%R 1995PASP..107..907R %T Photometric and Spectroscopic Distances for OB Stars: A Comparison %A B. CAMERON REED %B Reddenings, absolute magnitudes, and distances (D) based on both UBV-beta photometry and MK-system spectral classifications are computed and compared for 287 stars of spectral types 04-B2.5. While overall agreement is very good, D_UBV-beta/D_MK) = 1.06 +- 0.39 (s.d.), significant trends in photometric vs. spectroscopic absolute magnitudes and distances as a function of both absolute magnitude and photometric vs. spectroscopic luminosity classification are evident. Prescriptions as to whether one is likely to over- or under-estimate photometric as compared to spectroscopic distances in given circumstances are developes. Almost all of the standard deviation in D_UBV-beta/D-MK is attributable to differences in inferred absolute magnitudes. %R 1995PASP..107..914F %T Variability of IUE Spectra of the Pulsating Nucleus of the Planetary Nebula K 1-16 %A WALTER A. FEIBELMAN, JAMES B. KALER, HOWARD E. BOND, and ALBERT D. GRAUER %B We report on some subtle changes which were detected in old IUE low dispersion spectra of the pulsating central star of the planetary nebula K 1-16. Although most of the data were taken more than ten years ago, the improved data reduction techniques and more accurate line identifications that have become available only recently permit measurement of variability in absorption lines. These changes are suspected of being caused by variations of O VI and high-excitation C IV transitions that on low-dispersion spectra are unresolved from interstellar Si II and may also mimic He II lambda-1640 absorption. We compare features in low- and high-resolution spectra of K 1-16 with those found in other PG 1159- and O VI-type central stars. %R 1995PASP..107..927C %T X-Ray Discovery of a Hot PG1159 Star %A RX J0122.9-7521, A. P. COWLEY, P. C. SCHMIDTKE, J. B. HUTCHINGS, and D. CRAMPTON %B The supersoft X-ray source RX J0122.9-7521 has been optically identified with an extremeley hot PG1159 star. Its spectrum shows high excitation emission lines from which we estimate Teff ~140,000K and log g~7. Limited photometry taken during six nights shows no conclusive variability, but we cannot rule out short-period, low-amplitude pulsations (P<5 min) as are found in some PG1159 stars. There is some evidence for variations in the emission-line strengths, but higher quality spectra are needed to confirm this. %R 1995PASP..107..931H %T An X-Ray Selected White Dwarf + M Dwarf Binary: RX J0458.9-6628 %A J. B. HUTCHINGS, D. CRAMPTON, A. P. COWLEY, P. C. SCHMIDTKE, T. K. MCGRATH, and Y.-H. CHU %B A new close binary containing a DA white dwarf and a dwarf M star has been identified from its X-ray emission. The spectra of both stars are seen with about equal flux at ~4600A. H and Ca II emission, associated with the M star, is also present. Limited photometry does not show any variability, but radial velocity changes indicate the binary period lies in the range from ~0.7 to a few days. The small observed velocity range and lack of pronounced emission line changes suggest a low inclination system. The DA velocities are poorly determined but suggest the unlikely conclusion that it may be the less massive star in the binary. %R 1995PASP..107..937D %T C J0907-372 (Pyxis): A New Distant Galactic Globular Cluster %A G. S. DA COSTA %B The prime focus camera of the Anglo-Australian Telescope has been used to image the object listed by Weinberger (PASP, 107, 58 [1995]) as a possible distant star cluster or dwarf spheroidal galaxy. The CCD data reveal this object to be a distant globular cluster of low central concentration. In particular, the color-magnitude diagram for the cluster core shows a sparse giant branch, a prominent red horizontal branch at R=18.75 and a main sequence turnoff near the limit of the data at R=22.0. A population of possible blue stragglers is also evident. Based on comparisons with the giant branches of standard globular clusters, the reddening to this cluster, designated C J0907-372 (Pyxis), is estimated to be 0.25 <= E(B-V) <= 0.40. The cluster is then approximately 35 kpc from the Sun and 37 kpc from the galactic center. With a core radius of ~14 pc, an estimated absolute magnitude M_V=-5.7 and a dominant red horizontal branch, C J0907-372 (Pyxis) has very similar properties to the other low luminosity globular clusters of the outer galactic halo. %R 1995PASP..107..945F %T Galaxy Colors in Various Photometric Band Systems %A M. FUKUGITA, K. SHIMASAKU, and T. ICHIKAWA %B A study is made of stellar and galaxy colors using a spectrophotometric synethesis technique. We show that use of good color response functions and a modern determination of the spectroscopic energy distribution for a alpha-Lyr gives synthetic colors in a good agreement with photometric observations to about 0.05 mag. The synthetic method then is applied to sutdy galaxy colors using the spectrophotometric atlas of Kennicutt (1992), and a comparison is made with observed galaxy colors. The K-correction is calculated and compared with that of Coleman, Wu and Weedman (1980). We then study colors of galaxies in various photometric band systems and obtain color transformation laws, which enable us to find offsets among different systems. We include 48 photometric bands in our study. %R 1995PASP..107..959A %T Spectral Emission of a Sample of IRAS Galaxies. II %A E. L. AGUERO, F. SUAREZ, and S. PAOLANTONIO %B Observations of seven objects selected from the de Grijp et al. Catalog of AGN candidates (1987) and two from the list of Maia et al. (1987) are reported. From their optical spectral characteristics they are classified according to their degree of nuclear activity: two of them as Seyfert 2 types, two others as Seyfert 1.9 types, one as a Liner, adn three as H II region-like galaxies; the reamining one turns out to be a star. Far infrared properties are also used to analyze these objects. Very good correlations between the far IR luminosity and H-alpha and [O III] lambda-5007 luminosities are found for the Seyfert galaxies. The far infrared luminosity of these seems to depend on both, the amount of the dust present and strongly on the number of ionizing photons. %R 1995PASP..107..966V %T Determining Spectrometer Instrumental Profiles Using FTS Reference Spectra %A JEFF A. VALENTI, R. PAUL BUTLER, and GEOFFREY W. MARCY %B We describe a new technique for determining the instrumental profile (IP) of an astronomical spectrometer. A known instrinsic spectrum of a reference source is convoluted with a parameterized IP and then compared to a spectrum obtained with the spectrometer to be characterized. Nonlinear least-squares (NLLS) optimization is used to solve for the analytic IP that best reproduces the observed spectrum. This technique is most effective for characterizing the central portion of the IP, out to 1% of the peak. IP recovery is demonstrated using both the Sun and an I2 absorption cell as reference spectra. We also describe a second technique employing singular value decomposition (SVD) to recover an approximate IP by directly inverting a discretized convolution. This second technique is less contstrained and therefore gives poorer results than NLLS, but it is useful when the form of the IP is unknown. Using the NLLS technique, we demonstrate by example that the IP is a function of position in the format of cross-dispersed echelle spectrometers. We also compare our results with laser and thorium emission line profiles. Finally, we present the IP for a range of positions in the format of the Hamilton echelle spectrograph at Lick Observatory and the HIRES echelle at the Keck 10-m telescope. %R 1995PASP..107..977T %T Papers and Citations Resulting from Data Collected at Large, American Optical Telescopes %A VIRGINIA TRIMBLE %B Data compiled about a decade ago and pertaining to 1980-84 showed that the large, general-access American optical teelscopes (the 4-meters at Kitt Peak and Cerro-Tololo) were at least as productive in published papers, pages, and citations as the large, privately-owned ones (3-meter at Lick and 5-meter at Palomar). A current very similar compilation shows that the relative contributions of these four telescopes have changed rather little, though several additional ones are now major contributors. For both papers and apges, the current ranking from most to least productive is CTIO, Palomar, KPNO, and Lick. (KPNO moves ahead of Palomar in numbers of citations.) If the numbers are normalized to the area of the primary mirror, the rankings change radically, and Lick becomes the most productive of the four in both 1980-81 and 1990-91. The average number of citations per paper per year is nearly unchanged at a bit more than four. %R 1995PASP..107..981K %T A Workshop on High-Resolution Spectroscopy with Very Large Telescopes: An Introduction to the Summarizing Reports %A ROBERT P. KRAFT %B Introduction to the Summarizing Reports. %R 1995PASP..107..983P %T High-Resolution Spectrographs for Large Telescopes %A C. PILACHOWSKI, H. DEKKER K. HINKLE, R. TULL, S. VOGT, D. D. WALKER, F. DIEGO, and R. ANGEL %B Spectrographs designed or built for the Keck, Gemini, Hobby-Eberly, MMT, and ESO Very Large Telescopes are described and compared to demonstrate principles and constraints in the design of spectrographs for 8-m to 10-m class telescopes. %R 1995PASP..107..990S %T Properties of Echelle Spectrographs: The Transition from 4-m Telescopes to Very Large Telescopes %A NICHOLAS B. SUNTZEFF %B One of the goals of this conference is to discuss the range of characteristics that a high dispersion spectrograph must have to allow astronomers to work on the exciting scientific problems that will be done with very large telescopes. Most echelle work in the last two decades has been done at resolutions of ~2000 and it is anticipated that most future work will be done at resolutions near 5000. The expected designs for echelle spectrographs will not be ideal for most radial velocity work, where the detector noise and dark count will compromise the typical low signal-to-noise spectra used for velocity measurements. %R 1995PASP..107..994D %T Stellar Physics Using High-Resolution Spectroscopy with Large Telescopes %A PIERRE DEMARQUE %B The traditional high resolution domain of stellar physics will be profoundly affected by the deployment of 8-10 meter class telescopes. We discuss here some of the advances anticipated in the fields of stellar convection, seismology and magentic structures. Also discussed are the tests of stellar evolution and star formation processes that one may expect based on high resolution observations of radial velocity, Doppler imaging, and chemical abundances. %R 1995PASP..107..997S %T Stellar Population and Abundance Studies at High Resolution with Very Large Telescopes %A C. SNEDEN, G. BASRI, A. M. BOESGAARD, J. A. BROWN, B. W. CARNEY, R. P. KRAFT, V. V. SMITH, and N. B. SUNTZEFF %B New opportunities for exploring stellar populations at high spectral resolution with the new generation of very large optical telescopes are reviewed. This summary will discuss papers presented at the Tucson workshop, High Resolution Spectroscopy with Very Large Telescopes, on abundance and kinematic information for relatively cool stars of the field and clusters of our Galaxy and in the Magellanic Clouds. %R 1995PASP..107.1003K %T High-Resolution Spectroscopy of the Interstellar Medium %A ROBERT C. KENNICUTT, JR., DAVID M. MEYER, ROGER A. CHEVALIER, and LAURA DANLY %B High-resolution spectroscopy of interstellar absorption and emission lines provides information on the physical conditions and dynamical evolution of the ISM in our Galaxy and other nearby galaxies. We describe several examples of applications, and briefly address the impact of ISM applications on instrument design. %R 1995PASP..107.1007S %T High-Resolution Spectroscopy of Quasars and Quasar Absorption-Line Systems %A J. MICHAEL SHULL %B I provide a summary of the session on "Active Galactic Nuclei and Quasar Absorption Lines," with contributions by J. Wampler, A. Wolfe, W. Sargent, J. Bechtold, M. Pettini, and M. Shull. The topics included new observations of QSO absorption lines by the Keck Telescope HIRES spectrometer and the Hubble Space Telescope. An overview of the major scientific issues in this field is followed by a brief summary of a panel discussion that addressed future instrumental possibilities that could answer some of these questions. %R 1995PASP..107.1012T %T A Low-Resolution View of High-Resolution Spectroscopy %A VIRGINIA TRIMBLE %B The enormous cost of even relatively simple focal-plane instruments for 8 +- 2 meter telescopes is, inevitably, acting as a driver to produce very general-purpose spectrographs for each of them. Somewhat unexpectedly, the result seems to have been a convergence on very similar, cross-dispersed, R = lambda/Delta-lambda ~10^5 Echelles for nearly every such telescope in use, under construction, development, or consideration. Such spectrographs are well matched to studies of small numbers of relatively bright point sources (stars or QSOs) directed at understanding either the sources themselves or intervening gas responsible for absorption lines. They are much less well suited to studies of extended objects (nebulae, galaxies) and to studies of populations of stars or galaxies, including those in clusters, and to studies of very faint objects, where accurate sky subtraction is vital. Adaption of the existing and contemplated instruments to long-slit, multi-slit, and multi-object use apparently carries high prices in lost photons, increased noise, and increased exposure time. %R 1995PASP..107.1016H %T Old Open Clusters as Probes of Stellar and Galactic Disk Evolution %A BETH HUFNAGEL %B Open clusters have traditionally been used to investigate the chemical evolution of the Galactic disk, using the assumption that they reflect the chemical abundance of the interstellar medium (ISM). This assumption was tested by analyzing two samples of ~20 old open cluster spectra, one of evolved, red-horizontal-branch stars in the ~10-Gyr-old NGC 6791, and the second of unevolved G-dwarfs in the younger, ~4.5-Gyr-old M 67. Unlike many globular clusters, the band and line strengths of CN, CH, Ca, and Fe show neither a bimodal distribution, nor a CN-to-CH anticorrelation. However, the data for the evolved stars of NGC 6791 do provide evidence for a dispersion in CN band strengths. If the explanation for this is that stellar evolution after ~4.5 Gyr produces CN inhomogeneities, the CN-band strengths of very old, evolved stars are questionable tracers of the initial chemical abundance of the ISM. \par Stellar clusters are often used to study stellar evolution because such stars are coeval and equidistant. The results are then extrapolated to disk stars with little proof that the old disk stars originated in clusters. An essential link may be moving groups, stars that are not in close physical proximity but have similar kinematics and [Fe/H]. The age of eight HR 1614 Moving Group dwarfs was investigated, and it was determined that all eight are at least 3 Gyr old. This supports the scenario that many of the disk field stars formed in open clusters which subsequently were disrupted. \par Theories about Galactic disk evolution can be evaluated by comparing their predictions to the old open cluster system. The "inside-out" type of theory predicts that the ISM in the inner part of the Galactic disk is older and more chemically evolved than that of the outer part. Two samples of old open clusters, one from the inner and one from the outer disk, had significantly different mean [Fe/H] values, but similar mean ages. The former is in accordance with inside-out theories: the latter is not. The system of old open clusters appears to have extended to a larger radial distance ~5-7 Gyr ago, also not consistent with inside-out theories. These results can not be attributed to the preferential destruction of inner-disk open clusters.