%...Journal: PASP
%R=BibCode
%A=Authors
%B=Abstract
%c=Copyright
%D=Date of publication
%E=Electronic file
%F=Original File
%I=Institute and/or Footnotes
%J-last page
%K=Keywords
%T=Title

%R 1999PASP..111..385T
%F ori/PASPv111n758
%J-437
%T Astrophysics in 1998. (Invited Review).
%A Trimble, Virginia (1)
%A Aschwanden, Markus (2)
%B  From Alpha (Orionis and the parameter in mixing-length theory) to Omega
   (Centauri and the density of the universe), the Greeks had a letter for it.
   In between, we look at the Sun and planets, some very distant galaxies and
   nearby stars, neutrinos, gamma rays, and some of the anomalies that arise
   in a very large universe being studied by roughly one astronomer per 10^7^
   Galactic stars.
%K Invited Reviews
%I (1) Department of Astronomy, University of Maryland, College Park, MD
   20742; and Department of Physics and Astronomy, University of California,
   Irvine, Irvine, CA 92697.
%I (2) Lockheed-Martin ATC Solar and Astrophysics Laboratory, Department
   H1-12, Building 252, 3251 Hanover Street, Palo Alto, CA 94304.

%R 1999PASP..111..438F
%F ori/PASPv111n758
%J-452
%T The Updated Zwicky Catalog (UZC)(1,)(2,)(3).
%A Falco, Emilio E.
%A Kurtz, Michael J.
%A Geller, Margaret J.
%A Huchra, John P.
%A Peters, James
%A Berlind, Perry
%A Mink, Douglas J.
%A Tokarz, Susan P.,
%A Elwell, Barbara
%I Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge,
   MA 02138 (falco@cfa.harvard.edu)
%B  The Zwicky Catalog of galaxies (ZC), with m_Zw_{<=}15.5, has been the
   basis for the Center for Astrophysics (CfA) redshift surveys. To date, analyses
   of the ZC and redshift surveys based on it have relied on heterogeneous sets
   of galaxy coordinates and redshifts. Here we correct some of the inadequacies
   of previous catalogs by providing (1) coordinates with {<~}2" errors for
   all of the 19,369 catalog galaxies, (2) homogeneously estimated redshifts
   for the majority (98%) of the data taken at the CfA (14,632 spectra), and
   (3) an estimate of the remaining ``blunder'' rate for both the CfA redshifts
   and for those compiled from the literature. For the reanalyzed CfA data we
   include a calibrated, uniformly determined error and an indication of the
   presence of emission lines in each spectrum. We provide redshifts for 7257
   galaxies in the CfA2 redshift survey not previously published; for another
   5625 CfA redshifts we list the remeasured or uniformly rereduced value. Among
   our new measurements, 1807 are members of UZC ``multiplets'' associated with
   the original Zwicky catalog position in the coordinate range where the catalog
   is 98% complete. These multiplets provide new candidates for examination
   of tidal interactions among galaxies. All of the new redshifts correspond
   to UZC galaxies with properties recorded in the CfA redshift compilation
   known as ZCAT. About 1000 of our new measurements were motivated either by
   inadequate signal-to-noise in the original spectrum or by an ambiguous identification
   of the galaxy associated with a ZCAT redshift. The redshift catalog we include
   here is ~96% complete to m_Zw_{<=}15.5 and ~98% complete (12,925 galaxies
   out of a total of 13,150) for the right ascension ranges 20^h^{>=}{alpha}_1950_{<=}4^h^
   and 8^h^{>=}{alpha}_1950_{<=}17^h^ and declination range -2{deg}.5{<=}{delta}_1950_{<=}50{deg}.
   This more complete region includes all of the CfA2 survey as analyzed to
   date. The Great Wall structure persists throughout the northern survey region.
%K Astrometry
%K Catalogs
%K Cosmology: Observations
%K Galaxies: Distances and Redshifts
%I (1) Dedicated to the memory of Jim Peters, whose friendship, skill,
   dedication were essential to this work.
%I (2) This research made use of the NASA/IPAC Extragalactic Database (NED),
   which is operated by the Jet Propulsion Laboratory, Caltech, under contract
   with the National Aeronautics and Space Administration.
%I (3) We have made use in part of finder chart(s) obtained using the Guide
   Stars Selection System Astrometric Support Program developed at the Space
   Telescope Science Institute (STScI is operated by the Association of Universities
   for Research in Astronomy, Inc., for NASA).

%R 1999PASP..111..453S
%F ori/PASPv111n758
%J-464
%T Analysis of Spatially Resolved Emission Lines in the Spectra of Distant Galaxies.
%A Simard, Luc (1)(2)
%A Pritchet, Christopher J. (1)
%I Department of Physics and Astronomy, University of Victoria, P.O. Box 3055,
   Victoria, BC V8W 3P6, Canada; (simard@ucolick.org), (pritchet@uvastro.phys.uvic.ca)
%B  Internal kinematics is rapidly becoming an important tool for understanding
   the nature and evolution of distant galaxies. However, the very low signal-to-noise
   ratios involved in these observations pose challenges to reduction techniques.
   We present a synthetic rotation curve technique to analyze spatially resolved
   emission lines from faint galaxies. This algorithm takes into account important
   variables, such as intrinsic velocity field, spatial distribution of the
   line-emitting gas, telescope point-spread function, spectrograph slit width,
   and instrumental profiles. Our technique makes use of the Metropolis algorithm
   to find the best model parameter values and their confidence intervals. This
   algorithm proves to be more robust in low signal-to-noise regimes than least-squares
   fitting. The technique has been tested on a large set of rotation curve simulations
   and has been successfully used to analyze a sample of 22 field galaxies in
   the redshift range 0.25<z<0.45.
%K Galaxies: Kinematics and Dynamics
%K Methods: Data Analysis
%I (1) Visiting Astronomer, Canada-France-Hawaii Telescope, which is operated
   by the National Research Council of Canada, le Centre National de la Recherche
   Scientifique of France, and the University of Hawaii.
%I (2) Present address: University of California/Lick Observatory, Santa
   Cruz, CA 95064.

%R 1999PASP..111..465S
%F ori/PASPv111n758
%J-481
%T Emission-Line Properties of the Large Magellanic Cloud Bubble N70.
%A Skelton, Brooke P.
%I Astronomy Department, University of Washington, Seattle, WA 98195; (skelton@astro.washington.edu)
%A Waller, William H. (1)(2)
%I Raytheon STX Corporation, NASA Goddard Space Flight Center, Laboratory for
   Astronomy and Solar Physics, Code 681, Greenbelt, MD 20771
%A Gelderman, Richard F. (3)
%I National Research Council and NASA Goddard Space Flight Center, Laboratory
   for Astronomy and Solar Physics, Code 681, Greenbelt, MD 20771
%A Brown, Larry W.
%A Woodgate, Bruce E.
%I NASA Goddard Space Flight Center, Laboratory for Astronomy and Solar Physics,
   Code 681, Greenbelt, MD 20771
%A Caulet, Adeline (1)
%I Astronomy Department, University of Illinois, Urbana, IL 61801
%A Schommer, Robert A.
%I National Optical Astronomy Observatories, Cerro Tololo Inter-American Observatory,
   Casilla 603, La Serena, Chile
%B  We present a spectrophotometric imaging study of the emission bubble
   N70 (DEM 301) in the Large Magellanic Cloud. N70 is approximately 100 pc
   in size with a nearly circular shell-like morphology. The nebular emission
   is powered by an uncertain combination of EUV photons, intense winds, and
   supernova shock waves from the central population of high-mass stars (the
   OB association LH 114). We have obtained narrowband images (FWHM~6 {AA}) of
   N70 in the light of H{alpha} {lambda}6563, [N II] {lambda}6584, [S II] {lambda}{lambda}6717,
   6731, and [O III] {lambda}5007, along with the corresponding red and green
   continua. The resulting line fluxes and flux ratios are used to derive ionization
   rates, nebular densities, volume filling fractions, and excitation indices.
   The photoionizing luminosity inferred from the embedded stellar population
   is more than adequate to account for the observed hydrogen ionization rate.\par
   We compare the emission-line photometry with that derived from similar imaging
   of the Orion Nebula and with data collected from the literature on other
   emission-line regions in the LMC. Compared with the Orion Nebula, N70 shows
   much higher [S II]/H{alpha} intensity ratios that increase smoothly with
   radius--from less than 0.3 near the center to greater than 1.0 toward the
   outer filamentary shell. The measured intensity ratios in N70 more closely
   match the range of excitation spanned by giant and supergiant H II shells
   and by some of the supernova remnants observed in the LMC. The contending
   ionization and excitation processes in the interior and outer shell of N70
   are evaluated in terms of the available data. EUV photons probably contribute
   most of the inner nebula's ionization, whereas a combination of photoionization
   plus collisional ionization and excitation of sulfur atoms by low-velocity
   shocks seems to best fit the emission-line luminosities and intensity ratios
   observed in the outer shell. Considerations of the radiative and mechanical
   energetics that are involved may indicate the need for one or two supernova
   explosions having occurred during the last ~Myr.
%K Galaxies: Magellanic Clouds
%I (1) Visiting Astronomer, Cerro Tololo Inter-American Observatory. CTIO
   is operated by AURA, Inc., under contract to the National Science Foundation.
%I (2) Current address: Harvard Smithsonian Center for Astrophysics, 60
   Garden Street, Cambridge, MA 02138.
%I (3) Current address: Western Kentucky University, Department of Physics
   and Astronomy, Bowling Green, KY 42101-3576.

%R 1999PASP..111..482S
%F ori/PASPv111n758
%J-488
%T Lithium in the Super-Beryllium-rich Hg-Mn Stars HR 6158 and HR 8915.
%A Stephens, Alex
%I Institute for Astronomy, University of Hawai`i at M{amacr}noa, 2680 Woodlawn
   Drive, Honolulu, HI 96822; (alex@galileo.ifa.hawaii.edu)
%A Deliyannis, Constantine P.
%I Department of Astronomy, Indiana University, 319 Swain West, Bloomington,
   IN 47405; (con@athena.astro.indiana.edu)
%B  The chemically peculiar stars that inhabit the upper main sequence exhibit
   very extreme enhancements and deficiencies of several elements. In all likelihood,
   the primary cause of these anomalies is radiatively driven diffusion, although
   other mechanisms may also be important--such as mass loss and various kinds
   of mixing. Only by examining as many elements as possible will a cohesive
   theory explaining these abundance oddities materialize. To this end, we present
   high-resolution (R{approx}62,500), high signal-to-noise ratio (S/N pixel^-1^{approx}120)
   observations of the 6708 {AA} Li I resonance doublet in a pair of Hg-Mn stars.
   No record of a lithium detection has been found for this type of chemically
   peculiar star. The atmospheres of the two program stars (HR 6158=28 Her=HD
   149212; HR 8915=69 Peg=HD 220933) contain an inordinate amount of beryllium
   (Be); in fact, the Be abundances in these stars are among the highest known.
   While the LTE concentration of Be is several thousand times larger than cosmic
   {lsqb}A(Be)_i_{approx}1.27{rsqb} in both stars, lithium (Li) is detected
   in neither HR 6158 nor HR 8915. The calculated 3 {sigma} (99{percnt} confidence
   level) upper limits place the maximum Li enhancements at 50 times and 80
   times cosmic {lsqb}A(Li)_i_{approx}3.23{rsqb} for HR 6158 and HR 8915, respectively,
   or {approx}100 times {\em smaller} than the Be overabundances. These Li upper
   limits, which argue against a ``nucleosynthesis'' origin for the Be surfeit,
   provide yet another means of constraining the physical process (or processes)
   responsible for the Hg-Mn phenomenon in some A stars.
%K Stars: Abundances
%K Stars: Chemically Peculiar

%R 1999PASP..111..489M
%F ori/PASPv111n758
%J-493
%T The Slope of the RR Lyrae Variables M_v_,f{lsqb}Fe/H{rsqb} Relation.
%A McNamara, D.H.
%I Department of Physics and Astronomy, Brigham Young University, Provo, UT
   84602; (mcnamara@astro.byu.edu)
%B  We discuss the slope of the RR Lyrae variables M_v_,{lsqb}Fe/H{rsqb}
   relation by two independent methods. We show that the slope is 0.32 if Baade-Wesselink
   M_v_ values are used only for stars with [Fe/H]>-1.5. Because the metal abundances
   of the variables are constant or nearly so for a large range of periods (the
   Oosterhoff I variables with log {\em P} values in the range -0.29 to -0.215),
   a flat section in the M_v_,{lsqb}Fe/H{rsqb} relation is produced that tends
   to reduce the slope if stars with log[Fe/H]<-1.5 are included in the solution.
   An analysis of data on RR Lyrae stars in the Galactic bulge yields a slope
   of ~0.31.
%K Stars: Horizontal-Branch
%K Stars: Variables: RR Lyrae Variable

%R 1999PASP..111..494M
%F ori/PASPv111n758
%J-509
%T Multicolor Polarimetry of Selected Be Stars: 1995-1998.
%A McDavid, David
%I Limber Observatory, Timber Creek Road, P.O. Box 63599, Pipe Creek TX 78063-3599;
   (mcdavid@limber.org)
%B  A new polarimeter called AnyPol has been used at Limber Observatory
   for 4 yr to monitor annually the broadband linear polarization of a sample
   of bright northern Be stars. This is the fourth report on a program started
   in 1985 at McDonald Observatory and the first one to come entirely from the
   new installation. Although no variability was detected at the 3 {sigma} level
   during the current reporting period, analysis of the full 13 yr data set
   is beginning to reveal hints of long-term variability that may provide clues
   for understanding the Be phenomenon.
%K Instrumentation: Polarimeters
%K Stars: Emission-Line, Be
%K Stars: Evolution
%K Stars: Mass Loss
%K Techniques: Polarimetric

%R 1999PASP..111..510K
%F ori/PASPv111n758
%J-511
%T Level of Negative Sidelobes in an Array Beam.
%A Kogan, L.
%I National Radio Astronomy Observatory,(1) Socorro, NM 87801 (lkogan@aoc.nrao.edu)
%B  It is shown that {\em the level of negative sidelobes of an array}'{\em
   s beam in the snapshot observation does not depend on the array configuration
   and is determined completely by the number of the elements at the array}.
   This level is not less than -1/N-1 for any array's beam, where {\em N} is
   the number of elements at the array. For the central symmetry arrays, all
   negative sidelobes are tangent to the horizontal line at the level -1/N-1.
   For large {\em N}, positive sidelobes are bigger than negative ones (in absolute
   values). For example, for VLA (N=27) and VLBA (N=10), the value of negative
   sidelobes should be 0.038 and 0.11, respectively, for any configuration.
%K Instrumentation: Interferometers
%I (1) The National Radio Astronomy Observatory is a facility of the National
   Science Foundation, operated under cooperative agreement by Associated Universities,
   Inc.

%R 1999PASP..111..512L
%F ori/PASPv111n758
%J-521
%T Refraction by Earth's Atmosphere near 12 Microns.
%A Livengood, T.A. (1)
%A Fast, K.E. (1)
%I Department of Astronomy, University of Maryland, College Park at Code 693,
   NASA Goddard Space Flight Center, Greenbelt, MD 20771; (timothy.a.livengood@gsfc.nasa.gov),
   (kelly.fast@gsfc.nasa.gov)
%A Kostiuk, T. (1)
%A Espenak, F. (1)
%A Buhl, D. (1)
%I Code 693, NASA Goddard Space Flight Center, Greenbelt, MD 20771; (kostiuk@gsfc.nasa.gov),
   (espenak@gsfc.nasa.gov), (u32db@gsfc.nasa.gov)
%A Goldstein, J.J. (1)
%A Hewagama, T. (1)
%I Challenger Center for Space Science Education, 1029 North Royal Street, Suite
   300, Alexandria, VA 22314; (jgoldstein@challenger.org), (hewagama@gsfc.nasa.gov)
%A Ro, K.H. (1)
%I School of Electrical Engineering, Cornell University, Ithaca, NY 14850; (khr1@cornell
   edu)
%B  We have measured chromatic differential refraction of astronomical images
   by the Earth's atmosphere, comparing visible light at 500-600 nm with infrared
   near 12 {mu}m, and found the index of refraction near 12 {mu}m to be greater
   than predicted by the dispersion relation in common use. The {\em differential}
   refraction between visible and 12 {mu}m thus is smaller than the extrapolated
   difference. At Mauna Kea, the empirical differential refraction at 45{deg} from
   zenith was measured at 0".28+/-0".28 (3 {sigma}) on one occasion, compared
   to an expected differential refraction of 0".63-0".69. Refractivity scales
   linearly with barometric pressure, and thus the inaccuracy is more severe
   at lower altitude observatories. The pointing error from inaccurate correction
   for differential refraction is comparable to the point spread function width
   of an 8-10 m telescope in this wavelength range. Even on smaller telescopes,
   accurate correction for differential refraction is necessary to guide small-aperture
   spectrophotometry or to register mid-infrared imaging with visible-light
   structures.
%K Infrared Radiation
%K Instrumentation: Miscellaneous
%K Methods: Observational
%K Physical Data and Processes
%K Techniques: Miscellaneous
%I (1) Visiting astronomer at the NASA Infrared Telescope Facility, operated
   by the University of Hawaii under contract to the National Aeronautics and
   Space Administration.

%R 1999PASP..111..522P
%F ori/PASPv111n758
%J-522
%T Surface Inhomogeneities and Semiempirical Modeling of Metal-poor Stellar
   Photospheres. (Dissertation Summary).
%A Prieto, Carlos Allende
%I Current address: McDonald Observatory, University of Texas, RLM 15.308, Austin,
   TX 78712-1083; (callende@astro.as.utexas.edu)Thesis work conducted at Instituto
   de Astrof\'isica de Canarias, SpainPh.D. Thesis directed by Ram\'on J. Garc\'ia
   L\'opez; Ph.D. degree awarded 1998
%K Stars: Atmospheres
%K Stars: Abundances
%K Stars: Population II
%K stars: individual (Gmb 1830, HD 140283)
%K Sun
%K Surveys

%R 1999PASP..111..523B
%F ori/PASPv111n758
%J-523
%T The Evolution of Galaxies on Cosmological Timescales(1). (Conference Highlights).
%A Beckman, J.E.
%A Mahoney, T.J.
%I Instituto de Astrofisica de Canarias, Tenerife, Spain
%I (1) Conference was held in Puerto de la Cruz, Tenerife, Spain in 1998
   December. Proceedings will be edited by J. E. Beckman and T. J. Mahoney and
   published in the ASP Conference Series.