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ADS astronomy entries on 2022-09-14
=author:"Heasley, James N." OR =author:"Heasley, J.N."
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Title: The Pan-STARRS1 Database and Data Products
Authors: Flewelling, H. A.; Magnier, E. A.; Chambers, K. C.; Heasley,
J. N.; Holmberg, C.; Huber, M. E.; Sweeney, W.; Waters, C. Z.;
Calamida, A.; Casertano, S.; Chen, X.; Farrow, D.; Hasinger,
G.; Henderson, R.; Long, K. S.; Metcalfe, N.; Narayan, G.;
Nieto-Santisteban, M. A.; Norberg, P.; Rest, A.; Saglia, R. P.;
Szalay, A.; Thakar, A. R.; Tonry, J. L.; Valenti, J.; Werner, S.;
White, R.; Denneau, L.; Draper, P. W.; Hodapp, K. W.; Jedicke, R.;
Kaiser, N.; Kudritzki, R. P.; Price, P. A.; Wainscoat, R. J.; Chastel,
S.; McLean, B.; Postman, M.; Shiao, B.
2020ApJS..251....7F Altcode: 2016arXiv161205243F
This paper describes the organization of the database and the catalog
data products from the Pan-STARRS1 3π Steradian Survey. The catalog
data products are available in the form of an SQL-based relational
database from MAST, the Mikulski Archive for Space Telescopes at
STScI. The database is described in detail, including the construction
of the database, the provenance of the data, the schema, and how the
database tables are related. Examples of queries for a range of science
goals are included.
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Title: The Pan-STARRS1 Surveys
Authors: Chambers, K. C.; Magnier, E. A.; Metcalfe, N.; Flewelling,
H. A.; Huber, M. E.; Waters, C. Z.; Denneau, L.; Draper, P. W.; Farrow,
D.; Finkbeiner, D. P.; Holmberg, C.; Koppenhoefer, J.; Price, P. A.;
Rest, A.; Saglia, R. P.; Schlafly, E. F.; Smartt, S. J.; Sweeney, W.;
Wainscoat, R. J.; Burgett, W. S.; Chastel, S.; Grav, T.; Heasley,
J. N.; Hodapp, K. W.; Jedicke, R.; Kaiser, N.; Kudritzki, R. -P.;
Luppino, G. A.; Lupton, R. H.; Monet, D. G.; Morgan, J. S.; Onaka,
P. M.; Shiao, B.; Stubbs, C. W.; Tonry, J. L.; White, R.; Bañados,
E.; Bell, E. F.; Bender, R.; Bernard, E. J.; Boegner, M.; Boffi, F.;
Botticella, M. T.; Calamida, A.; Casertano, S.; Chen, W. -P.; Chen,
X.; Cole, S.; Deacon, N.; Frenk, C.; Fitzsimmons, A.; Gezari, S.;
Gibbs, V.; Goessl, C.; Goggia, T.; Gourgue, R.; Goldman, B.; Grant, P.;
Grebel, E. K.; Hambly, N. C.; Hasinger, G.; Heavens, A. F.; Heckman,
T. M.; Henderson, R.; Henning, T.; Holman, M.; Hopp, U.; Ip, W. -H.;
Isani, S.; Jackson, M.; Keyes, C. D.; Koekemoer, A. M.; Kotak, R.;
Le, D.; Liska, D.; Long, K. S.; Lucey, J. R.; Liu, M.; Martin, N. F.;
Masci, G.; McLean, B.; Mindel, E.; Misra, P.; Morganson, E.; Murphy,
D. N. A.; Obaika, A.; Narayan, G.; Nieto-Santisteban, M. A.; Norberg,
P.; Peacock, J. A.; Pier, E. A.; Postman, M.; Primak, N.; Rae, C.;
Rai, A.; Riess, A.; Riffeser, A.; Rix, H. W.; Röser, S.; Russel, R.;
Rutz, L.; Schilbach, E.; Schultz, A. S. B.; Scolnic, D.; Strolger,
L.; Szalay, A.; Seitz, S.; Small, E.; Smith, K. W.; Soderblom, D. R.;
Taylor, P.; Thomson, R.; Taylor, A. N.; Thakar, A. R.; Thiel, J.;
Thilker, D.; Unger, D.; Urata, Y.; Valenti, J.; Wagner, J.; Walder,
T.; Walter, F.; Watters, S. P.; Werner, S.; Wood-Vasey, W. M.; Wyse, R.
2016arXiv161205560C Altcode:
Pan-STARRS1 has carried out a set of distinct synoptic imaging sky
surveys including the $3\pi$ Steradian Survey and the Medium Deep Survey
in 5 bands ($grizy_{P1}$). The mean 5$\sigma$ point source limiting
sensitivities in the stacked 3$\pi$ Steradian Survey in $grizy_{P1}$
are (23.3, 23.2, 23.1, 22.3, 21.4) respectively. The upper bound
on the systematic uncertainty in the photometric calibration across
the sky is 7-12 millimag depending on the bandpass. The systematic
uncertainty of the astrometric calibration using the Gaia frame comes
from a comparison of the results with Gaia: the standard deviation
of the mean and median residuals ($ \Delta ra, \Delta dec $) are
(2.3, 1.7) milliarcsec, and (3.1, 4.8) milliarcsec respectively. The
Pan-STARRS system and the design of the PS1 surveys are described
and an overview of the resulting image and catalog data products and
their basic characteristics are described together with a summary of
important results. The images, reduced data products, and derived data
products from the Pan-STARRS1 surveys are available to the community
from the Mikulski Archive for Space Telescopes (MAST) at STScI.
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Title: VizieR Online Data Catalog: Photometry and proper motions in
Praesepe (Wang+, 2014)
Authors: Wang, P. F.; Chen, W. P.; Lin, C. C.; Pandey, A. K.; Huang,
C. K.; Panwar, N.; Lee, C. H.; Tsai, M. F.; Tang, C. -H.; Goldman, B.;
Burgett, W. S.; Chambers, K. C.; Draper, P. W.; Flewelling, H.; Grav,
T.; Heasley, J. N.; Hodapp, K. W.; Huber, M. E.; Jedicke, R.; Kaiser,
N.; Kudritzki, R. -P.; Luppino, G. A.; Lupton, R. H.; Magnier, E. A.;
Metcalfe, N.; Monet, D. G.; Morgan, J. S.; Onaka, P. M.; Price, P. A.;
Stubbs, C. W.; Sweeney, W.; Tonry, J. L.; Wainscoat, R. J.; Waters, C.
2016yCat..17840057W Altcode:
Data used in this study include photometry and proper motion
measurements within a 5° radius around the Praesepe center
(R.A.=08<SUP>h</SUP>40<SUP>m</SUP>, decl.=+19°42', J2000). Archival
data were taken from the 2MASS Point Sources Catalog (2MASS;
cat. II/246), PPMXL (Roeser et al. 2010, cat. I/317), and Panoramic
Survey Telescope And Rapid Response (Pan-STARRS). <P />Pan-STARRS is
a wide-field (7deg<SUP>2</SUP>) imaging system, with a 1.8m, f/4.4
telescope, equipped with a 1.4 giga-pixel camera. The prototype (PS1),
located atop Haleakala, Maui, USA, has been patrolling the entire
sky north of -30° declination since mid-2010 with a combination of
g<SUB>P1</SUB>, r<SUB>P1</SUB>, i<SUB>P1</SUB>, z<SUB>P1</SUB>, and
y<SUB>P1</SUB> bands. The PS1 filters differ slightly from those of the
SDSS. The g<SUB>P1</SUB> filter extends 20nm redward of g<SUB>SDSS</SUB>
for greater sensitivity and lower systematics for photometric redshift
estimates. SDSS has no corresponding y filter (Tonry et al. 2012,
cat. J/ApJ/750/99). Upon the completion of its 3.5yr mission by early
2014, PS1 will provide reliable photometry and astrometry. <P />Table1
lists the properties of the 1040 candidates. <P />(1 data file).
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Title: Characterization of the Praesepe Star Cluster by Photometry
and Proper Motions with 2MASS, PPMXL, and Pan-STARRS
Authors: Wang, P. F.; Chen, W. P.; Lin, C. C.; Pandey, A. K.; Huang,
C. K.; Panwar, N.; Lee, C. H.; Tsai, M. F.; Tang, C. -H.; Goldman, B.;
Burgett, W. S.; Chambers, K. C.; Draper, P. W.; Flewelling, H.; Grav,
T.; Heasley, J. N.; Hodapp, K. W.; Huber, M. E.; Jedicke, R.; Kaiser,
N.; Kudritzki, R. -P.; Luppino, G. A.; Lupton, R. H.; Magnier, E. A.;
Metcalfe, N.; Monet, D. G.; Morgan, J. S.; Onaka, P. M.; Price, P. A.;
Stubbs, C. W.; Sweeney, W.; Tonry, J. L.; Wainscoat, R. J.; Waters, C.
2014ApJ...784...57W Altcode: 2014arXiv1401.7424W
Membership identification is the first step in determining the
properties of a star cluster. Low-mass members in particular could be
used to trace the dynamical history, such as mass segregation, stellar
evaporation, or tidal stripping, of a star cluster in its Galactic
environment. We identified member candidates of the intermediate-age
Praesepe cluster (M44) with stellar masses ~0.11-2.4 M <SUB>⊙</SUB>,
using Panoramic Survey Telescope And Rapid Response System and Two
Micron All Sky Survey photometry, and PPMXL proper motions. Within
a sky area of 3° radius, 1040 candidates are identified, of which
96 are new inclusions. Using the same set of selection criteria on
field stars, an estimated false positive rate of 16% was determined,
suggesting that 872 of the candidates are true members. This most
complete and reliable membership list allows us to favor the BT-Settl
model over other stellar models. The cluster shows a distinct binary
track above the main sequence, with a binary frequency of 20%-40%,
and a high occurrence rate of similar mass pairs. The mass function
is consistent with that of the disk population but shows a deficit of
members below 0.3 solar masses. A clear mass segregation is evidenced,
with the lowest-mass members in our sample being evaporated from this
disintegrating cluster.
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Title: The Pan-STARRS Moving Object Processing System
Authors: Denneau, Larry; Jedicke, Robert; Grav, Tommy; Granvik,
Mikael; Kubica, Jeremy; Milani, Andrea; Vereš, Peter; Wainscoat,
Richard; Chang, Daniel; Pierfederici, Francesco; Kaiser, N.; Chambers,
K. C.; Heasley, J. N.; Magnier, Eugene A.; Price, P. A.; Myers,
Jonathan; Kleyna, Jan; Hsieh, Henry; Farnocchia, Davide; Waters,
Chris; Sweeney, W. H.; Green, Denver; Bolin, Bryce; Burgett, W. S.;
Morgan, J. S.; Tonry, John L.; Hodapp, K. W.; Chastel, Serge; Chesley,
Steve; Fitzsimmons, Alan; Holman, Matthew; Spahr, Tim; Tholen, David;
Williams, Gareth V.; Abe, Shinsuke; Armstrong, J. D.; Bressi, Terry
H.; Holmes, Robert; Lister, Tim; McMillan, Robert S.; Micheli, Marco;
Ryan, Eileen V.; Ryan, William H.; Scotti, James V.
2013PASP..125..357D Altcode: 2013arXiv1302.7281D
We describe the Pan-STARRS Moving Object Processing System (MOPS), a
modern software package that produces automatic asteroid discoveries
and identifications from catalogs of transient detections from
next-generation astronomical survey telescopes. MOPS achieves
>99.5% efficiency in producing orbits from a synthetic but
realistic population of asteroids whose measurements were simulated
for a Pan-STARRS4-class telescope. Additionally, using a nonphysical
grid population, we demonstrate that MOPS can detect populations of
currently unknown objects such as interstellar asteroids. MOPS has been
adapted successfully to the prototype Pan-STARRS1 telescope despite
differences in expected false detection rates, fill-factor loss,
and relatively sparse observing cadence compared to a hypothetical
Pan-STARRS4 telescope and survey. MOPS remains highly efficient at
detecting objects but drops to 80% efficiency at producing orbits. This
loss is primarily due to configurable MOPS processing limits that are
not yet tuned for the Pan-STARRS1 mission. The core MOPS software
package is the product of more than 15 person-years of software
development and incorporates countless additional years of effort in
third-party software to perform lower-level functions such as spatial
searching or orbit determination. We describe the high-level design
of MOPS and essential subcomponents, the suitability of MOPS for other
survey programs, and suggest a road map for future MOPS development.
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Title: Discovery of the Ultraluminous Type IIn Supernova PS1-11vo
Authors: McKinnon, Ryan; Soderberg, A. M.; Berger, E.; Chornock, R.;
Czekala, I.; Milisavljevic, D.; Margutti, R.; Drout, M.; Challis,
P.; Gezari, S.; Huber, M.; Burgett, W. S.; Chambers, K. C.; Grav, T.;
Heasley, J. N.; Hodapp, K. W.; Jedicke, R.; Kaiser, N.; Kudritzki, R.;
Luppino, G.; Lupton, R.; Magnier, E. A.; Monet, D. G.; Morgan, J. S.;
Onaka, P.; Price, P. A.; Stubbs, C.; Tonry, J. L.; Wainscoat, R. J.
2013AAS...22125304M Altcode:
We report the discovery by the Panoramic Survey Telescope and Rapid
Response System 1 (Pan-STARRS1 or PS1) of PS1-11vo, a Type IIn
supernova (SN) at z = 0.116 with a peak r-band absolute magnitude
of M = -20.4. We also present optical spectroscopic observations
from the Apache Point Observatory Echelle Spectrograph, the Gemini
Multi-Object Spectrograph, and the MMT Blue Channel Spectrograph
over a period of roughly 1 year after detection. PS1-11vo is one of
the longest lived, most luminous supernovae (SNe) ever discovered and
the highest quality SN IIn documented by Pan-STARRS1. The Pan-STARRS1
photometric observations indicate maximum was reached roughly 50 days
after the time of explosion, during which the SN rose by approximately
5 mag. Spectra of PS1-11vo display a prominent hydrogen alpha emission
line and P Cygni profile, typical of SNe IIn. We compare the photometric
and spectroscopic observations of PS1-11vo to those of other SNe II,
including several recent ultraluminous SNe IIn. Finally, we examine
its spectral energy distribution to model various parameters of the
SN and its host environment at 5 days past maximum, estimating a peak
luminosity of L = 4.5E43 erg/s and an initial Nickel-56 mass of 4.5
solar masses. This work is supported in part by the NSF REU and DOD
ASSURE programs under NSF grant no. 0754568 and by the Smithsonian
Institution.
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Title: SN 2010ay is a Luminous and Broad-lined Type Ic Supernova
within a Low-metallicity Host Galaxy
Authors: Sanders, N. E.; Soderberg, A. M.; Valenti, S.; Foley,
R. J.; Chornock, R.; Chomiuk, L.; Berger, E.; Smartt, S.; Hurley, K.;
Barthelmy, S. D.; Levesque, E. M.; Narayan, G.; Botticella, M. T.;
Briggs, M. S.; Connaughton, V.; Terada, Y.; Gehrels, N.; Golenetskii,
S.; Mazets, E.; Cline, T.; von Kienlin, A.; Boynton, W.; Chambers,
K. C.; Grav, T.; Heasley, J. N.; Hodapp, K. W.; Jedicke, R.; Kaiser,
N.; Kirshner, R. P.; Kudritzki, R. -P.; Luppino, G. A.; Lupton, R. H.;
Magnier, E. A.; Monet, D. G.; Morgan, J. S.; Onaka, P. M.; Price,
P. A.; Stubbs, C. W.; Tonry, J. L.; Wainscoat, R. J.; Waterson, M. F.
2012ApJ...756..184S Altcode: 2011arXiv1110.2363S
We report on our serendipitous pre-discovery detection and follow-up
observations of the broad-lined Type Ic supernova (SN Ic) 2010ay at
z = 0.067 imaged by the Pan-STARRS1 3π survey just ~4 days after
explosion. The supernova (SN) had a peak luminosity, M<SUB>R</SUB>
≈ -20.2 mag, significantly more luminous than known GRB-SNe and
one of the most luminous SNe Ib/c ever discovered. The absorption
velocity of SN 2010ay is v <SUB>Si</SUB> ≈ 19 × 10<SUP>3</SUP>
km s<SUP>-1</SUP> at ~40 days after explosion, 2-5 times higher than
other broad-lined SNe and similar to the GRB-SN 2010bh at comparable
epochs. Moreover, the velocity declines ~2 times slower than other
SNe Ic-BL and GRB-SNe. Assuming that the optical emission is powered
by radioactive decay, the peak magnitude implies the synthesis of
an unusually large mass of <SUP>56</SUP>Ni, M <SUB>Ni</SUB> = 0.9
M <SUB>⊙</SUB>. Applying scaling relations to the light curve, we
estimate a total ejecta mass, M <SUB>ej</SUB> ≈ 4.7 M <SUB>⊙</SUB>,
and total kinetic energy, E<SUB>K</SUB> ≈ 11 × 10<SUP>51</SUP>
erg. The ratio of M <SUB>Ni</SUB> to M <SUB>ej</SUB> is ~2 times as
large for SN 2010ay as typical GRB-SNe and may suggest an additional
energy reservoir. The metallicity (log (O/H)<SUB>PP04</SUB> + 12 =
8.19) of the explosion site within the host galaxy places SN 2010ay
in the low-metallicity regime populated by GRB-SNe, and ~0.5(0.2)
dex lower than that typically measured for the host environments of
normal (broad-lined) SNe Ic. We constrain any gamma-ray emission
with E <SUB>γ</SUB> <~ 6 × 10<SUP>48</SUP> erg (25-150 keV),
and our deep radio follow-up observations with the Expanded Very Large
Array rule out relativistic ejecta with energy E >~ 10<SUP>48</SUP>
erg. We therefore rule out the association of a relativistic outflow
like those that accompanied SN 1998bw and traditional long-duration
gamma-ray bursts (GRBs), but we place less-stringent constraints on
a weak afterglow like that seen from XRF 060218. If this SN did not
harbor a GRB, these observations challenge the importance of progenitor
metallicity for the production of relativistic ejecta and suggest that
other parameters also play a key role.
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Title: Ultraluminous Supernovae as a New Probe of the Interstellar
Medium in Distant Galaxies
Authors: Berger, E.; Chornock, R.; Lunnan, R.; Foley, R.; Czekala, I.;
Rest, A.; Leibler, C.; Soderberg, A. M.; Roth, K.; Narayan, G.; Huber,
M. E.; Milisavljevic, D.; Sanders, N. E.; Drout, M.; Margutti, R.;
Kirshner, R. P.; Marion, G. H.; Challis, P. J.; Riess, A. G.; Smartt,
S. J.; Burgett, W. S.; Hodapp, K. W.; Heasley, J. N.; Kaiser, N.;
Kudritzki, R. -P.; Magnier, E. A.; McCrum, M.; Price, P. A.; Smith,
K.; Tonry, J. L.; Wainscoat, R. J.
2012ApJ...755L..29B Altcode: 2012arXiv1206.4050B
We present the Pan-STARRS1 discovery and light curves, and follow-up
MMT and Gemini spectroscopy of an ultraluminous supernova (ULSN;
dubbed PS1-11bam) at a redshift of z = 1.566 with a peak brightness
of M <SUB>UV</SUB> ≈ -22.3 mag. PS1-11bam is one of the highest
redshift spectroscopically confirmed SNe known to date. The spectrum
exhibits broad absorption features typical of previous ULSNe (e.g.,
C II, Si III), and strong and narrow Mg II and Fe II absorption lines
from the interstellar medium (ISM) of the host galaxy, confirmed by an
[O II]λ3727 emission line at the same redshift. The equivalent widths
of the Fe II λ2600 and Mg II λ2803 lines are in the top quartile of
the quasar intervening absorption system distribution, but are weaker
than those of gamma-ray burst intrinsic absorbers (i.e., GRB host
galaxies). We also detect the host galaxy in pre-explosion Pan-STARRS1
data and find that its UV spectral energy distribution is best fit
with a young stellar population age of τ<SUB>*</SUB> ≈ 15-45 Myr
and a stellar mass of M <SUB>*</SUB> ≈ (1.1-2.6) × 10<SUP>9</SUP>
M <SUB>⊙</SUB> (for Z = 0.05-1 Z <SUB>⊙</SUB>). The star formation
rate inferred from the UV continuum and [O II]λ3727 emission line is
≈10 M <SUB>⊙</SUB> yr<SUP>-1</SUP>, higher than in previous ULSN
hosts. PS1-11bam provides the first direct demonstration that ULSNe
can serve as probes of the ISM in distant galaxies. The depth and
red sensitivity of PS1 are uniquely suited to finding such events at
cosmologically interesting redshifts (z ~ 1-2); the future combination
of LSST and 30 m class telescopes promises to extend this technique
to z ~ 4.
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Title: An ultraviolet-optical flare from the tidal disruption of a
helium-rich stellar core
Authors: Gezari, S.; Chornock, R.; Rest, A.; Huber, M. E.; Forster, K.;
Berger, E.; Challis, P. J.; Neill, J. D.; Martin, D. C.; Heckman, T.;
Lawrence, A.; Norman, C.; Narayan, G.; Foley, R. J.; Marion, G. H.;
Scolnic, D.; Chomiuk, L.; Soderberg, A.; Smith, K.; Kirshner, R. P.;
Riess, A. G.; Smartt, S. J.; Stubbs, C. W.; Tonry, J. L.; Wood-Vasey,
W. M.; Burgett, W. S.; Chambers, K. C.; Grav, T.; Heasley, J. N.;
Kaiser, N.; Kudritzki, R. -P.; Magnier, E. A.; Morgan, J. S.; Price,
P. A.
2012Natur.485..217G Altcode: 2012arXiv1205.0252G
The flare of radiation from the tidal disruption and accretion of a star
can be used as a marker for supermassive black holes that otherwise lie
dormant and undetected in the centres of distant galaxies. Previous
candidate flares have had declining light curves in good agreement
with expectations, but with poor constraints on the time of disruption
and the type of star disrupted, because the rising emission was not
observed. Recently, two `relativistic' candidate tidal disruption
events were discovered, each of whose extreme X-ray luminosity and
synchrotron radio emission were interpreted as the onset of emission
from a relativistic jet. Here we report a luminous ultraviolet-optical
flare from the nuclear region of an inactive galaxy at a redshift of
0.1696. The observed continuum is cooler than expected for a simple
accreting debris disk, but the well-sampled rise and decay of the light
curve follow the predicted mass accretion rate and can be modelled to
determine the time of disruption to an accuracy of two days. The black
hole has a mass of about two million solar masses, modulo a factor
dependent on the mass and radius of the star disrupted. On the basis of
the spectroscopic signature of ionized helium from the unbound debris,
we determine that the disrupted star was a helium-rich stellar core.
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Title: PAndromeda—First Results from the High-cadence Monitoring
of M31 with Pan-STARRS 1
Authors: Lee, C. -H.; Riffeser, A.; Koppenhoefer, J.; Seitz, S.;
Bender, R.; Hopp, U.; Gössl, C.; Saglia, R. P.; Snigula, J.; Sweeney,
W. E.; Burgett, W. S.; Chambers, K. C.; Grav, T.; Heasley, J. N.;
Hodapp, K. W.; Kaiser, N.; Magnier, E. A.; Morgan, J. S.; Price,
P. A.; Stubbs, C. W.; Tonry, J. L.; Wainscoat, R. J.
2012AJ....143...89L Altcode: 2011arXiv1109.6320L
The Pan-STARRS 1 (PS1) survey of M31 (PAndromeda) is designed to
identify gravitational microlensing events, caused by bulge and
disk stars (self-lensing) and by compact matter in the halos of M31
and the Milky Way (halo lensing or lensing by massive compact halo
objects). With the 7 deg<SUP>2</SUP> field of view (FOV) of PS1, the
entire disk of M31 can be imaged with one single pointing. Our aim
is to monitor M31 with this wide FOV with daily sampling (20 minutes
day<SUP>-1</SUP>). In the 2010 season, we acquired in total 91 nights
toward M31, with 90 nights in the r <SUB>P1</SUB> and 66 nights in
the i <SUB>P1</SUB>. The total integration time in r <SUB>P1</SUB>
and i <SUB>P1</SUB> are 70,740 s and 36,180 s, respectively. As a
preliminary analysis, we study a 40' × 40' sub-field in the central
region of M31, a 20' × 20' sub-field in the disk of M31, and a 20'
× 20' sub-field for the investigation of astrometric precision. We
demonstrate that the point-spread function is good enough to detect
microlensing events. We present light curves for six candidate
microlensing events. This is a competitive rate compared with previous
M31 microlensing surveys. Finally, we also present one example light
curve for Cepheids, novae, and eclipsing binaries in these sub-fields.
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Title: The Photometric Classification Server for Pan-STARRS1
Authors: Saglia, R. P.; Tonry, J. L.; Bender, R.; Greisel, N.; Seitz,
S.; Senger, R.; Snigula, J.; Phleps, S.; Wilman, D.; Bailer-Jones,
C. A. L.; Klement, R. J.; Rix, H. -W.; Smith, K.; Green, P. J.;
Burgett, W. S.; Chambers, K. C.; Heasley, J. N.; Kaiser, N.; Magnier,
E. A.; Morgan, J. S.; Price, P. A.; Stubbs, C. W.; Wainscoat, R. J.
2012ApJ...746..128S Altcode: 2011arXiv1109.5080S
The Pan-STARRS1 survey is obtaining multi-epoch imaging in five bands
(g <SUB>P1</SUB> r <SUB>P1</SUB> i <SUB>P1</SUB> z <SUB>P1</SUB> y
<SUB>P1</SUB>) over the entire sky north of declination -30 deg. We
describe here the implementation of the Photometric Classification
Server (PCS) for Pan-STARRS1. PCS will allow the automatic
classification of objects into star/galaxy/quasar classes based on
colors and the measurement of photometric redshifts for extragalactic
objects, and will constrain stellar parameters for stellar objects,
working at the catalog level. We present tests of the system based on
high signal-to-noise photometry derived from the Medium-Deep Fields
of Pan-STARRS1, using available spectroscopic surveys as training
and/or verification sets. We show that the Pan-STARRS1 photometry
delivers classifications and photometric redshifts as good as the
Sloan Digital Sky Survey (SDSS) photometry to the same magnitude
limits. In particular, our preliminary results, based on this
relatively limited data set down to the SDSS spectroscopic limits,
and therefore potentially improvable, show that stars are correctly
classified as such in 85% of cases, galaxies in 97%, and QSOs in
84%. False positives are less than 1% for galaxies, ≈19% for stars,
and ≈28% for QSOs. Moreover, photometric redshifts for 1000 luminous
red galaxies up to redshift 0.5 are determined to 2.4% precision
(defined as 1.48 × Median|z <SUB>phot</SUB> - z <SUB>spec</SUB>|/(1 +
z)) with just 0.4% catastrophic outliers and small (-0.5%) residual
bias. For bluer galaxies up to the same redshift, the residual bias
(on average -0.5%) trend, percentage of catastrophic failures (1.2%),
and precision (4.2%) are higher, but still interestingly small for
many science applications. Good photometric redshifts (to 5%) can be
obtained for at most 60% of the QSOs of the sample. PCS will create
a value-added catalog with classifications and photometric redshifts
for eventually many millions of sources.
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Title: Ultra-bright Optical Transients are Linked with Type Ic
Supernovae
Authors: Pastorello, A.; Smartt, S. J.; Botticella, M. T.; Maguire,
K.; Fraser, M.; Smith, K.; Kotak, R.; Magill, L.; Valenti, S.; Young,
D. R.; Gezari, S.; Bresolin, F.; Kudritzki, R.; Howell, D. A.; Rest,
A.; Metcalfe, N.; Mattila, S.; Kankare, E.; Huang, K. Y.; Urata,
Y.; Burgett, W. S.; Chambers, K. C.; Dombeck, T.; Flewelling, H.;
Grav, T.; Heasley, J. N.; Hodapp, K. W.; Kaiser, N.; Luppino, G. A.;
Lupton, R. H.; Magnier, E. A.; Monet, D. G.; Morgan, J. S.; Onaka,
P. M.; Price, P. A.; Rhoads, P. H.; Siegmund, W. A.; Stubbs, C. W.;
Sweeney, W. E.; Tonry, J. L.; Wainscoat, R. J.; Waterson, M. F.;
Waters, C.; Wynn-Williams, C. G.
2010ApJ...724L..16P Altcode: 2010arXiv1008.2674P
Recent searches by unbiased, wide-field surveys have uncovered a group
of extremely luminous optical transients. The initial discoveries of
SN 2005ap by the Texas Supernova Search and SCP-06F6 in a deep Hubble
pencil beam survey were followed by the Palomar Transient Factory
confirmation of host redshifts for other similar transients. The
transients share the common properties of high optical luminosities
(peak magnitudes ~-21 to -23), blue colors, and a lack of H or He
spectral features. The physical mechanism that produces the luminosity
is uncertain, with suggestions ranging from jet-driven explosion
to pulsational pair instability. Here, we report the most detailed
photometric and spectral coverage of an ultra-bright transient (SN
2010gx) detected in the Pan-STARRS 1 sky survey. In common with other
transients in this family, early-time spectra show a blue continuum and
prominent broad absorption lines of O II. However, about 25 days after
discovery, the spectra developed type Ic supernova features, showing
the characteristic broad Fe II and Si II absorption lines. Detailed,
post-maximum follow-up may show that all SN 2005ap and SCP-06F6
type transients are linked to supernovae Ic. This poses problems in
understanding the physics of the explosions: there is no indication from
late-time photometry that the luminosity is powered by <SUP>56</SUP>Ni,
the broad light curves suggest very large ejected masses, and the slow
spectral evolution is quite different from typical Ic timescales. The
nature of the progenitor stars and the origin of the luminosity are
intriguing and open questions.
---------------------------------------------------------
Title: GALEX and Pan-STARRS1 Discovery of SN IIP 2010aq: The First
Few Days After Shock Breakout in a Red Supergiant Star
Authors: Gezari, S.; Rest, A.; Huber, M. E.; Narayan, G.; Forster,
K.; Neill, J. D.; Martin, D. C.; Valenti, S.; Smartt, S. J.; Chornock,
R.; Berger, E.; Soderberg, A. M.; Mattila, S.; Kankare, E.; Burgett,
W. S.; Chambers, K. C.; Dombeck, T.; Grav, T.; Heasley, J. N.; Hodapp,
K. W.; Jedicke, R.; Kaiser, N.; Kudritzki, R.; Luppino, G.; Lupton,
R. H.; Magnier, E. A.; Monet, D. G.; Morgan, J. S.; Onaka, P. M.;
Price, P. A.; Rhoads, P. H.; Siegmund, W. A.; Stubbs, C. W.; Tonry,
J. L.; Wainscoat, R. J.; Waterson, M. F.; Wynn-Williams, C. G.
2010ApJ...720L..77G Altcode: 2010arXiv1007.4551G
We present the early UV and optical light curve of Type IIP supernova
(SN) 2010aq at z = 0.0862, and compare it to analytical models for
thermal emission following SN shock breakout in a red supergiant
star. SN 2010aq was discovered in joint monitoring between the Galaxy
Evolution Explorer (GALEX) Time Domain Survey (TDS) in the NUV and
the Pan-STARRS1 Medium Deep Survey (PS1 MDS) in the g, r, i, and z
bands. The GALEX and Pan-STARRS1 observations detect the SN less than
1 day after the shock breakout, measure a diluted blackbody temperature
of 31, 000 ± 6000 K 1 day later, and follow the rise in the UV/optical
light curve over the next 2 days caused by the expansion and cooling of
the SN ejecta. The high signal-to-noise ratio of the simultaneous UV
and optical photometry allows us to fit for a progenitor star radius
of 700 ± 200R <SUB>sun</SUB>, the size of a red supergiant star. An
excess in UV emission two weeks after shock breakout compared with
SNe well fitted by model atmosphere-code synthetic spectra with solar
metallicity is best explained by suppressed line blanketing due to a
lower metallicity progenitor star in SN 2010aq. Continued monitoring
of PS1 MDS fields by the GALEX TDS will increase the sample of early
UV detections of Type II SNe by an order of magnitude and probe the
diversity of SN progenitor star properties.
---------------------------------------------------------
Title: Supernova 2009kf: An Ultraviolet Bright Type IIP Supernova
Discovered with Pan-STARRS 1 and GALEX
Authors: Botticella, M. T.; Trundle, C.; Pastorello, A.; Rodney,
S.; Rest, A.; Gezari, S.; Smartt, S. J.; Narayan, G.; Huber, M. E.;
Tonry, J. L.; Young, D.; Smith, K.; Bresolin, F.; Valenti, S.; Kotak,
R.; Mattila, S.; Kankare, E.; Wood-Vasey, W. M.; Riess, A.; Neill,
J. D.; Forster, K.; Martin, D. C.; Stubbs, C. W.; Burgett, W. S.;
Chambers, K. C.; Dombeck, T.; Flewelling, H.; Grav, T.; Heasley, J. N.;
Hodapp, K. W.; Kaiser, N.; Kudritzki, R.; Luppino, G.; Lupton, R. H.;
Magnier, E. A.; Monet, D. G.; Morgan, J. S.; Onaka, P. M.; Price,
P. A.; Rhoads, P. H.; Siegmund, W. A.; Sweeney, W. E.; Wainscoat,
R. J.; Waters, C.; Waterson, M. F.; Wynn-Williams, C. G.
2010ApJ...717L..52B Altcode: 2010arXiv1001.5427B
We present photometric and spectroscopic observations of a luminous
Type IIP Supernova (SN) 2009kf discovered by the Pan-STARRS 1 (PS1)
survey and also detected by the Galaxy Evolution Explorer. The SN
shows a plateau in its optical and bolometric light curves, lasting
approximately 70 days in the rest frame, with an absolute magnitude
of M <SUB> V </SUB> = -18.4 mag. The P-Cygni profiles of hydrogen
indicate expansion velocities of 9000 km s<SUP>-1</SUP> at 61 days
after discovery which is extremely high for a Type IIP SN. SN 2009kf
is also remarkably bright in the near-ultraviolet (NUV) and shows a
slow evolution 10-20 days after optical discovery. The NUV and optical
luminosity at these epochs can be modeled with a blackbody with a
hot effective temperature (T ~ 16,000 K) and a large radius (R ~
1 × 10<SUP>15</SUP> cm). The bright bolometric and NUV luminosity,
the light curve peak and plateau duration, the high velocities,
and temperatures suggest that 2009kf is a Type IIP SN powered by a
larger than normal explosion energy. Recently discovered high-z SNe
(0.7 < z < 2.3) have been assumed to be IIn SNe, with the
bright UV luminosities due to the interaction of SN ejecta with a
dense circumstellar medium. UV-bright SNe similar to SN 2009kf could
also account for these high-z events, and its absolute magnitude M
<SUB>NUV</SUB> = -21.5 ± 0.5 mag suggests such SNe could be discovered
out to z ~ 2.5 in the PS1 survey.
---------------------------------------------------------
Title: NStED: XO Project Data Release 1 (XO-DR1)
Authors: McCullough, P. R.; Stys, J. E.; Valenti, J. A.; Fleming,
S. W.; Jane, K. A.; Heasley, J. N.
2009nsted.cat....7M Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The Pan-STARRS Data Processing and Science Analysis Software
Systems
Authors: Heasley, J. N.
2008AIPC.1082..352H Altcode:
The Panoramic Survey Telescope and Rapid Response System (Pan-STARRS)
will use gigapixel CCD cameras on multiaperture telescopes to survey
the sky in the visible and infrared bands. A single telescope system
(PS1) has been deployed on Maui, and a four-telescope system (PS4)
will be sited on Mauna Kea on the Big Island of Hawaii. These systems
will survey the sky repeatedly and will generate petabytes of image data
and catalogs of billions of stars and galaxies. Each set of images will
be combined to create a very sensitive multicolor image of the sky,
and differences between images will provide for a massive database of
“time domain astronomy” including the study of moving objects and
transient or variable objects. All data from PS1 will be put into
the public domain following its 3.5 year survey. The project faces
formidable challenges in processing the image data in near real time
and making the catalog data accessible via relational databases. In
this talk, I describe the software systems developed by the Pan-STARRS
project and how these core systems will be augmented by an assortment
of science “servers” being developed by astronomers in the PS1
Science Consortium.
---------------------------------------------------------
Title: XO-3b: A Massive Planet in an Eccentric Orbit Transiting an
F5 V Star
Authors: Johns-Krull, Christopher M.; McCullough, Peter R.; Burke,
Christopher J.; Valenti, Jeff A.; Janes, K. A.; Heasley, J. N.; Prato,
L.; Bissinger, R.; Fleenor, M.; Foote, C. N.; Garcia-Melendo, E.;
Gary, B. L.; Howell, P. J.; Mallia, F.; Masi, G.; Vanmunster, T.
2008ApJ...677..657J Altcode: 2007arXiv0712.4283J
We report the discovery of a massive planet (M<SUB>p</SUB>sin i = 13.02
+/- 0.64 M<SUB>J</SUB>; total mass = 13.25 +/- 0.64 M<SUB>J</SUB>),
large (1.95 +/- 0.16 R<SUB>J</SUB>) planet in a transiting, eccentric
orbit (e = 0.260 +/- 0.017) around a 10th magnitude F5 V star in the
constellation Camelopardalis. We designate the planet XO-3b and the
star XO-3, also known as GSC 03727-01064. The orbital period of XO-3b
is 3.1915426 +/- 0.00014 days. XO-3 lacks a trigonometric parallax; we
estimate its distance to be 260 +/- 23 pc. The radius of XO-3 is 2.13
+/- 0.21 R<SUB>⊙</SUB>, its mass is 1.41 +/- 0.08 M<SUB>⊙</SUB>,
its vsin i = 18.54 +/- 0.17 km s<SUP>-1</SUP>, and its metallicity is
[ Fe/H ] = - 0.177 +/- 0.027. This system is unusual for a number of
reasons. XO-3b is one of the most massive planets discovered around
any star for which the orbital period is less than 10 days. The
mass is near the deuterium-burning limit of 13 M<SUB>J</SUB>, which
is a proposed boundary between planets and brown dwarfs. Although
Burrows et al. propose that formation in a disk or formation in the
interstellar medium in a manner similar to stars is a more logical way
to differentiate planets and brown dwarfs, our current observations
are not adequate to address this distinction. XO-3b is also unusual
in that its eccentricity is large given its relatively short orbital
period. Both the planetary radius and the inclination are functions
of the spectroscopically determined stellar radius. Analysis of the
transit light curve of XO-3b suggests that the spectroscopically derived
parameters may be overestimated. Though relatively noisy, the light
curves favor a smaller radius in order to better match the steepness of
the ingress and egress. The light curve fits imply a planetary radius of
1.25 +/- 0.15 R<SUB>J</SUB>, which would correspond to a mass of 12.03
+/- 0.46 M<SUB>J</SUB>. A precise trigonometric parallax measurement
or a very accurate light curve is needed to resolve the uncertainty
in the planetary mass and radius.
---------------------------------------------------------
Title: XO-2b: Transiting Hot Jupiter in a Metal-rich Common Proper
Motion Binary
Authors: Burke, Christopher J.; McCullough, P. R.; Valenti, Jeff A.;
Johns-Krull, Christopher M.; Janes, Kenneth A.; Heasley, J. N.;
Summers, F. J.; Stys, J. E.; Bissinger, R.; Fleenor, Michael L.;
Foote, Cindy N.; García-Melendo, Enrique; Gary, Bruce L.; Howell,
P. J.; Mallia, F.; Masi, G.; Taylor, B.; Vanmunster, T.
2007ApJ...671.2115B Altcode: 2007arXiv0705.0003B
We report on a V=11.2 early K dwarf, XO-2 (GSC 03413-00005),
that hosts a R<SUB>p</SUB>=0.98+/-<SUP>0.03</SUP><SUB>0.01</SUB>
R<SUB>J</SUB>, M<SUB>p</SUB>=0.57+/-0.06 M<SUB>J</SUB> transiting
extrasolar planet, XO-2b, with an orbital period of 2.615857+/-0.000005
days. XO-2 has high metallicity, [Fe/H]=0.45+/-0.02, high proper
motion, μ<SUB>tot</SUB>=157 mas yr<SUP>-1</SUP>, and a common proper
motion stellar companion with 31" separation. The two stars are nearly
identical twins, with very similar spectra and apparent magnitudes. Due
to the high metallicity, these early K dwarf stars have a mass and
radius close to solar, M<SUB>*</SUB>=0.98+/-0.02 M<SUB>solar</SUB>
and R<SUB>*</SUB>=0.97+/-<SUP>0.02</SUP><SUB>0.01</SUB>
R<SUB>solar</SUB>. The high proper motion of XO-2 results from an
eccentric orbit (Galactic pericenter, R<SUB>per</SUB><4 kpc) well
confined to the Galactic disk (Z<SUB>max</SUB>~100 pc). In addition,
the phase-space position of XO-2 is near the Hercules dynamical stream,
which points to an origin of XO-2 in the metal-rich, inner thin disk
and subsequent dynamical scattering into the solar neighborhood. We
describe an efficient Markov chain Monte Carlo algorithm for calculating
the Bayesian posterior probability of the system parameters from a
transit light curve.
---------------------------------------------------------
Title: The PS1 Software Systems
Authors: Heasley, James N.; Jedicke, R.; Magnier, E.
2007AAS...211.4717H Altcode: 2007BAAS...39..806H
The Pan-STARRS PS1 observatory will generate on average 1.4 TBytes of
image data during a typical night of observing. To support the reduction
and analysis of these data, the Pan-STARRS construction project has
developed three software systems: the Image Processing Pipeline (IPP)
for the reduction and calibration of the images and the generation of
source catalogs, the Moving Object Processing System (MOPS), a science
client designed to develop orbital information for the moving transient
sources found by the IPP, and the Published Science Products Subsystem
(PSPS) which will serve as the scientific access point to the catalog
data derived by the IPP and as the overall archive for the science
products generated by PS1. The IPP has largely been developed internally
at the Institute for Astronomy. The software has been extensively
tested on CCD mosaic data from the CFH12K, MegaPrime, and Suprime
cameras. Since late August 2007 we have been using IPP to process the
first images from the PS1 gigapixel camera. MOPS incorporates both
legacy code and new software developed for linking observations of
objects on different nights into tracklets for orbit determination. The
MOPS has been tested with simulations based on our model of the solar
system as well as on data from the SpaceWatch observatory. The primary
component of the PSPS is the Object Data Manager (ODM) which will
serve as the science database for the stationary objects found in the
PS1 observations. We anticipate tracking over 5.5 billion objects and
140 billion detections over the 3.5 year mission of PS1. The ODM is
leveraging the design work done during the Sloan Digital Sky Survey
to scale out a database design to accommodate this volume of data.
---------------------------------------------------------
Title: Mass Determinations of Population II Binary Stars
Authors: Williamson, Kathryn; Heasley, J. N.
2007AAS...21113101W Altcode: 2007BAAS...39..958W
Accurate mass determinations of Population II stars are essential to
understanding the metallicity effects in stellar evolutionary models
of the old stars in the Galactic halo. This research contributes
accurate mass estimates for the three dwarf Population II binary
systems HD 157948, HD 195987, and HD 200580. Results were obtained via
a simultaneous least-squares adjustment of double-line spectroscopic and
astrometric data to find the best fit orbital parameters and masses with
error estimates. Monte Carlo simulations of theoretical data sets were
used to test the consistency and accuracy of the optimization techniques
in order to gauge the reliability of results. These theoretical data
were designed to match orbital parameters that likely describe the three
binary systems of this study. The results of the Monte Carlo analysis
imply that reported mass estimates and error bars are indeed reliable
for each particular orbit and given set of observation times. These
reported masses can, therefore, effectively contribute to a Population
II Mass-Luminosity Relationship. This work was conducted during a
Research Experience for Undergraduates (REU) at the University of
Hawaii's Institute for Astronomy and funded by the NSF.
---------------------------------------------------------
Title: The Unusual Transiting Extra-Solar Planet Orbiting XO-3
Authors: Johns-Krull, Christopher M.; McCullough, P. M.; Burke,
C. J.; Valenti, J. A.; Janes, K. A.; Heasley, J. N.; Bissinger, R.;
Fleenor, M.; Foote, C. N.; Garcia-Melendo, E.; Gary, B. L.; Howell,
P. J.; Mallia, F.; Masi, G.; Prato, L. A.; Vanmunster, T.
2007AAS...210.9605J Altcode:
We report the discovery of a massive planet (≈12 M<SUB>JUP</SUB>)
in an eccentric orbit (e ≈ 0.2) around the F6 star XO-3. This planet
transits the 10<SUP>th</SUP> magnitude star every 3.19 days. This
system is unusual for a number of reasons. XO-3b is one of the most
massive planets discovered around any star for which the orbital period
is less than 10 days. The mass is near the deuterium burning limit of
13 M<SUB>JUP</SUB> which is a proposed boundary between planets and
brown dwarfs. Burrows et al. (2001) propose that formation in a disk
or formation in the interstellar medium in a manner similar to stars
is a more logical way to differentiate planets and brown dwarfs. Our
current observations are not adequate to address this distinction. XO-3b
is also unusual in that its eccentricity is large given its relatively
short orbital period. Finally, the star XO-3 is somewhat metal poor,
with [Fe/H] ≈ -0.25. We will present our observations leading to
this discovery and discuss the implications of this system for models
of planet formation.
---------------------------------------------------------
Title: XO-2b: A Transiting Hot Jupiter in a Metal-rich Common Proper
Motion Binary
Authors: Burke, Christopher J.; McCullough, P. R.; Valenti, J. A.;
Summers, F. J.; Stys, J. E.; Johns-Krull, C. M.; Janes, K. A.; Heasley,
J. N.; Bissinger, R.; Fleenor, M.; Foote, C. N.; Garcia-Melendo, E.;
Gary, B. L.; Howell, P. J.; Mallia, F.; Masi, G.; Vanmunster, T.
2007AAS...210.3302B Altcode: 2007BAAS...39Q.145B
XO-2b, the second transiting extrasolar planet from the XO Project
(McCullough et al. 2005), is approximately Jupiter-size and 0.6
Jupiter-mass with an orbital period of 2.6 days. The stellar host, XO-2,
is a V=11.2, early K dwarf which is metal rich, [Fe/H]=+0.44. XO-2
has a high proper motion, 157 mas/yr, and has a common proper motion
stellar companion with half arcmin separation. The two stars are nearly
identical twins, with very similar spectra and apparent magnitudes. The
global network of amateur and professional astronomers organized by the
XO project confirmed the XO-2b transit light curve two days after being
notified that it was a high-priority candidate, and radial velocities
confirmed its planetary mass eight days after that.
---------------------------------------------------------
Title: The Pan-STARRS Object Data Manager Database
Authors: Heasley, James N.; Nieto-Santisteban, M.; Szalay, A.;
Thakar, A.
2007AAS...210.2103H Altcode: 2007BAAS...39..124H
The Panoramic Survey Telescope and Rapid Response System (Pan-STARRS)
project is an observing system to support wide-field survey observing
programs for a multitude of scientific objectives. The composite images
of the sky that will be produced over the 3.5 year mission of the
PS-1 prototype telescope are expected to yield over 5 billion distinct
objects. A significant fraction of these sources will be measured up
60 times through filters on the Sloan g, r, i, z, and y system thus
providing information on their time history. <P />A major challenge
for the Pan-STARRS project has been the design of our database, the
Object Data Manager (ODM), that will keep track of the catalogs of
these objects in the stationary sky, their associated time-history of
detections, and provide an interface that will allow users to access
these data. The ODM is a key component of the Pan-STARRS Published
Sciences Products Subsystem (PSPS). In this poster we describe the
the challenges presented by the ODM design, how it fits into the PSPS,
and the prototype design we are working on to build an ODM that will
handle an order of magnitude more distinct objects found in either
the SDSS or 2MASS surveys.
---------------------------------------------------------
Title: A Transiting Planet of a Sun-like Star
Authors: McCullough, P. R.; Stys, J. E.; Valenti, Jeff A.; Johns-Krull,
C. M.; Janes, K. A.; Heasley, J. N.; Bye, B. A.; Dodd, C.; Fleming,
S. W.; Pinnick, A.; Bissinger, R.; Gary, B. L.; Howell, P. J.;
Vanmunster, T.
2006ApJ...648.1228M Altcode: 2006astro.ph..5414M
A planet transits an 11th magnitude, G1 V star in the constellation
Corona Borealis. We designate the planet XO-1b and the star XO-1,
also known as GSC 02041-01657. XO-1 lacks a trigonometric distance;
we estimate it to be 200+/-20 pc. Of the 10 stars currently
known to host extrasolar transiting planets, the star XO-1 is
the most similar to the Sun in its physical characteristics: its
radius is 1.0+/-0.08 R<SUB>solar</SUB>, its mass is 1.0+/-0.03
M<SUB>solar</SUB>, its Vsini<3 km s<SUP>-1</SUP>, and its
metallicity [Fe/H] is 0.015+/-0.04. The orbital period of the planet
XO-1b is 3.941534+/-0.000027 days, one of the longer ones known. The
planetary mass is 0.90+/-0.07M<SUB>J</SUB>, which is marginally
larger than that of other transiting planets with periods between
3 and 4 days. Both the planetary radius and the inclination are
functions of the spectroscopically determined stellar radius. If the
stellar radius is 1.0+/-0.08 R<SUB>solar</SUB>, then the planetary
radius is 1.30+/-0.11R<SUB>J</SUB> and the inclination of the orbit
is 87.7d+/-1.2d. We have demonstrated a productive international
collaboration between professional and amateur astronomers that
was important to distinguishing this planet from many other similar
candidates.
---------------------------------------------------------
Title: Fourier Analysis of Hubble Space Telescope Fine Guidance Sensor
Data of Binary Stars and Application to the Multiple System HD 157948
Authors: Horch, Elliott P.; Franz, Otto G.; Wasserman, Lawrence H.;
Heasley, James N.
2006AJ....132..836H Altcode:
A Fourier-based method is presented for the analysis of binary and
multiple star data taken with the Hubble Space Telescope Fine Guidance
Sensors (FGSs). Relative astrometry and magnitude differences are
obtained as with standard FGS analysis techniques, and although the
FGS system is essentially unfiltered, this method also permits the
characterization of color differences between components of binary
or multiple star systems based on the wavelength dependence of the
interference fringes produced by the instrument. Using the multiple
system HD 157948, we show that the method produces astrometric and
photometric measurements that are consistent with previous FGS analysis
for the three components that lie within the field of view of FGS and
gives color differences relative to the primary for two of the three
known companions. Speckle observations of the system with the WIYN 3.5 m
telescope at Kitt Peak National Observatory are also presented, which,
in combination with the FGS results and other data available in the
literature, permit B-V colors and absolute V magnitudes to be obtained
of all four components in the system. Their colors and magnitudes are
plotted on the H-R diagram, and a comparison with theoretical isochrones
indicates that the results are consistent with theory for a relatively
young, somewhat metal-poor system. <P />Based on observations made with
the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope
Science Institute, which is operated by the Association of Universities
for Research in Astronomy, Inc., under NASA contract NAS5-26555.
---------------------------------------------------------
Title: A New Algorithm for Multiple Hypothesis-based Tracking and
Discovery of Potentially Hazardous Near Earth Objects
Authors: Palaniappan, A.; Heasley, J. N.; Uhlmann, J. K.; Palaniappan,
K.
2005AAS...20715403P Altcode: 2005BAAS...37R1414P
The success of the Pan-STARRS NEO discovery program, will critically
depend upon the automatic tracking of millions of observations,
with the full sky covered on a monthly basis. Manual analysis and
tracking of millions of NEO observations is not only rate limiting,
but also highly error prone. Methods for fully automatic tracking of
NEOs, which is similar to the missile-tracking problem, are being
actively investigated. A new adjusted Kalman filter-based linear
prediction and error model, is proposed for fast Mahalanobis-distance
based gating using the KD-tree data structure, multiple hypothesis
track pruning, and track assignment using a tree data structure. Our
results using the novel (T,I) celestial coordinate system shows over
99% accuracy in correct pair-wise track associations for the same
night observations, and remarkably over the longer four-night epochs,
performance does not degrade as it does using other standard celestial
coordinate systems including (α ,δ ), (λ ,β ), or (x,y,z). The (T,I)
coordinates have a more linear behavior and so the Kalman predictions
are more accurate. However, the Kalman prediction errors are biased and
skewed. A new adjusted Kalman filter model is introduced to recursively
incorporate the actual prediction error statistics using the test
data. The multiple hypothesis tree containing all feasible tracks at
the final epoch of tracking has over a 90% success rate in finding
the correct asteroid associations within the top 30 tracks as ranked
in terms of the average along track Mahalanobis distance. Future work
includes incorporating joint assignment to prune the tree, and the use
of a non-linear elliptical orbit prediction model combined with Monte
Carlo covariance estimation methods to eliminate false tracks from
the final set of long associations. Both of these extensions should
further improve performance towards achieving automatic multi-target
tracking of millions of asteroids.
---------------------------------------------------------
Title: Pan-STARRS: Main Belt Sky-Plane Density Determination, and
Trailed Object Identification
Authors: Masiero, J. R.; Jedicke, R.; Price, P. A.; Magnier, E. A.;
Heasley, J. N.
2005AAS...20712104M Altcode: 2005BAAS...37R1363M
The sky-plane density of Main Belt objects is one of the main factors
required to estimate the number of moving objects Pan-STARRS will be
able to observe and identify. The Main Belt dominates all other classes
of asteroids in magnitude-limited surveys, thus calculating the number
per square degree of Main Belt objects on the ecliptic will allow us
to precisely estimate the number of moving objects Pan-STARRS will
discover. To this end, we have used 15 deg<SUP>2</SUP> of CFHT-MegaCam
data to simulate 2 Pan-STARRS fields of view. We have searched these
data for all moving objects, using a pipeline very similar to the
one that will be employed by Pan-STARRS' Image Processing Pipeline
(IPP). To calculate true sky-plane density, we have generated artificial
moving objects and planted them in our images, allowing us to directly
determine the efficiency of our pipeline. <P />We have also performed
a similar efficiency analysis for trailed objects of varying lengths,
to test our trailed object fitting algorithms and determine if there
is a variance with length or brightness.
---------------------------------------------------------
Title: The XO Project: Searching for Transiting Extrasolar Planet
Candidates
Authors: McCullough, P. R.; Stys, J. E.; Valenti, J. A.; Fleming,
S. W.; Janes, K. A.; Heasley, J. N.
2005PASP..117..783M Altcode: 2005astro.ph..5560M
The XO project's first objective is to find hot Jupiters transiting
bright stars (i.e., V<12) by precision differential photometry. Two
XO cameras have been operating since 2003 September on the 10,000
foot Haleakala summit on Maui. Each XO camera consists of a 200
mm f/1.8 lens coupled to a 1024×1024 pixel, thinned CCD operated
by drift-scanning. In its first year of routine operation, XO has
observed 6.6% of the sky within six 7° wide strips scanned from 0°
to +63° of declination and centered at R.A. = 0, 4, 8, 12, 16, and 20
hr. Autonomously operating, XO records 1 billion pixels per clear night,
calibrates them photometrically and astrometrically, performs aperture
photometry, archives the pixel data, and transmits the photometric data
to the Space Telescope Science Institute for further analysis. From the
first year of operation, the resulting database consists of photometry
of ~100,000 stars at more than 1000 epochs per star, with differential
photometric precision better than 1% per epoch. Analysis of the light
curves of those stars produces transiting-planet candidates requiring
detailed follow-up, described elsewhere, culminating in spectroscopy
to measure radial velocity variation in order to differentiate genuine
planets from the more numerous impostors, primarily eclipsing binary
and multiple stars.
---------------------------------------------------------
Title: Pan-STARRS: A Large Synoptic Survey Telescope Array
Authors: Kaiser, Nicholas; Aussel, Herve; Burke, Barry E.; Boesgaard,
Hans; Chambers, Ken; Chun, Mark R.; Heasley, James N.; Hodapp,
Klaus-Werner; Hunt, Bobby; Jedicke, Robert; Jewitt, D.; Kudritzki,
Rolf; Luppino, Gerard A.; Maberry, Michael; Magnier, Eugene; Monet,
David G.; Onaka, Peter M.; Pickles, Andrew J.; Rhoads, Pui Hin H.;
Simon, Theodore; Szalay, Alexander; Szapudi, Istvan; Tholen, David J.;
Tonry, John L.; Waterson, Mark; Wick, John
2002SPIE.4836..154K Altcode:
The IFA and collaborators are embarking on a project to develop
a 4-telescope synoptic survey instrument. While somewhat smaller
than the 6.5m class telescope envisaged by the decadal review in
their proposal for a LSST, this facility will nonetheless be able
to accomplish many of the LSST science goals. In this paper we will
describe the motivation for a ‘distributed aperture" approach for
the LSST, the current concept for Pan-STARRS -- a pilot project for
the LSST proper -- and its performance goals and science reach. We
will also discuss how the facility may be expanded.
---------------------------------------------------------
Title: Physical Parameters of the Metal-Poor Binary System HD 157948
Authors: Heasley, J. N.; Franz, O. G.; Wasserman, L. H.; Horch, E. P.
2002AAS...201.0403H Altcode: 2002BAAS...34.1095H; 2002AAS...201..403H
The metal-poor star HD 157948 ([Fe/H] = -0.75]) has been identified by
Latham et al. (1992, A.J., 104, 774) as a doubled-lined spectroscopic
binary with a period of 446.7 days. We have observed this star 5 times
using the FGS on the Hubble Space Telescope as part of a program to
determine the masses and luminosities of Population II stars. The
FGS observations resolve HD 157948 into a triple-star system, with
a close pair that corresponds to the spectroscopic double and wide
fainter component. The tight inner pair has a projected orbit with a
semi-major axis of 20 mas and exhibits orbital motion consistent with
the period determined from the spectroscopic observations. This pair
has a magnitude difference of 0.4 as measured through the F583W filter
on the FGS. The faint, distant component is 280 mas from the primary
star and is 2.3 magnitudes fainter. The wide componet has also been
resolved at several wavelengths using the WIYN telescope. In this paper
we present the physical parameters for the tight pair derived from a
preliminary analysis of the HST astrometry combined with the radial
velocity data from the literature. This work is based on observations
made with the NASA/ESA Hubble Space Telescope, obtained at the Space
Telescope Science Institute, which is operated by the Association of
Universities for Research in Astronomy, Inc., under NASA contract NAS
5-26555. These observations are associated with proposal # 9034.
---------------------------------------------------------
Title: Fourier Analysis of Fine Guidance Sensor Transfer Scans
Authors: Robinson, S. E.; Horch, E. P.; Franz, O. G.; Wasserman,
L. H.; Heasley, J. N.
2002AAS...200.0813R Altcode: 2002BAAS...34..655R
We have developed a Fourier analysis technique for resolving close
binary stars with the Fine Guidance Sensor system of the Hubble Space
Telescope. Transfer mode scans are segmented into the individual passes
and autocorrelated, and then a summed autocorrelation is formed for each
observation. High resolution information is then obtained by Fourier
deconvolution using a single star template autocorrelation. The method
is described and preliminary results are presented for certain known
spectroscopic binaries. Potential limitations of the method are also
discussed. This work is based on observations made with the NASA/ESA
Hubble Space Telescope, obtained at the Space Telescope Science
Institute, which is operated by the Association of Universities for
Research in Astronomy, Inc., under NASA contract NAS 5-26555. These
observations are associated with proposal # 9034.
---------------------------------------------------------
Title: M31 Globular Clusters in the Near-Infrared
Authors: Brandner, Wolfgang; Tully, R. Brent; Heasley, James N.
2002IAUS..207..152B Altcode:
We have observed the M31 globular clusters with the University of Hawaii
Adaptive Optics System Hokupa`a at the Gemini North 8m telescope on
Mauna Kea. This is part of a project which aims at spatially resolving
intermediate-age and old-age stellar populations in the Local Volume and
beyond - possibly out to distances of the Virgo and Fornax clusters. The
sparse M31 globular cluster G27 (Hubble 6) is for the first time
resolved into individual stars. The tip of the red giant branch (TRGB)
at K≈18.8mag yields a metallicity of Z around 0.001 solar for G27.
---------------------------------------------------------
Title: Using Stardial in the Classroom
Authors: Dietz, R. D.; McCullough, P. R.; Richmond, M. W.; Heasley,
J. N.
2000AAS...197.8710D Altcode: 2000BAAS...32R1556D
Stardial is an autonomous astronomical camera on the World Wide
Web. From its roof-top location facing the meridian at the University
of Illinois it captures a drift-scan image of the equatorial sky
every 15 minutes, all night, every night. These images are immediately
available at http://stardial.com/. Since its inception in July of 1996,
Stardial has captured and archived some 69,000 images containing stars,
galaxies, planets, asteroids, comets, meteors, satellites, airplanes,
and many, many clouds. Several hundred measurable variable stars are
found in the seven percent of the sky patrolled by Stardial. This
data set represents an unprecedented resource to be exploited in
the teaching of astronomy. We report on our experiences in using
Stardial data as a tool for instruction in astronomy at four different
universities. Selected Stardial images, class assignments, and student
projects will be displayed.
---------------------------------------------------------
Title: Hubble Space Telescope Photometry of the Metal-rich Globular
Clusters NGC 6624 and NGC 6637
Authors: Heasley, J. N.; Janes, K. A.; Zinn, Robert; Demarque, Pierre;
Da Costa, Gary S.; Christian, Carol A.
2000AJ....120..879H Altcode:
We have observed the metal-rich globular clusters NGC 6624 and NGC
6637 (M69) using the planetary camera of the WFPC2 on the Hubble Space
Telescope (HST). Observations of the Ca II triplet lines in giant stars
in these clusters show that NGC 6624 and NGC 6637 have metallicities
on the Zinn and West scale of [Fe/H]=-0.63+/-0.09 and -0.65+/-0.09,
only slightly more metal rich than 47 Tuc [Fe/H]=-0.71+/-0.07. For
clusters of identical (or nearly so) metallicity, one can make a direct
comparison of the color-magnitude diagrams to derive the relative ages
of the clusters. From the color-magnitude diagrams derived from the HST
photometry, we find that NGC 6624 and NGC 6637 differ in age by less
than 0.5 Gyr. Their color-magnitude diagrams are also compared with
those of 47 Tuc and NGC 6352, and while these latter diagrams are of
somewhat lower quality, they are consistent with all of these clusters
having the same ages. Adopting an apparent distance modulus of 13.40 and
reddening E(B-V)=0.04 for 47 Tuc, the new Yale isochrones yield an age
for the clusters of 14 Gyr. The positions of NGC 6624 and NGC 6637 in
the Galaxy suggest that they belong to the bulge population of globular
clusters. The only other bulge clusters that have been dated so far are
the more metal rich clusters NGC 6528 and NGC 6553, which also appear
to be very old. Consequently, the age-metallicity relation of the bulge
may be very steep. The close similarity of the ages and metallicities
of NGC 6624 and NGC 6637 to the thick-disk globular clusters 47 Tuc
and NGC 6352 indicates that the age-metallicity relations of these
populations intersect. We briefly discuss the possibility that these
populations had a common origin. Based on observations made with the
Anglo-Australian Telescope, Canada-France-Hawaii Telescope, and the
NASA/ESA Hubble Space Telescope. The observations from the Hubble Space
Telescope were obtained from the Space Telescope Science Institute,
which is operated by the Association of Universities for Research in
Astronomy, Inc., under NASA contract NAS5-26555.
---------------------------------------------------------
Title: VizieR Online Data Catalog: Optical/IR observ. of Radio
Galaxies and QSOs (Dunlop+, 1989)
Authors: Dunlop, J. S.; Peacock, J. A.; Savage, A.; Lilly, S. J.;
Heasley, J. N.; Simon, A. J. B.
1999yCat..72381171D Altcode:
This catalog reports on an extensive optical and infrared study of the
178 radio sources in the Parkes Selected Regions (S > 100 mJy at
2.7 GHz). CCD observations have resulted in the essential completion
(95 percent) of optical identifications and have provided B and R
photometry. In addition, K photometry has been completed for four of
the six selected regions. (2 data files).
---------------------------------------------------------
Title: Point-Spread Function Fitting Photometry
Authors: Heasley, J. N.
1999ASPC..189...56H Altcode: 1999pcp..conf...56H
No abstract at ADS
---------------------------------------------------------
Title: Stardial as an Instructional Tool
Authors: Dietz, R. D.; Heasley, J. N.; McCullough, P. R.
1998AAS...193.3404D Altcode: 1998BAAS...30.1293D
Stardial is an autonomous astronomical camera on the world wide web
(WWW). From its roof-top location facing the meridian at the University
of Illinois it captures a drift-scan image of the equatorial sky every
fifteen minutes, all night, every night. These images are immediately
available on the WWW (www.astro.uiuc.edu/stardial/). Since its inception
in July of 1996 Stardial has captured and archived some 37,000 images
containing stars, galaxies, planets, asteroids, comets, meteors,
satellites, airplanes, and many clouds. Several hundred measurable
variable stars are found in the seven percent of the sky patrolled
by Stardial. This data set represents an unprecedented resource to be
exploited in the teaching of astronomy. We report on our experiences
in using Stardial data as a tool for instruction in astronomy at three
different universities. We display selected Stardial images, class
assignments, and student projects. Finally, we discuss the feasibility
and the motivation for a network of Stardial cameras. Interested
parties are invited to contact us at the meeting or by email.
---------------------------------------------------------
Title: The Prospects for Asteroseismology from Ground-based Sites
Authors: Heasley, J. N.; Janes, Kenneth; Labonte, Barry; Guenther,
David; Mickey, Donald; Demarque, Pierre
1996PASP..108..385H Altcode:
We reexamine the possibility of detecting p-mode oscillations in
Sun-like stars with ground-based telescopes. Previous attempts to
make such observations with photometric techniques have been limited
to subgiant stars in M67 and have illustrated the great difficulties
involved in performing ground-based asteroseismology. Substantial gains
in observing efficiency can be realized from new diagnostic techniques
and improvements in instrumentation, especially with newer CCD camera
systems. We show that for appropriately selected field stars observed
with a network of telescopes or at a high duty cycle site, it will be
possible to detect p-mode oscillations from the ground. An alternative
to a network of telescopes for asteroseismology would be to develop a
dedicated observatory for this purpose at a high duty cycle site, i.e.,
the South Pole. We estimate the scintillation, the main noise source
in asteroseismology, at the pole by modeling the index of refraction
structure parameter from meterological data. The model results show that
at the Pole the variance of the relative intensity fluctuations--i.e.,
the scintillation--should be a factor of 5 smaller than at at Mauna
Kea. Taking into account the improvements possible with target selection
and instrumentation, the South Pole would be an excellent site for
asteroseismological work on Sun-like stars. (SECTION: Stars)
---------------------------------------------------------
Title: The Age of NGC 5927: Formation Timescales of the Halo and
Thick Disk
Authors: Fullton, L. K.; Carney, B. W.; Olszewski, E. W.; Zinn, R.;
Demarque, P.; Da Costa, G. S.; Janes, K. A.; Heasley, J. N.
1996ASPC...92..269F Altcode: 1996fogh.conf..269F
We present the HST WFPC2 VI<SUB>C</SUB> color-magnitude diagram (CMD) of
the metal-rich (thick) disk globular cluster NGC 5927. Our CMD indicates
that NGC 5927 is somewhat younger than other disk globular clusters with
known ages. Observations of the relative numbers of stars on the RGB and
RHB indicate a large helium abundance, Y = +0.29+/-0.04. Comparison of
the seven known thick disk globular clusters that have estimated ages
with ages of globulars that belong to the halo reveals a significant
overlap in age between the two cluster systems. As a group, the
disk clusters appear somewhat younger than their halo counterparts,
indicating that the Galactic halo began to form some 1--2 Gyr before
the thick disk, in agreement with studies by Carney et al. (1990)
and Marquez & Schuster (1994).
---------------------------------------------------------
Title: Photometry of Globular Cluster NGC 5466
Authors: Montgomery, Kent A.; Heasley, James N.; Janes, Kenneth A.
1994AAS...18510410M Altcode: 1994BAAS...26.1490M
We present photometry of the metal poor globular cluster NGC 5466 and
compare it with M92 a cluster of almost identical metallicity. The
photometry was obtained using the 3.6 meter Canada France Hawaii
telescope, the University of Hawaii 2.2 meter, and the Kitt Peak 0.9
meter. For both the UH and KPNO photometry we used a 2048x2048 CCD
allowing the the entire cluster to be imaged within a single frame. The
CFHT was equipped with a 1024x1024 CCD hence only a portion of the
cluster was imaged. The photometry from the 3 sets was combined to
produce a color-magnitude diagram which extends from the tip of the
red giant branch at a V magnitude of 13.5 to the main sequence 3.5
magnitudes below the turnoff at 23rd magnitude. NGC 5466 and M92 are
both essentially unreddened: the former has [Fe/H]=-2.22 and the latter
[Fe/H]=-2.24 (Zinn, 1985, ApJ, 293, 424). However, these two clusters
exhibit different horizontal branch types and thus can be used to probe
the hypothesis that age is the second parameter affecting horizontal
branch type. A direct comparison between the two cluster ridgelines is
used to determine the relative ages of the two clusters. In addition,
the distributions of stars both on the red giant and horizontal branches
is compared in order to investigate differences in cluster parameters
such as helium abundance.
---------------------------------------------------------
Title: Iterative/Recursive image deconvolution. Method and application
to HST images
Authors: Fullton, L. K.; Carney, B. W.; Coggins, J. M.; Janes, K. A.;
Heasley, J. N.; Seitzer, P.
1994ASPC...61..288F Altcode: 1994adass...3..288F
Image restoration results are presented using a new iterative/recursive
method for removing a linear, spatially-invariant blur from an
image. The new technique is a modification of the van Cittert iterative
deconvolution method. Iterative deconvolution begins by guessing what
the true image might be. If this guess is correct, then blurring it with
the point spread function (PSF) will produce the observed image. If
the guess is wrong, it can be corrected by the difference between the
observed image and the blurred guess. The iterative method is very
sensitive to noise in the image or error in the PSF, and convergence
is very slow. Our modifications improve the speed of convergence
and decrease noise sensitivity by using recursive restoration of
higher-order image derivatives to guide restoration of lower order
derivatives. The larger spatial extent of higher-order derivative
kernels regularizes the procedure by smoothing out small-scale
noise. Like the van Cittert iteration, the new iterative/recursive
algorithm is linear and flux-conserving. We have used the new algorithm
to restore both simulated Hubble Space Telescope (HST) images generated
with PSFs computed with the Tiny Tim software and HST Planetary Camera
images of the globular cluster NGC 6352. To account for the spatially
varying PSF of the HST images, we divided each image into subsections
over which the PSF is approximately constant and restored each section
separately using a PSF appropriate for the center of the section. The
simulations demonstrate that the intensity of point sources in the
restored images is conserved to within a factor of 1-2 percent over
a magnitude range of 6 dex. The color-magnitude diagram of NGC 6352
illustrates the level of photometric accuracy which can be obtained
from images deconvolved using our technique with the PSFs currently
available from the Space Telescope Science Institute. If better PSFs
become available, we believe the color-magnitude diagram could improve
significantly. For comparison, we have analyzed the unrestored images
with PSF-fitting photometry.
---------------------------------------------------------
Title: Stellar Photometry Software
Authors: Janes, Kenneth A.; Heasley, J. N.
1993PASP..105..527J Altcode:
We describe here the Stellar Photometry Software (SPS) that we have
developed at Boston University and the University of Hawaii. SPS
combines in a single program procedures for locating stars, computing
a mean stellar point-spread function (PSF), and performing aperture
and/or multiple PSF-fitting photometry, along with related bookkeeping
functions. The software can be run either interactively or in batch mode
on computers using the UNIX operating system. The performance of SPS
is compared to that of the photometry programs DoPHOT and IRAF/DAOPHOT
using both real and simulated CCD observations. A direct comparison
of the instrumental magnitudes shows that all three programs produce
comparable results. (SECTION: Instrumentation and Data Analysis)
---------------------------------------------------------
Title: Present and future implementation of high-speed networks at
4200 m: the Mauna Kea Observatories communications network
Authors: Sun, Tjet; Rhoads, Pui Hin H.; McLaren, Robert A.; Heasley,
James N.
1993SPIE.1784..116S Altcode:
The University of Hawaii Institute for Astronomy is developing
a high-bandwidth data communications system that will connect the
telescope facilities of the Mauna Kea Observatories with base support
facilities at lower elevation and with other institutions worldwide. A
key component of this project is an extensive fiber-optic cable plant
that links the observatories at the Mauna Kea summit with each other
and with a mid-level support facility. The first application of
the fiber-optic system, a fiber distributed data interface (FDDI)
token ring with a circumference of over 32 km and seven nodes,
is in operation. Plans are underway to install an OC-12 or OC-24
Sonet ring to improve the efficiency of fiber use. We describe the
needs and applications of the multinational Mauna Kea Observatories,
the current network configuration, impending network development,
and future networking plans to accommodate additional users and
applications. We summarize our experiences in dealing with FDDI token
rings over single-mode fibers.
---------------------------------------------------------
Title: NGC 6293 and NGC 6333: Photometry of Two Clusters in the
Central Bulge of the Galaxy
Authors: Janes, K. A.; Heasley, J. N.
1991AJ....101.2097J Altcode:
A preliminary investigation is conducted of two metal-poor globular
clusters, NGC 6293 and NGC 6333, which are projected against the
central bulge of the Galaxy. The observations consist of CCD B and V
images obtained on three nights when the seeing was between 0.6 and
0.8 arcsec. The clusters' color-magnitude diagrams, which reach just
to the main-sequence turnoff, show a morphology that confirms their
metal-poor nature; both clusters have well-defined giant branches and
blue horizontal branches, similar to those of M92. A comparison of NGC
6293 and NGC 6333 with the latter yields probable reddening values of
about 0.47 and 0.44 mag, and apparent distance moduli of about 16.0 and
15.8, respectively, placing the two clusters roughly 1-2 kpc from the
Galactic Center. The giant branch of NGC 6293 is deficient in bright
red giants, its tip being a full magnitude fainter than that of NGC
6333. This may be the consequence of the cluster having undergone
core collapse.
---------------------------------------------------------
Title: The M31 Globular Cluster G219: Resolved V and I CCD Photometry
Authors: Christian, Carol A.; Heasley, J. N.
1991AJ....101..848C Altcode:
We present VI CCD photometry of individual stars in the M31 globular
cluster G219 and the surrounding halo field. The color-magnitude
diagram for G219 shows that the cluster is at least as metal poor as
M15, consistent with the metallicity estimates from spectroscopy and
infrared photometry of its integrated light. The halo field appears to
be more metal rich than the cluster itself and shows an indication of
a clumping of stars that we interpret as the red end of the horizontal
branch. The mean metallicity of the halo field appears similar to
that of 47 Tuc, although a considerable range in metallicity is
present. Combined with information from related studies, this latter
result is consistent with the idea that the M31 halo field stars are
relatively metal rich and exhibit only a slight metallicity gradient
out to a significant galactocentric distance.
---------------------------------------------------------
Title: Photometry of the Outer Halo Globular Clusters NGC 5024 and
NGC 5053
Authors: Heasley, J. N.; Christian, Carol A.
1991AJ....101..967H Altcode:
New CCD photometry of the low-metallicity outer halo globular clusters
NGC 5024 and NGC 5053 is used to construct BV color-magnitude diagrams
that reach approximately 2 mag fainter than the turnoff in these
clusters. A differential comparison of the color-magnitude diagrams
with that of M92 indicates that all three clusters are identical in
age to within the uncertainties of the observations. With the addition
of these two clusters, color-magnitude diagrams are now available
for more than half of the globular clusters with Fe/H less than -2.0,
and with the exception of Ruprecht 106, no discernible spread in age
among these clusters is detected.
---------------------------------------------------------
Title: A Differential Comparison of 47 TUC and M71
Authors: Heasley, J. N.; Christian, C. A.
1991ASPC...13..266H Altcode: 1991fesc.book..266H
No abstract at ADS
---------------------------------------------------------
Title: Photometry of two metal-poor low-latitude globular clusters.
Authors: Janes, K. A.; Heasley, J. N.
1991ASPC...13..272J Altcode: 1991fesc.book..272J
The authors have undertaken a preliminary investigation of the
metal-poor low-latitude globular clusters NGC 6293 and NGC 6333 using
CCD images from the University of Hawaii 2.24-meter telescope, obtained
on two nights when the seeing was about 0.6″ The color-magnitude
(C-M) diagrams for the two clusters show well-defined giant branches
and blue horizontal branches and reach just to the main-sequence
turnoff. Their C-M diagram morphology resemble each other very closely
as well as that of M92; a comparison of NGC 6293 and NGC 6333 with the
latter yields probable reddening values of ≡0.47 and ≡0.44 mag
and apparent distance modulii of ≡16.0 and ≡15.8, respectively,
placing the clusters roughly 1 - 2 Kpc from the Galactic center.
---------------------------------------------------------
Title: Photometry of Stars in M 31 Globular Clusters
Authors: Christian, Carol A.; Heasley, James N.
1990ccd2.conf...65C Altcode: 1990ccd2.proc...65C
No abstract at ADS
---------------------------------------------------------
Title: The Parkes selected regions : deep optical and infrared
observations of radio galaxies and quasars at high redshifts.
Authors: Dunlop, J. S.; Peacock, J. A.; Savage, A.; Lilly, S. J.;
Heasley, J. N.; Simon, A. J. B.
1989MNRAS.238.1171D Altcode:
We report the results of an extensive optical and infrared study of the
178 radio sources in the Parkes Selected Regions (S > 100 mJy at
2.7 GHz). CCD observations have resulted in the essential completion
( >~95 per cent) of the optical identification programme, and have
provided B and R photometry of the new identifications. In addition, K
photometry has been completed for four of the six selected Regions. New
spectroscopic observations have increased the redshift content to 46
per cent, including virtually all the quasar candidates. We discuss
redshift estimation for the remaining radio galaxies in the light of the
B, R and K photometry; it appears unlikely that more than 10 objects
out of the total of 178 can lie at z > 2.5. We briefly discuss
some implications of the database presented here. The ability of this
sample to probe high-redshift space has resulted in some important
input on the high-redshift cut-off in the radio luminosity function,
as well as providing new information on the optical spectral evolution
of radio galaxies.
---------------------------------------------------------
Title: Erratum: "Photometry of Giant-Branch Stars in the M31 Globular
Cluster G1" [A. J. 96, 1312 (1988)]
Authors: Heasley, J. N.; Christian, Carol A.; Friel, Eileen D.; Janes,
K. A.
1989AJ.....97.1247H Altcode:
The caption to Fig. 1(a) on p. 1502 should read "I band cluster
candidate D1 from the list of Crampton et al. (1985). This object
appears to be a background elliptical galaxy." The caption to Fig. 1(b)
on p. 1503 should read "I band CCD frame of cluster G302."
---------------------------------------------------------
Title: Photometry of Giant Branch Stars in the M31 Globular Cluster G1
Authors: Heasley, J. N.; Christian, Carol A.; Friel, Eileen D.; Janes,
K. A.
1988AJ.....96.1312H Altcode:
We present the first deep two-color (V and I) CCD photometry of
individual stars in a M31 globular cluster. The color-magnitude diagram
for the stars in cluster G1 shows the brightest two magnitudes of a
well-defined giant branch. The position of the giant branch in color
indicates that G1 has a metallicity [Fe/H] ~ -0.7, consistent with
estimates from spectroscopy of its integrated light. The giant branch
of G1 falls roughly in the middle of the range occupied by the halo
field stars in M31. Thus, both the photometry and integrated-light
spectroscopy show that G1 appears to be near the mean metallicity of
the M31 halo population.
---------------------------------------------------------
Title: CCD Photometry of NGC 2419
Authors: Christian, C. A.; Heasley, J. N.
1988AJ.....95.1422C Altcode:
CCD photometry of NGC 2419 has been compared to similar data for other
metal-poor galactic globular clusters. Although NGC 2419 shares many
characteristics with other outer-halo clusters (large tidal and core
radius, low central surface brightness), the cluster is atypical of
that population in other respects. The object appears to be a close
analogy to metal-poor globulars located closer to the galactic center,
and in particular the comparison to M15 shows that the color-magnitude
diagrams of the two clusters are very similar. The two clusters are
very similar in age and metallicity. The predominant difference between
M15 and NGC 2419 is that the number of RR Lyraes is significantly
smaller in the latter cluster, as well as a lack of an extreme blue
tail to the horizontal branch. The observed distance modulus to NGC
2419 appears to be (m-M)<SUB>V</SUB> = 20.0±0.15, with a reddening
E(B-V) = 0.11±0.05. Comparison to theoretical isochrones suggest the
age of the cluster is 16 Gyr and supports the distance modulus found
empirically. Oxygen-rich models (Fahlman, Richer, and VanderBerg 1985)
and the new Yale models (Green, Demarque, and King 1987) were also
examined.
---------------------------------------------------------
Title: IRAS Galaxy Redshifts
Authors: Hill, G. J.; Heasley, J. N.; Becklin, E. E.; Wynn-Williams,
C. G.
1988AJ.....95.1031H Altcode:
IRAS GALAXY REDSHIFTS Redshifts and brief spectral information
are presented for 90 IRAS galaxies. A subsample selected from IRAS
circulars 11 and 16 to have high 25 micron to 60 micron flux-density
ratio includes many Seyfert galaxies, two of which show broad lines.
---------------------------------------------------------
Title: NGC 2298- Another Perfectly Normal Globular Cluster in the
Outer Halo
Authors: Janes, Kenneth A.; Heasley, J. N.
1988AJ.....95..762J Altcode:
New CCD photometry of the halo globular cluster NGC 2298 is used
to construct BV and VR color-magnitude diagrams. Photoelectric UBV
photometry of stars in the cluster region indicates a reddening value
of the order of 0.20, and a comparison of the cluster with five other
clusters of similar metallicity (M68, NGC 5024, NGC 5053, M92, and M15)
leads to values of E(B-V) = 0.18 and (m-M)<SUB>V</SUB> = 15.45. The
color-magnitude diagrams of NGC 2298 and the five comparison clusters
are virtually identical; when their main sequences are matched, the
giant and horizontal-branch regions are aligned within the (small)
photometric uncertainties. However, using the derived value for the
reddening to NGC 2298, the cluster cannot be matched to published
theoretical isochrones without an additional color shift.
---------------------------------------------------------
Title: The PC as a Scientific Image Processing Workstation
Authors: Jacoby, George H.; Heasley, J. N.
1988PASP..100..137J Altcode:
We describe two computer hardware and software systems based on personal
computers which are used for specific image processing tasks in a local
compute mode and also as workstations linked to larger computers. The
advantages of the PC approach include low cost, continuous availability
of a single user computer, and excellent interactive response. Some
of the current disadvantages are the need to write some software,
limited compute speed, and limited available memory, all of which are
expected to be alleviated with products recently released.
---------------------------------------------------------
Title: Cluster Photometry Programs at the University of Hawaii
Authors: Heasley, J. N.
1988csa..proc....3H Altcode: 1988LDP....10....3H
This presentation reviews completed and ongoing work at the University
of Hawaii, and includes the following topics: (1) General calibration
of globular cluster photometry. (2) Photometry of extremely metal-poor
globular clusters. (3) General cluster photometry. (4) CCD photometry
of the most distant globular clusters in the Milky Way. (5) New
observations from the CFHT have for the first time resolved a globular
cluster in a spiral galaxy in the Local Group into individual stars. The
photometry of these CCD images has produced the first CM diagram for
the giant-branch stars in a spiral galaxy other than the Milky Way. The
properties of the cluster inferred from the CM diagram are compared
to what has been known previously about the cluster from studies of
its integrated light.
---------------------------------------------------------
Title: Radio and Optical Studies of a Complete Sample of IRAS Galaxies
Authors: Wolstencroft, R. D.; Unger, S. W.; Pedlar, A.; Heasley,
J. N.; Parker, Q. A.; Menzies, J. W.; Savage, A.; MacGillivray, H. T.;
Legget, S. K.; Gang, W.; Clowes, R. G.
1988LNP...297..202W Altcode: 1988ctc..conf..202W
Radio maps, spectra and CCD images have been obtained for almost all the
158 objects in a complete sample of IRAS galaxies. The linear relation
between radio and far-infrared luminosity is valid over the complete
luminosity range (up to L<SUB>IR</SUB> = 1.8×10<SUP>12</SUP>L_sun;,
H_sun; = 75 km s<SUP>-1</SUP>Mpc<SUP>-1</SUP>). The majority of the
10 most luminous galaxies show evidence of tidal disruption and have
companion galaxies at projected separations which range between 6 and
138 kpc. The second most luminous galaxy, IRAS 00275-2859, is a quasar
with a spectrum reminiscent of a broad line absorption quasar.
---------------------------------------------------------
Title: CCD photometry of the globular cluster NGC 4147.
Authors: Friel, Eileen D.; Heasley, J. N.; Christian, Carol A.
1987PASP...99.1248F Altcode:
The authors present results of CCD photometry in B and V for the
globular cluster NGC 4147. The color-magnitude diagram reaches
fainter than V = 22, some 3 magnitudes below the main-sequence
turnoff. The morphology of the C-M diagram resembles that of a cluster
of intermediate metallicity with a normal blue horizontal branch. Rough
estimates of the integrated light from additional CCD data in B and
I suggest, however, that the population revealed in the C-M diagram
from the outer regions may not be representative of the population in
the central regions of the cluster. Determination of the age of the
cluster from fitting theoretical isochrones is difficult because of
uncertainties in the distance modulus of the cluster. An age of 17 Gyr
is implied. The revised Yale isochrones indicate an age of some 2 Gyr
younger. If models with enhanced oxygen abundances are used, the ages
deduced would also be 2 - 3 Gyr younger. Although determinations of
the absolute age of NGC 4147 require knowledge of the absolute distance
scale and choice of theoretical models, these alternative age estimates
are consistent with those made for other clusters using the same models.
---------------------------------------------------------
Title: CCD Photometry of the Globular Cluster NGC 288
Authors: Pound, Marc W.; Janes, Kenneth A.; Heasley, J. N.
1987AJ.....94.1185P Altcode:
Observations obtained in 1983 with a CCD at the University of Hawaii
2.2-m Mauna Kea telescope are used to produce a BV color-magnitude
diagram for main-sequence stars in NGC 288. Results indicate an Fe/H
abundance ratio of -1.30 + or - 0.10 dex. If NGC 288 has a reddening
of E(B-V) = 0.03, a true distance modulus of 14.46 + or - 0.2 is
obtained. It is found from a comparison of the present color-magnitude
diagram to theoretical isochrones that the data are not in agreement
with the models for the assumed parameters. Abundance variations other
than the Fe/H abundance ratio may explain the discrepancy between the
main-sequence turnoff of NCD 288 and that of NGC 362.
---------------------------------------------------------
Title: Activity in early F-type stars in the Hyades.
Authors: Wolff, Sidney C.; Heasley, James N.
1987PASP...99..957W Altcode:
Observations of the equivalent width of D3 He I A 5876 in 14
main-sequence stars in the Hyades show that stellar activity in these
stars is closely similar to that seen in early F-type field stars. The
onset of activity occurs at about (B - V) = 0.30 m, and the activity
level in stars bluer than (B - V) = 0.45 m does not correlate with
rotation. There is no evidence of a decline of activity with increasing
age during the rather narrow time interval spanned by the main-sequence
lifetimes of early F-type stars. The sharp minimum in lithium abundance
that is seen in Hyades stars of middle F spectral type occurs at about
the color that marks the boundary between temperature regimes where
activity does and does not correlate with rotation.
---------------------------------------------------------
Title: The Properties of Highly Luminous IRAS Galaxies
Authors: Wolstencroft, R. D.; Puxley, P. J.; Heasley, J. N.; Leggett,
S. K.; Savage, A.; MacGillivray, H. T.; Clowes, R. G.
1987NASCP2466..623W Altcode: 1987sfig.conf..623W
From a complete sample of 154 galaxies identified with IRAS sources
in a 304 sq deg area centered on the South Galactic Pole, a subsample
of 58 galaxies with L<SUB>IR/L</SUB> sub B > 3 was chosen. Low
resolution spectra were obtained for 30% of the subsample and redshifts
and relative emission line intensities were derived. As a class these
galaxies are very luminous with < L<SUB>IR</SUB> > = 2.9 x 10 to
the 11th power L<SUB>0</SUB> and (L<SUB>IR)</SUB> max = 1.3 x 10 to the
12th power L<SUB>0.</SUB> CCD images and JHK photometry were obtained
for many of the subsample. The galaxies are for the most part newly
identified and are optically faint, with a majority showing evidence
of a recent interaction. Radio continuum observations of all galaxies
of the subsample were recently obtained at 20 cm VLA with about 75%
being detected in a typical integration time of about 10 minutes.
---------------------------------------------------------
Title: CCD Photometry of the Globular Cluster NGC 4147
Authors: Friel, E. D.; Heasley, J. N.; Christian, C. A.
1987BAAS...19..642F Altcode:
No abstract at ADS
---------------------------------------------------------
Title: CCD photometry of the outer halo clusters Pal 4 and NGC 2419.
Authors: Christian, C. A.; Heasley, J. N.
1987ESOC...27..381C Altcode: 1987sedo.work..381C
CCD photometry of two outer halo globular clusters, Pal 4 and NGC
2419, has been obtained to sample the stellar population to V =
25 mag. The color-magnitude diagram of Pal 4, when compared to both
other globular clusters and theoretical isochrones suggest that this
object is a moderately metal poor cluster with [Fe/H] ≡ -1.7 with
(m-M)<SUB>0</SUB> = 20.1, and E(B-V) = 0.02 mag. The age of the
cluster appears to be ≡15 Gyr, but the cluster does exhibit the
red horizontal branch and distinct asymptotic giant branch typical of
"second parameter" clusters. Alternatively NGC 2419 appears to be a
close analog to M15, with (m-M)<SUB>0</SUB> = 20.0, and E(B-V) = 0.12.
---------------------------------------------------------
Title: Radio and optical studies of high luminosity IRAS galaxies.
Authors: Wolstencroft, R. D.; Unger, S. W.; Pedlar, A.; Heasley,
J. N.; Parker, Q. A.; Menzies, J. W.; Savage, A.; MacGillivray, H. T.;
Leggett, S. K.; Clowes, R. G.
1987sbge.proc..269W Altcode: 1987scge.proc..269W
Follow-up observations of a complete sample of 154 IRAS galaxies,
optically identified down to B = 21, indicate that between
3 and 9% of the sample are ultraluminous (L<SUB>IR</SUB> >
10<SUP>12</SUP>L_sun;) depending on the choice of H<SUB>0</SUB> (75 to
50 km s<SUP>-1</SUP>Mpc<SUP>-1</SUP>). VLA observations at 20 cm of the
complete sample indicate that 85% are detected above 1 mJy and for the
most part the radio emission is centrally concentrated. The tight linear
relation between radio and infrared luminosities is valid at the highest
luminosities. Of the 11 most luminous objects one is a quasar: it fits
the radio infrared relation very well which suggests that the infrared
and radio emission has the same origin as in the other IRAS galaxies,
i.e. it probably originates primarily in regions of star formation in
the host galaxy. The other 10 very luminous galaxies are either close
but resolved mergers or double galaxies, presumably interacting.
---------------------------------------------------------
Title: The Main-Sequence Color-Magnitude Diagram of M92
Authors: Heasley, J. N.; Christian, C. A.
1986ApJ...307..738H Altcode:
A new color-magnitude (C-M) diagram for main-sequence stars in the
globular cluster M 92 is presented. The observations upon which
this diagram is based were obtained with an RCA CCD at the 3.6 m
Canada-France-Hawaii telescope. These new data refine the position
of the cluster ridge lines in the lower main sequence, the subgiant
branch, and the lower giant branch. A comparison of the new C-M
diagram with new theoretical isochrones shows that the shapes of
the models are in good agreement with the observations, but a large
shift in color is required to bring the theory and observations into
agreement. Possible explanations for this discrepancy are discussed. The
new M 92 observations and recent work on M13, M15, and 47 Tuc combined
with the new isochromes show that the globular cluster distance scale
developed by Sandage from the RR Lyrae period-luminosity-amplitude
relation is consistent for the relative distances if all the clusters
are the same age.
---------------------------------------------------------
Title: The Open Cluster NGC 2158: Erratum
Authors: Christian, Carol A.; Heasley, J. N.; Janes, Kenneth A.
1986ApJ...305..954C Altcode:
No abstract at ADS
---------------------------------------------------------
Title: IRAS 04238+5336: A Young Reflection Nebula Surrounding a
Double Star
Authors: Wynn-Williams, C. G.; Heasley, J. N.; Depoy, D. L.; Hill,
G. J.; Becklin, E. E.
1986ApJ...304..409W Altcode:
IRAS 04238 + 5336P03 is identified with a 17th-magnitude compact
nebulous object which contains a 1.6-arcsec double star. About 99
percent of the 450 solar luminosities luminosity of the source is
radiated longward of 1 micron. The source displays an A-type visible
spectrum, strong molecular hydrogen emission lines at 2.4 microns,
and a dust emission feature at 3.3 microns. It lies within a small
molecular cloud. The object is one of the first clear examples of a
binary system young enough to be still interacting with the interstellar
cloud out of which it formed. The infrared source is highly extended
at 10 microns (about six arcsecs); it is one of the few examples of a
10 microns source that shows extended emission without a distributed
heating mechanism. The results are explained by a population of very
small particles that are temporarily heated to high temperatures.
---------------------------------------------------------
Title: CCD and photographic photometry of NGC 1904.
Authors: Heasley, J. N.; Janes, K. A.; Christian, C. A.
1986AJ.....91.1108H Altcode:
Combined CCD and photographic photometry of the globular cluster NGC
1904 are presented. The data reduction procedures for the CCD and
digital iris photometry are presented. The cluster's C-M diagram is
nearly identical in morphology to that of the nearby globular cluster
M13, the only significant difference being the subgiant branch, where
the NGC 1904 ridge line is flatter than in M13. If a cluster age of
16 Gyr, as suggested by theoretical models, is adopted, the turnoff
and main-sequence region in the C-M diagram are fit by VandenBerg's
(1983) isochrone for Y = 0.20 and Z = 0.001 for a distance modulus of
15.65 and a reddening of 0.01. If the cluster is more metal-poor, as
suggested by Zinn and West (1984), then an older isochrone is required
to match the observations.
---------------------------------------------------------
Title: High-resolution imaging from Mauna Kea: the triple quasar in
0.3-arc s seeing
Authors: Henry, J. P.; Heasley, J. N.
1986Natur.321..139H Altcode: 1986Nat...321..139H
The `triple' quasar, PG1115 +08 (which actually contains at least
four objects: A<SUB>1</SUB>, A<SUB>2</SUB>, B and C) was the second
gravitational lens object to be found<SUP>1</SUP>. But because of its
small angular scale (<2.5 arc s separation between components)
and lack of detectable radio emission, which precludes the use of
high-resolution interferometric radio techniques, not much is known
about this object. In particular, the lensing object(s) have not been
identified. Here we report imaging observations made on a night of
exceptional seeing, as well as spectroscopy of two galaxies near
the quasar. We find that there is a galaxy centred approximately
midway between the two A components. The properties of this galaxy
are consistent with it being the brightest member of a small group at
a group redshift of 0.305. Although detailed modelling is required,
it is likely that the galaxy and its group are the lenses.
---------------------------------------------------------
Title: Color-Magnitude Diagram of Palomar 4: CCD Photometry
Authors: Christian, C. A.; Heasley, J. N.
1986ApJ...303..216C Altcode:
Photometry of the globular cluster Pal 4 was obtained with the RCA CCD
camera on the 3.6 m Canada-France-Hawaii Telescope on Mauna Kea. The
color-magnitude diagram of the cluster shows a well-defined red
horizontal branch, typical of outer halo systems, and an asymptotic
giant branch well separated from the giant branch. The population of
Pal 4 has been sampled to the main-sequence turnoff region (V = 25),
allowing a detailed comparison of this distant object with theoretical
models. The cluster parameters consistent with the CCD data are (m
- M)0 = 20.1 + or - 0.1 mag, E(B - V) = 0.02 + or - 0.02, and Fe/H
forbidden line = -1.7 + or - 0.1 with Y =0.2. The age of the cluster,
determined by comparison with the isochrones of VandenBerg and Bell
(1985) is consistent with an age of 15 + or - 1 Gyr, similar to inner
halo globular clusters with ages determined in the same way.
---------------------------------------------------------
Title: The distribution of dust in the inner coma of comet
IRAS-Araki-Alcock (1983d)
Authors: Storrs, A. D.; Tokunaga, A. T.; Christian, C. A.; Heasley,
J. N.
1986Icar...66..143S Altcode:
High-resolution images of comet IRAS-Araki-Alcock taken on five separate
through its closest approach to the Earth are presented. The images
were taken in the red and near-infrared, and so consist primarily of
continuum scattering from dust grains. The distribution of dust in the
inner coma varied widely from day to day, although the dust was emitted
primarily in the sunward direction on all days. The main emission
exhibited a lag angle consistent with a nuclear rotational vector that
was oriented approximately along the line of sight on May 11.3 1983
UT. A curved filament, extending in the sunward direction, was seen
in the deepest images obtained on this day as well, and the azimuthal
distribution of dust was strongly of dust was strongly peakeed in the
sunward direction. The presence of the curved filament is indicative of
dust outflow from an active region, on a mantled nucleus. On all days,
the brightness falls off slower than the r<SUP>-</SUP> expected for
uniform outflow, which is interpreted as resulting from fragmentation
of the dust grains as they traveled through the coma. The nuclear
region appeared stellar on all days. The seeing-limited spatial
resolutions was 19 km on May 11.3, but deconvolution of the images
with the instrumental profile enables an upper limit of 17 km to be
placed on the diameter of the nucleus.
---------------------------------------------------------
Title: Deep(EST) colour-magnitude diagrams of clusters
Authors: Christian, C. A.; Heasley, J. N.
1986Ap&SS.118..453C Altcode:
Color-magnitude diagrams are presented for the open cluster NGC 2158
and globular clusters Pal4 and NGC 1904.
---------------------------------------------------------
Title: The Open Cluster NGC 2158
Authors: Christian, C. A.; Heasley, J. N.; Janes, K. A.
1985ApJ...299..683C Altcode:
CCD photometry on the BV system is presented for the intermediate-age
open cluster NGC 2158. A new color-magnitude diagram for the cluster is
derived which extends well down onto the main sequence. Using estimates
for the cluster metallicity and reddening from the literature and new
values derived from low-resolution IIDS spectra of several cluster
giants, an age is obtained for NGC 2158 of 3.0 + or - 1.0 Gyr and an
apparent distance modulus of 14.4. In comparison to NGC 2420, an open
cluster also located in the anticenter but further from the Galactic
plane, NGC 2158 is slightly younger and more metal-poor. The globular
cluster 47 Tucanae and NGC 2420 have been thought to have the same
metallicity, a conclusion that has led to considerable discussion of the
differences in the color-magnitude diagrams of these two clusters. In
contrast, evidence is found that NGC 2158 and 47 Tuc are more similar
in metallicity. NGC 2158 is also similar in age and composition to the
type VI clusters seen in the Large Magellanic Cloud. A comparison of
NGC 2158 with NGC 1978 in the LMC leads to a distance modulus of 18.2
for the LMC.
---------------------------------------------------------
Title: He I lambda 5876 as an indicator of activity in main-sequence
stars.
Authors: Wolff, S. C.; Heasley, J. N.; Varsik, J.
1985PASP...97..707W Altcode:
The absorption line He I λ5876 (D<SUB>3</SUB>) is observed in many
main-sequence stars with spectral types as early as F0 and as late
as K5. The equivalent width of D<SUB>3</SUB> correlates well with
the strength of the emission in Ca II H and K and with X-ray flux for
late F-, G-, and K-type stars. In early F-type stars the strength of
D<SUB>3</SUB> shows no apparent correlation with rotational velocity,
while a correlation does appear to be present in late F-type stars. This
result is compatible with other data that suggest that stars with
shallow convection zones differ significantly in terms of the nature of
stellar activity from stars of later type with deeper convective zone.
---------------------------------------------------------
Title: The IRAS galaxy 0421+040P06 : an active spiral (?) galaxy
with extended radio lobes.
Authors: Beichman, C.; Wynn-Williams, C. G.; Lonsdale, C. J.; Persson,
S. E.; Heasley, J. N.; Miley, G. K.; Soifer, B. T.; Neugebauer, G.;
Becklin, E. E.; Houck, J. R.
1985ApJ...293..148B Altcode:
The infrared bright galaxy 0421 + 040P06 detected by IRAS at 25 and
60 microns was studied at optical, infrared, and radio wavelength. It
is a luminous galaxy with apparent spiral structure emitting 4 x 10
to the 37th power from far-infrared to optical wavelengths. Optical
spectroscopy reveals a Seyfert 2 emission line spectrum, making 0421
+ 040P06 the first active galaxy selected from an unbiased infrared
survey of galaxies. The fact that this galaxy shows a flatter energy
distribution with more 25 micron emission than other galaxies in the
infrared sample may be related to the presence of an intense active
nucleus. The radio observations reveal the presence of a non-thermal
source that, at 6 cm, shows a prominent double lobed structure 20 to 30
kpc in size extending beyond the optical confines of the galaxy. The
radio source is three to ten times larger than structures previously
seen in spiral galaxies.
---------------------------------------------------------
Title: The determination of the helium abundance in main-sequence
B stars.
Authors: Wolff, S. C.; Heasley, J. N.
1985ApJ...292..589W Altcode:
It is pointed out that the abundances of deuterium, helium, and lithium
provide fundamental constraints on cosmological models. The central
question is related to the compatibility of the observed abundances with
big bang models of primordial nucleosynthesis, taking into account a
modification by subsequent nuclear processing in stars or a modification
of standard models. The present paper has the objective to assess
critically the feasibility of deriving accurate helium abundances
from measurements of the photospheric lines in main-sequence B-type
stars. A method is established for assigning atmospheric parameters to
main-sequence stars with spectral types in the range (approximately)
B1-B5. It is found that an analysis of stars in distant anticenter H II
regions and clusters offer an alternative method which seems capable of
determining relative abundances with more than the requisite accuracy.
---------------------------------------------------------
Title: He I λ5876 as a Chromospheric Activity Indicator
Authors: Varsik, J. R.; Wolff, S. C.; Heasley, J. N.
1984BAAS...16..940V Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The IRAS Galaxy 0421+040P06: An Active Spiral Galaxy with
Extended Radio Lobes
Authors: Wynn-Williams, C. G.; Beichman, C.; Lonsdale, C. J.; Persson,
S. E.; Heasley, J. N.; Miley, G. K.; Soifer, B. T.; Neugebauer, G. E.;
Begklin, E. E.; Houck, J. R.
1984BAAS...16..916W Altcode:
No abstract at ADS
---------------------------------------------------------
Title: IRAS 0423+536P03: A Remarkable Galactic Infrared Source
Authors: Becklin, E. E.; Heasley, J. N.; Depoy, D. L.; Hill, G. J.;
Wynn-Williams, C. G.
1984BAAS...16Q.976B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Numerical Restoration of Astronomical Images
Authors: Heasley, J. N.
1984PASP...96..767H Altcode:
The two iterative deconvolution algorithms are examined in the context
of restoring optical images for the effects of seeing. Both algorithms
are easy to program, computationally efficient, and are well suited
to image restoration applications even on minicomputers. Examples
are presented showing restorations of computer simulated images,
CCD observations of Uranus and Neptune, and of the M87 jet. Both
procedures are found to give resolution improvements in the restored
image comparable to that obtained by the Maximum Entropy Method.
---------------------------------------------------------
Title: The IRAS galaxy 0421+040P06: an active spiral (?) galaxy with
extended radio lobes
Authors: Beichman, C. A.; Wynn-Williams, C. G.; Lonsdale, C. J.;
Persson, S. E.; Heasley, J. N.; Miley, G. K.; Soifer, B. T.;
Neugebauer, G.; Becklin, E. E.; Houck, J. R.
1984STIN...8515536B Altcode:
The infrared bright galaxy 0421+040P06 detected by IRAS at 25 and 60
microns was studied at optical, infrared, and radio wavelength. It
is a luminous galaxy with apparent spiral structure emitting 4 x 10
to the 37th power from far-infrared to optical wavelengths. Optical
spectroscopy reveals a Seyfert 2 emission line spectrum, making
0421+040P06 the first active galaxy selected from an unbiased infrared
survey of galaxies. The fact that this galaxy shows a flatter energy
distribution with more 25 micron emission than other galaxies in the
infrared sample may be related to the presence of an intense active
nucleus. The radio observations reveal the presence of a non-thermal
source that, at 6 cm, shows a prominent double lobed structure 20 to 30
kpc in size extending beyond the optical confines of the galaxy. The
radio source is three to ten times larger than structures previously
seen in spiral galaxies.
---------------------------------------------------------
Title: The He I D3 line in G and K stars.
Authors: Wolff, S. C.; Heasley, J. N.
1984PASP...96..231W Altcode:
High-resolution spectra have been obtained of 18 late-type stars
in order to search for He I λ5876. This feature is present in
main-sequence stars that are known to have active chromospheres, and
the line widths, depths, and the ratio λ10830/λ5876 in integrated
starlight are similar to what is measured in solar plages. The line
λ5876 is also present, with an equivalent width of 35 mÅ, in the
RS CVn star λ And. In the remaining giants and supergiants in the
present sample, the ratio λ10830/λ5876 is apparently much larger
than it is in either solar plages or active dwarfs, and the conditions
under which the helium triplet lines are formed may be very different
in highly luminous stars. Theoretical analyses of the line-formation
process indicate coronal emission may not be the dominant factor in
determining the helium level populations in main-sequence stars.
---------------------------------------------------------
Title: Restored methane band images of Uranus and Neptune
Authors: Heasley, J. N.; Pilcher, C. B.; Howell, R. R.; Caldwell, J. J.
1984Icar...57..432H Altcode:
Charge-coupled device images of Uranus and Neptune taken in the 8900-Å
absorption band of methane are presented. The images have been digitally
processed by means of nonlinear deconvolution techniques to partially
remove the effects of atmospheric seeing. The restored Uranus images
show strong limb brightening consistent with previous observations and
theoretical models of the planet's atmosphere. The computer-processed
images of Neptune show discreted cloud features similar to those
reported previously by B. A. Smith, H. J. Reitsema and S. M. Larson
(1979 Bull. Amer. Astron. Soc.11, 570). A time series of the restored
Neptune images shows a continuous variation which may be due to the
planet's rotation.
---------------------------------------------------------
Title: The nature of stellar active regions.
Authors: Wolff, S. C.; Heasley, J. N.; Timothy, J. G.
1983PASP...95.1025W Altcode:
Observational estimates of chromospheric radiative loss rates in Ca
II H and K in main-sequence F, G, and K dwarfs are used to compare
stars that span a range of activity levels with each other and with
the sun. For stars with spectral types similar to that of the sun,
it is found that chromospheric radiative losses in stars with active
chromospheres exceed the flux emitted by plages on the sun at solar
maximum by about a factor of 6. If this difference is due primarily
to a difference in the fraction of the stellar surface covered by
plage-like material, and not to a change in the character of the
emission-line regions, then more than half of the stellar surface in
stars with large chromospheric radiative loss rates must be covered
by active regions. It is also possible to show that active regions in
young solar-type stars extend at least to latitudes + or - 25 deg from
the rotational equator and that a typical individual region contributes
no more than 2 percent - 3 percent of the total H and K emission. In
Kappa Cet, observations show that the rotational modulation persisted
in both phase and amplitude for at least 100 days (12 rotation cycles).
---------------------------------------------------------
Title: Multiwavelength CCD Observations of IRAS Source Fields
Authors: Becklin, E. E.; Depoy, D. L.; Heasley, J. N.; Wynn-Williams,
C. G.
1983BAAS...15Q.934B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Ground-Based Studies of IRAS Sources
Authors: Becklin, E. E.; Depoy, D. L.; Heasley, J. N.; Lester, D. F.;
Wynn-Williams, C. G.
1983BAAS...15Q.914B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The modelling of the solar upper photosphere and lower
chromosphere based upon ATM data
Authors: Heasley, J. N.
1983huha.rept.....H Altcode:
Spectral data obtained by the SO82B experiment aboard SKYLAB were used
to critically evaluate existing models of the solar upper photosphere
and lower chromosphere. These spectral diagnostics were used to develop
new solar models.
---------------------------------------------------------
Title: Hα line profiles in B stars : comparison of theory and
observations.
Authors: Heasley, J. N.; Wolff, S. C.
1983ApJ...269..634H Altcode:
Observations of H-alpha in 17 main-sequence stars of spectral types
B0-B5 have been compared with the profiles calculated from model
atmospheres. Statistical equilibrium models by Mihalas (1970) provide
an excellent fit to the core of H-alpha, but the LTE line-blanketed
models by Kurucz (1979) provide a slightly better representation of
the line wings. If Stromgren photometry is available, so that T(eff)
can be derived from the c(0) index, then log g can be derived with an
accuracy of + or - 0.15.
---------------------------------------------------------
Title: Structure and spectrum of quiencent prominences. IV. The
ultraviolet ionization continua of hydroden and helium.
Authors: Heasley, J. N.; Milkey, R. W.
1983ApJ...268..398H Altcode:
The formation of the ground-state ionization continua of hydrogen
and neutral helium in quiescent prominences has been investigated
by using isothermal and isobaric slab models. The hydrogen and helium
ionization equilibria are dominated by the extreme ultraviolet radiation
field incident on the prominence. The Lyman continuum brightness is
dependent only on the incident radiation and the optical thickness of
the prominence. The ratio of the intensity in the He I to the Lyman
continuum is principally a function of the hardness of the incident
radiation and the helium abundance and is only secondarily a function
of the optical thickness of the slab and the gas pressure. The color
temperatures of the continua, when corrected for optical depth effects,
are good indicators of the electron temperature in the prominence. The
slab models used in this study, which were developed to reproduce the
visible spectrum hydrogen and helium lines, are in reasonable agreement
with existing ultraviolet observations.
---------------------------------------------------------
Title: He I lines in B stars : comparison of non-local thermodynamic
equilibrium models with observations.
Authors: Heasley, J. N.; Wolff, S. C.; Timothy, J. G.
1982ApJ...262..663H Altcode:
Profiles of He gamma-gamma 4026, 4387, 4471, 4713, 5876, and 6678
have been obtained in 17 stars of spectral type B0-B5. Parameters
of the nonlocal thermodynamic equilibrium models appropriate to each
star are determined from the Stromgren index and fits to H-alpha line
profiles. These parameters yield generally good fits to the observed
He I line profiles, with the best fits being found for the blue He
I lines where departures from local thermodynamic equilibrium are
relatively small. For the two red lines it is found that, in the
early B stars and in stars with log g less than 3.5, both lines are
systematically stronger than predicted by the nonlocal thermodynamic
equilibrium models.
---------------------------------------------------------
Title: The modeling of the solar upper photosphere and lower
chromosphere based upon ATM data
Authors: Heasley, J. N.
1982STIN...8312033H Altcode:
The use of the solar H I Lyman spectral line as a diagnostic of the
lower to middle chromosphere is discussed. Quiet sun Lyman profiles
from the photographic spectra were subjected to data reduction and
appropriate theoretical modelling was accomplished. Apollo telescope
mount data was utilized.
---------------------------------------------------------
Title: CCD Images of Uranus and Neptune.
Authors: Pilcher, C. B.; Howell, R. R.; Heasley, J. N.
1982BAAS...14Q.761P Altcode:
No abstract at ADS
---------------------------------------------------------
Title: CCD Images of Uranus and Neptune.
Authors: Pilcher, C. B.; Howell, R. R.; Heasley, J. N.
1982BAAS...14R.761P Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The aluminum I autoionization doublet in the quiet solar
spectrum
Authors: Heasley, J. N.; Roussel-Dupre, D.; McAllister, H. C.;
Beerman, C.
1981ApJ...248..352H Altcode:
Observations are presented of the Al I autoionization doublet 1932
A and 1936 A in the quiet solar spectrum, obtained from the NRL
slit spectrograph aboard Skylab and from the University of Hawaii
Echelle Rocket Spectrograph. The observed profiles are compared with
theoretical spectra computed for the Harvard Smithsonian Reference
Atmosphere and the Vernazza, Avrett and Loeser (1976) solar models. It
is found that nonlocal thermodynamic equilibrium effects are important
in the line-formation problem and the synthetic spectra are in good
agreeement with the data.
---------------------------------------------------------
Title: Far-infrared continuum observations of solar faculae
Authors: Lindsey, C.; Heasley, J. N.
1981ApJ...247..348L Altcode:
New observations of photospheric faculae in the far-infrared (10-25
micron wavelength) continuum are presented. Two-beam linear scans with
10 arcsec and 20 arcsec resolution were used to compile statistics
on infrared continuum emission from faculae surrounding sunspots. The
infrared facular excess above the quiet sun continuum is found to be
much smaller than that predicted by plane parallel photospheric models
constructed from Mg II h and k line wing observations. It is proposed
that the discrepancy results from unresolved granular structure in
which the facular granules occupy only about 0.1 of the resolved
surface area in the low photosphere.
---------------------------------------------------------
Title: Hei Lambda 4922 IN B-Stars - Comparison of Theory and
Observations
Authors: Heasley, J. N.; Wolff, S. C.
1981ApJ...245..977H Altcode:
Profiles of the He I λ4922 line have been observed in 15 B-type stars
with an unintensified Reticon detector on the coudé spectrograph of the
University of Hawaii's 2.2 m telescope on Mauna Kea. The observations
are compared with the theoretical line profiles computed by Mihalas,
Barnard, Cooper, and Smith, who used an improved line broadening
theory. The results show that the computed profiles reproduce the core
and red wing of the stellar profiles, but the forbidden component in
the blue wing of the line is deeper and broader than the theoretical
predictions. Photographic Hα line profiles have been obtained for three
of our program stars, and for this sample we find that the Balmer line,
He I λ4922, and Strömgren photometric colors yield a consistent set
of atmospheric parameters.
---------------------------------------------------------
Title: Analysis of the solar magnesium lines
Authors: Heasley, J. N.; Allen, M. S.
1980ApJ...237..255H Altcode:
The observed quiet-sun profiles for a number of Mg I and II lines are
compared with theoretical spectra computed for two upper-photosphere
lower-chromosphere models published by Ayres and Linsky (1976). Both the
Mg I and the Mg II resonance line wings, observed with the University
of Hawaii Echelle Rocket Spectrographs, favor a model with a higher
temperature in the upper photosphere than required to match the visible
region lines 4571 and 5172. Neither model atmosphere reproduces the
observed shapes in the cores of the strong lines or the limb darkening
of the 4571 A intercombination line. The wings of the ultraviolet
lines in plages can be reproduced either with a mean one-component
atmosphere or by a two-component model with an ad hoc filling factor.
---------------------------------------------------------
Title: Far Infrared Continuum Observations of Solar Faculae
Authors: Lindsey, C. A.; Heasley, J. N.
1980BAAS...12..437L Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Multidimensional radiative transfer in stratified atmospheres:
gray radiative equilibrium.
Authors: Kneer, F.; Heasley, J. N.
1979A&A....79...14K Altcode:
This paper tests the validity of the multidimensional Eddington,
or diffusion, approximation in radiative transfer in a gray
radiative-equilibrium atmosphere with opacity increasing exponentially
toward the stellar interior. The diffusion approximation is unacceptable
at small optical depths. The height dependence of intensity fluctuations
is studied systematically by adopting the above simplified model
atmosphere for the solar photosphere. Lateral radiative exchange is
efficient and drastically damps the fluctuations in the uppermost
layers.
---------------------------------------------------------
Title: Discussion
Authors: Acton, L. W.; Engvold, O.; Heasley, J. N.; Heyvaerts, J.;
Hirayama, T.; Kundu, M. R.; Leroy, J. L.; Malville, J.; Rust, D. M.;
Zirin, H.
1979phsp.coll...31A Altcode: 1979IAUCo..44...31A
No abstract at ADS
---------------------------------------------------------
Title: Frequency Redistribution Effects in the Formation of Lyman
a in Prominences and Their Influence on the Ratio of Hα to Lα.
Authors: Milkey, R. W.; Heasley, J. N.; Schmahl, E. J.; Engvold, O.
1979phsp.coll...53M Altcode: 1979IAUCo..44...53M
No abstract at ADS
---------------------------------------------------------
Title: Discussion
Authors: Acton, L. W.; Heasley, J. N.; Sahal-Bréchot, S.; Stenflo, J.
1979phsp.coll...91A Altcode: 1979IAUCo..44...91A
No abstract at ADS
---------------------------------------------------------
Title: Structure and spectrum of quiescent
prominences. III. Application of theoretical models in helium
abundance determinations.
Authors: Heasley, J. N.; Milkey, R. W.
1978ApJ...221..677H Altcode:
The solar helium abundance has been investigated by using spectra
of quiescent prominences. The physical parameters (T, P, y, xi, M)
describing an isothermal and isobaric model of the prominence can be
determined from observations of hydrogen, helium, and ionized calcium
lines. Given these parameters, it may be shown that low values of
the helium abundance, such as those inferred from solar wind data,
are inconsistent with the prominence data. The helium-to-hydrogen
ratio is indicated to be 0.10 + or - 0.025 by number.
---------------------------------------------------------
Title: The origin of the broad-band circular polarization in sunspots.
Authors: Auer, L. H.; Heasley, J. N.
1978A&A....64...67A Altcode:
An analysis is performed to demonstrate that the net circular
polarization previously discovered in broadband observations of
sunspots cannot be explained by either a net continuum polarization
or Zeeman line splitting in a static atmosphere. It is shown that
a velocity gradient is necessary and sufficient for producing a net
circular polarization and that the observations can be explained if
macroscopic motions comparable to some unspecified thermal motions are
involved. The magnetic-field strength and flow velocities required to
explain the cited sunspot observations are estimated.
---------------------------------------------------------
Title: The fundamental bands of CO in Arcturus: evidence for an
inhomogeneous chromosphere.
Authors: Heasley, J. N.; Ridgway, S. T.; Carbon, D. F.; Milkey, R. W.;
Hall, D. N. B.
1978ApJ...219..970H Altcode:
We compare new high-spectral-resolution observations of the fundamental
vibration-rotation bands of CO in the Arcturus spectrum with synthetic
spectra for a representative set of existing model atmospheres of
this star. The Ayres and Linsky model of the lower chromosphere-upper
photosphere does not reproduce the observed spectrum in any respect. We
conclude that there is not a homogeneous chromosphere typical of that
model on Arcturus. It does not appear possible to reproduce both the Ca
II K line wings and the CO fundamental lines with a single-component
model. Several alternative sets of synthetic spectra are able to
reproduce the observed CO spectrum. We are not able at this time to
decide which of these most accurately represents the true atmospheric
structure of Arcturus because departures from LTE may be important in
the CO line formation. If such departures occur, the layers in which the
CO lines form will be hotter than those inferred from an LTE analysis.
---------------------------------------------------------
Title: Radiative transfer in cylindrical media.
Authors: Heasley, J. N.
1977JQSRT..18..541H Altcode:
A numerical method for the solution of the radiative transfer equation
in a circularly symmetric, cylindrical region is developed. The transfer
equation is formulated as a second-order differential equation resulting
in a set of tridiagonal difference equations. This form is particularly
well suited to line formation and energy balance calculations using the
complete linearization method. Several numerical examples are presented.
---------------------------------------------------------
Title: The determination of vector magnetic fields from Stokes
profiles.
Authors: Auer, L. H.; Heasley, J. N.; House, L. L.
1977SoPh...55...47A Altcode:
The application of Unno's (1956) solution of the transfer equation
for polarized radiation to the determination of thevector magnetic
field is investigated. An analysis procedure utilizing non-linear
least squares techniques is developed that allows one to automate the
reduction of measured spectral profiles of the Stokes parameters to
determine the field angles, strength as well as other parameters. The
method is applied to synthetic spectra generated using a model solar
atmosphere and yields results of remarkably high accuracy. The influence
of additional factors upon determination of the vector field are also
considered. These factors include effects of asymmetric profiles,
magneto-optical effects, magnetic field gradients, unresolved field
elements, scattered light, and instrumental noise.
---------------------------------------------------------
Title: Non-LTE line formation in the presence of magnetic fields.
Authors: Auer, L. H.; Heasley, J. N.; House, L. L.
1977ApJ...216..531A Altcode:
The equations of radiative transfer and statistical equilibrium in
the presence of a magnetic field are presented. A general difference
equation scheme for solving the vector transfer equation in Stokes
parameters, allowing for arbitrary variations of the magnetic field
and other quantities, is described. The solution of the Stokes non-LTE
problem for Ca II by the complete linearization method is described,
and numerical examples of the procedure are presented.
---------------------------------------------------------
Title: The effects of partial redistribution on facular K line
profiles.
Authors: Heasley, J. N.; Kneer, F.; Chapman, G. A.
1977SoPh...52..309H Altcode:
We present theoretical Ca II K-line profiles and filtergram contrasts
for several recent models of solar faculae. The line profiles vary
greatly between models and between complete and partial frequency
redistribution non-LTE calculations for any given model. The filtergram
contrasts are relatively insensitive to the line formation theory which
greatly simplifies the calculation for comparison with observations. All
of the models considered exhibit K-line contrasts smaller than the
mean value observed by Mehltretter.
---------------------------------------------------------
Title: The Ca II emission lines in quiescent prominences.
Authors: Heasley, J. N.; Milkey, R. W.; Engvold, O.
1977SoPh...51..315H Altcode:
Observations of the Ca II H, K, and infrared triplet lines are compared
with theoretical predictions from the slab models of Heasley and Milkey
(1976). While the theoretical models describe the hydrogen and helium
emission spectra of quiescent prominences satisfactorily the predicted
Ca II lines are systematically too bright. The most likely reason
for the discrepancy is the inapplicability of the symmetric slab
prominence model for lines which become even moderately optically
thick in prominences.
---------------------------------------------------------
Title: An Evaluation of a Model Chromosphere for Arcturus Using the
5-Micron Bands of Carbon Monoxide.
Authors: Heasley, J. N.; Ridgway, S. T.; Carbon, D. F.; Milkey, R. W.;
Hall, D. N. B.
1977BAAS....9..324H Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Structure and spectrum of quiescent prominences. II. Hydrogen
and helium spectra.
Authors: Heasley, J. N.; Milkey, R. W.
1976ApJ...210..827H Altcode:
Theoretical emission-line intensities for hydrogen and helium in models
of quiescent prominences have been computed and are compared with
the absolute intensities measured by Landman and Illing (1976). The
models required to match the observations have electron temperatures in
the range from 7500 to 9500 K and gas pressures equal to or slightly
greater than the coronal value. The calculations indicate a probable
lower limit of 0.05 to the helium-to-hydrogen number ratio for the
prominence studied.
---------------------------------------------------------
Title: Departures from LTE in the fundamental bands of CO in cool
stars.
Authors: Carbon, D. F.; Milkey, R. W.; Heasley, J. N.
1976ApJ...207..253C Altcode:
A method is presented for solving the coupled statistical equilibrium
and radiative transfer equations for the vibrational-rotational
transitions in the ground electronic state of CO. The technique is
subject to the assumption that the rotational levels within each
vibrational level are in LTE. We applied this method to three cool
stellar models within its range of applicability and find that the LTE
and non-LTE spectra are substantially different for the cooler models.
---------------------------------------------------------
Title: Structure and spectrum of quiescent prominences: energy
balance and hydrogen spectrum.
Authors: Heasley, J. N.; Mihalas, D.
1976ApJ...205..273H Altcode:
In this paper we present theoretical models of quiescent prominences
which satisfy the constraints of radiative, magnetohydrostatic,
and statistical equilibrium. We obtain reasonable models only if we
assume that the exciting ultraviolet radiation field can penetrate
diffusely into the slab, or that there is a source of nonradiative
energy input. The computed temperatures in our models are in good
agreement with observational estimates. The models reproduce most
observed features of these objects quite well, and should provide
a good starting point to study further the formation of prominence
spectra and the effects of nonradiative energy inputs.
---------------------------------------------------------
Title: An alternative formulation of the complete linearization
method for the solution of non-LTE transfer problems.
Authors: Auer, L. H.; Heasley, J. N.
1976ApJ...205..165A Altcode:
The complete linearization scheme for solving non-LTE transfer
problems is reformulated so that the procedure requires the same
amount of computation per iteration as the 'equivalent-two-level-atom'
approach. The reformulation involves making the timing linearly
proportional to the number of frequencies; the resulting system
of equations may be solved by a simple block iterative method. It
is noted that this reformulation has the same asymptotic timing
as integral-equation methods but retains the flexibility and
self-consistency of the original complete linearization scheme. The
proposed technique is used to solve a multitransition line-formation
problem for a five-level representation of the Ca II ion in the solar
chromosphere and to solve the resonance-doublet problem for Na I in
the chromosphere.
---------------------------------------------------------
Title: The fundamental bands of CO as chromospheric indicators in
late-type giant stars.
Authors: Heasley, J. N.; Milkey, R. W.
1976ApJ...205L..43H Altcode:
Synthetic spectra are presented for the vibrational-rotational
fundamental transitions in the ground electronic state of CO for the
upper-photosphere-lower-chromosphere atmospheric model of Arcturus
derived by Ayres (1975). It is found that the CO spectrum is formed
in LTE and the strongest molecular lines exhibit emission cores
reflecting the chromospheric temperature rise. The CO fundamental bands
offer an excellent observational probe for the presence of stellar
chromospheres and a consistency check for chromospheric models derived
from traditional chromospheric indicators.
---------------------------------------------------------
Title: Observation of Vector Magnetic Fields in Sunspots
Authors: House, L. L.; Baur, T. G.; Elmore, D. E.; Auer, L. W.;
Gurman, J.; Heasley, J. N.
1976BAAS....8..346H Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Formation of spectral lines with partial frequency
redistribution.
Authors: Heasley, J. N.; Kneer, F.
1976ApJ...203..660H Altcode:
A method for treating the effects of partial frequency redistribution
(PRD) in non-LTE radiative-transfer problems is presented in which the
rate equations may be kept in their usual form and the PRD effects may
be included by altering the form of the radiative-transfer equation. The
required modifications of the transfer and statistical-equilibrium
equations are outlined along with the changes these necessitate in
the complete linearization method. The formulation is compared with
that of Milkey et al. (1973), and sample PRD calculations are given
for the solar chromospheric Ly-alpha and Ca II K line profiles. The
results are found to be in excellent quantitative agreement with
previous computations.
---------------------------------------------------------
Title: Asymmetries of the solar Ca ii lines
Authors: Heasley, J. N.
1975SoPh...44..275H Altcode:
A theoretical study of the influence of propagating acoustic pulses in
the solar chromosphere upon the line profiles of the Ca II resonance
and infrared triplet lines has been made. The major objective has been
to explain the observed asymmetries seen in the cores of the H and K
lines and to predict the temporal behavior of the infrared lines caused
by passing acoustic or shock pulses. The velocities in the pulses,
calculated from weak shock theory, have been included consistently in
the non-LTE calculations.
---------------------------------------------------------
Title: Study of the He I emission lines in the solar
atmosphere. III. The triplet-singlet line intensity ratios in solar
prominences.
Authors: Heasley, J. N.; Tandberg-Hanssen, E.; Wagner, W. J.
1975A&A....40..391H Altcode:
Summary. We present observations of the He I spectrum for the quiescent
prominence of 4 November 1971. Integrated line-intensity ratios are
compared with theoretical calculations to obtain a hydrogen density of
1010 cm . The widths of He I and H I Balmer lines indicate an electron
temperature of 7000 K and a turbulent broading velocity of 8 km/s for
this object. Key words: helium lines prominences - excitation conditions
---------------------------------------------------------
Title: Non-LTE Line Formation in the Presence of a Magnetic Field
Authors: Auer, L. H.; Heasley, J. N.; House, L. L.
1975BAAS....7..349A Altcode:
No abstract at ADS
---------------------------------------------------------
Title: A non-LTE model stellar atmosphere computer program
Authors: Mihalas, D.; Heasley, J. N.; Auer, L. H.
1975STIN...7630128M Altcode:
A computer program was developed for calculating model atmospheres of
early-type stars subject to the constraints of radiative, hydrostatic,
and statistical equilibrium, by means of a complete-linearization
technique. This program is available through the NCAR High Altitude
Observatory's Radiative Transfer Library.
---------------------------------------------------------
Title: Theoretical Helium i Emission-Line Intensities for Quiescent
Prominences
Authors: Heasley, J. N.; Mihalas, Dimitri; Poland, A. I.
1974ApJ...192..181H Altcode:
Self-consistent solutions of the combined statistical equilibrium
and transfer equations have been carried out for a rather
complete multilevel, multi-ion model helium atom in model quiescent
prominences. The excitation and ionization of both He I and He ii were
considered simultaneously, and detailed calculations of the radiative
transfer in the resonance lines and ground-state continua of both
these ions were made, allowing for the effects of overlapping hydrogen
transitions. A large number of excited states have been included in the
computation, so that a fairly comprehensive set of predicted subordinate
line intensities are now available for comparison with observation. A
preliminary comparison of the predicted values with published singleti
triplet ratio observations shows good agreement for all the pairs of
lines considered. Subject headings: atomic processes - line formation -
prominences, solar
---------------------------------------------------------
Title: Theoretical helium I emission line intensities for quiescent
prominences.
Authors: Heasley, J. N.; Mihalas, D.; Poland, A. I.
1974BAAS....6..219H Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Theoretical Helium I Emission Line Intensities for Quiescent
Prominences.
Authors: Heasley, J. N.; Mihalas, D.; Poland, A. I.
1974BAAS....6..220H Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Helium Excitation in the Solar Chromosphere: he i in a
Homogeneous Chromosphere
Authors: Milkey, R. W.; Heasley, J. N.; Beebe, H. A.
1973ApJ...186.1043M Altcode:
We report kinetic equilibrium calculations for an He i atom with
13 bound levels in a homogeneous model chromosphere. We evaluate
the effectiveness of coronal radiation in producing ionization of
chromospheric helium and the methods of populating the excited levels
from which the visible and infrared transitions arise. The homogeneous
model gives a reasonable representation of quiet-Sun, disk-center
conditions, but fails to reproduce the eclipse data. Subject headings:
atomic processes - chromospheres, solar - spectra, solar
---------------------------------------------------------
Title: The Excitation of Chromospheric Helium
Authors: Milkey, R. W.; Heasley, J. N.; Beebe, H. A.
1973BAAS....5U.277M Altcode:
No abstract at ADS
---------------------------------------------------------
Title: An estimate of stellar wind mass loss during the red giant
phase of evolution
Authors: Heasley, J. N.; Mengel, J. G.
1972Obs....92...93H Altcode:
No abstract at ADS
---------------------------------------------------------
Title: A computational program for the solution of non-LTE transfer
problems by the complete linearization method
Authors: Auer, L. H.; Heasley, J. N.; Milkey, R. W.
1972CoKit.555.....A Altcode: 1972QB4.K55n555....
No abstract at ADS
---------------------------------------------------------
Title: Red giant evolution to the heliumflash of a super-metal-rich
star
Authors: Demarque, Pierre; Heasley, James N.
1971MNRAS.155...85D Altcode:
An evolutionary sequence is presented for a star of 1 19 M , with
composition parameters (X, Z) = ( , ). The evolution was followed
from the main sequence to the onset of convection in the core during
the helium flash. The resulting core mass at the helium flash, Me =
M is smaller than those found for Population II stars with the same
helium abundance. No mixing between hydrogen-rich envelope and the
helium core can be expected due to the non-central development of the
flash. The clumping of stars on the giant branch of old open clusters,
discussed by Cannon, is considered.
