law varying approximately as X3e-hc/XkT. An attempt
is made to rec- oncile the observations and the theoretical values
Title: The Intensities of Helium Lines.
Authors: Goldberg, Leo
Bibcode: 1938PhDT.........1G
Altcode:
No abstract at ADS
Title: Note on Relative ƒ-VALUES for Lines of fe I
Authors: Menzel, Donald H.; Goldberg, Leo
Bibcode: 1937ApJ....85...40M
Altcode: 1937HarRe.131....1M
In connection with R. B. and A. S. King's recent intensity measurements
of Fe i absorption lines in furnace spectra, the omission of a weight
factor in reducing equiva- lent widths to relative f-values is noted. In
order to yield true f-values, the values as published must be divided
by the statistical weight of the lower level
Title: Multiplet Strengths for Transitions Involving Equivalent
Electrons
Authors: Menzel, Donald H.; Goldberg, Leo
Bibcode: 1936ApJ....84....1M
Altcode: 1936HarRe.126....1M
Bacher and Goudsmit have shown that the parentage of a term arising from
a shell of equivalent electrons is expressible as a linear combination
of all the terms of the ion. When two or more terms of a kind occur in
the same configuration, however, the method gives only the sum of the
parentages of the terms involved. The resulting parentages may be used
with the well-known Kronig formulae to calculate multiplet strengths
in transition arrays where the jumping electron is equivalent to others
in oniy one of the two configurations. At the present time, the method
is applicable to all arrays involving equivalent s- and p-electrons,
and to arrays involving not more than three equivalent d-electrons. For
convenience of calculation a table containing the parentages of terms
arising from equivalent electron shells is given. The table also
lists the configurations of astro- physical interest to which these
parentages may be applied in the calculation of multi- plet strengths
Title: Note on Absolute Multiplet Strengths
Authors: Goldberg, Leo
Bibcode: 1936ApJ....84...11G
Altcode:
A table of factors is given by means of which the relative multiplet
strengths tabu- lated by the writer in an earlier paper may be converted
to absolute strengths in terms of c2, the square of the one-electron
matrix component. ~ is a constant for any given tran- sition array
Title: Relative Multiplet Strengths in LS Coupling
Authors: Goldberg, Leo
Bibcode: 1935ApJ....82....1G
Altcode: 1935HarRe.112....1G
The relative strengths of different multiplets in LS coupling have
been calculated and tabulated for sixty-five transition arrays of
astrophysical interest. In arrays where the jumping electron belongs to
a shell of three or more equivalent electrons, the method of Condon and
IJiford was employed; all other cases were dealt with by the extension
of Kronig's formulae to relative multiplet strengths, according to
the methods outlined by Shortley. A description of the Condon-TJfford
method is given, together with an illus- tration of its application
to the transition array p3 -p2s. It is shown, also, that in apply-
ing this method, it is necessary to write down the zero-order states
of only one configura- tion, that involving the smallest number of terms