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University of Pittsburgh Department of Physics and Astronomy Pittsburgh, Pennsylvania 15260

This report covers the period from 9/94 to 9/95. due to unexpected surgery, from which he has since fully recovered. Several topical sessions were organized by Uni- 1. PERSONNEL versity of Pittsburgh faculty. Hazard and D.A. Turnshek or- ganized a session on the ‘‘Status of Large Telescope Projects, The faculty in the astronomy group of the Department of Instrumentation and Plans for Large Science Programs in the Physics and Astronomy included F.H. Briggs ͑until 12/94͒, Areas of Wide-Field Surveys,’’ D.A. Turnshek, Khersonsky, G. Gatewood, C. Hazard, D.J. Hillier, R.E. Schulte-Ladbeck, and Rao organized a session on ‘‘QSO Absorption-Line and D.A. Turnshek. Briggs joined the Kapteyn Astronomical Studies with HST and Keck,’’ Espey held one on ‘‘Metallic- Institute of the Univeristy of Groningen, The Netherlands, ity in the Near Active Galactic Nuclear Environment,’’ and where he holds the chair of professor of extragalactic radio Schulte-Ladbeck hosted ‘‘First results from Astro-2’’ and co- astronomy. He continues in an adjunct position at Pittsburgh. hosted ‘‘Supercomputer Applications in Astronomy.’’ The V.K. Khersonsky held the position of visiting professor, J. meeting attracted 774 participants. Stein that of adjunct assistant professor, and B.R. Espey that of research assistant professor. S. Rao continued as a re- search associate. D.L. Miller was appointed research associ- 3. FACILITIES ate starting 9/94. S. Sherer assumed the position of research Allegheny Observatory and a system of workstations are specialist. the main facilities of the astronomy group at the University The following graduate students worked with astronomy of Pittsburgh. faculty this year: J. Birriel, J. Busche, J. Herald, M. Kopko, At Allegheny Observatory, the drive on the Keeler 0.76-m R. Kurosawa, E. Lauzier, L. Lee, E. Monier, C. Sirola, A. reflector was improved. Snyder Hale, D.D. Snyder Hale, E. Sorar, and S. Taramopou- A two-sensor version of a Multichannel Astrometric Pho- los. tometer ͑MAP͒ channel was built and tested. The Image E. Sorar received the Ph.D. after successfully defending Trailer 2 ͑IT2͒ measures the relative simultaneous position of his thesis entitled ‘‘A New Method for Deep Radio Surveys a star in two wavelengths. A Multichannel Astrometric Pho- in the 21-cm Line and the Application to Two HI Surveys tometer incorporating a number of such channels could be Using the Arecibo Telescope’’ prepared under the supervi- used to obtain astrometric positions that are free of differen- sion of Briggs. D.D. Snyder Haler, a student advised by tial chromatic aberration. Successful tests of the instrument Gatewood, obtained the Master of Science degree, with a were conducted in August. thesis on ‘‘Instrumentation for Infrared Stellar Interferom- etry.’’ A. Vaidya presented a thesis on ‘‘Investigations into 4. STELLAR ASTRONOMY the Circumstellar Environment of Herbig Ae/Be Stars’’ pre- Gatewood continued to use the Multichannel Astrometric pared under the supervision of Schulte-Ladbeck, and re- Photometer ͑MAP͒, which is mounted as a dedicated instru- ceived the degree of Bachelor of Philosophy in Physics & ment on the Allegheny Observatory’s 30-inch red-light re- Astronomy and Mathematics from the Honors College. fractor, in parallax and planetary detection programs. The The following undergraduate students worked in our observational program continued at full speed with approxi- group: M. Anticole, J. Hill, A. Landrum ͑Mt. Holycke͒,P. mately 3000 MAP ruling sweeps being recorded during the Morris, D. Noll, and A. Vaidya. reporting period. On March 2, 1995, the Astro-2 space shuttle observatory TH 2. 186 MEETING OF THE AMERICAN was launched on its second, 17-day mission. University of ASTRONOMICAL SOCIETY Pittsburgh faculty conducted two of ten NASA Guest Inves- The Department of Physics & Astronomy and Allegheny tigator programs. Schulte-Ladbeck and Hillier, with graduate Observatory co-hosted the 186th meeting of the American student Herald, used Astro’s HUT and WUPPE telescopes Astronomical Society. The meeting was held downtown at to obtain far-UV spectra and UV spectropolarimetry of Wolf- the Vista Hotel and Lawrence Convention Center, from June Rayet stars. Espey, Schulte-Ladbeck and graduate student 11 through 16. Programmatic highlights of the meeting were Birriel obtained observations of symbiotic binary systems a special session at the Pittsburgh Supercomputing Center with the same telescopes. held jointly with the meeting of the Division of Computa- Espey, Schulte-Ladbeck, and Herald provided real-time tional Physics of the American Physical Society ͑June5-9͒, mission support that was not unlike remote observing, at the two Open Houses at Allegheny Observatory, and a Public Payload Operations Control Center in Huntsville, Alabama. Lecture by W.L. Freedman from The Observatories of the They participated in several pre-mission training sessions Carnegie Institution of Washington hosted jointly with The during the reporting period, in order to become certified in Carnegie Science Center. Gatewood presented an invited talk their respective positions, and to become integrated into the on ‘‘Current and Future Astrometric Systems.’’ Hazard’s in- HUT ͑Espey͒ and WUPPE ͑Schulte-Ladbeck & Herald͒ vited lecture on ‘‘The Limits of the Universe’’ was cancelled science teams. 568 ANNUAL REPORT

Among the immediate publications of Astro-2 observa- 5. EXTRAGALACTIC ASTRONOMY tions were two IAU Circulars, and several abstracts at the D.A. Turnshek’s main research efforts continued to be in 186th meeting of the American Astronomical Society. Two the area of observational cosmology. At Pittsburgh he has letters for the HUT ApJL special issue to appear on Nov. 20, worked with several graduate and undergraduate students, 1995, detailing first results on the far-UV spectra of the and with Khersonsky, Rao, Briggs, Hazard, and Espey. Turn- Wolf-Rayet stars and symbiotic stars observed with HUT, shek’s work with undergraduate students has been supported were prepared over the summer. with the aid of a NSF grant sponsoring research experiences In their ApJL, Schulte-Ladbeck, Hillier & Herald present for undergraduates. a spectral atlas of Wolf-Rayet stars, the first of its kind com- One area of research involves the study of Broad Absorp- paring spectral features in the far-UV along the WN se- tion Line ͑BAL͒ QSOs, with particular emphasis on placing quence. An Astro-1 data set of a WC binary is also included constraints on unified models of QSOs and deriving con- illustrating one HUT far-UV spectrum of the WC subtype. straints on the covering factors, ionization structure, and The spectrum of the Wolf-Rayet binary HD 5980, which re- metal abundances of the QSO BAL region gas. Broad Ab- cently showed variability characteristic of a Luminous Blue sorption Line QSOs have been the subject of a number of Variable, was compared with the WN sequence of spectra. studies with, for example, optical telescopes, HST, ROSAT and IRAS, with the aim of investigating the properties of Espey, Schulte-Ladbeck et al. prepared an ApJL which BAL regions, including their chemical composition, the pos- includes a simultaneous, multi-spectral data set on the sym- sible presence of dust, levels of ionization, photoionization biotic nova RR Tel. RR Tel is demonstrated to display very effects within BAL clouds, covering factors, large-scale and strong lines of O VI in the far-UV, simultaneously with small-scale cloud geometries, models for anisotropic con- highly polarized, broad features in the optical spectral region tinuum and line emission, and radiative transfer effects in the just beyond H␣ . This confirms that the Raman-scattering NV line. Turnshek advised three graduate students with their process plays a role in the formation of symbiotic spectra. thesis research on QSOs. M. Kopko is continuing his thesis Schulte-Ladbeck and Birriel analyzed archival IUE spec- work on investigating chemical compositions and modeling tra of the symbiotic stars AG Peg and AG Dra, in support of ionization effects in BAL QSOs. L. Lee is continuing his Astro-2 observations. AG Peg, a symbiotic nova with Wolf- thesis work on studying correlations between the BALs and Rayet spectral features, was not actually observed during the broad emission lines, and is investigating the nature of the mission. Astro-2 data on AG Dra were secured, and the IUE NV broad emission line which has relevance to the chemical results will provide baseline physical conditions of the sys- evolution of QSOs and models for the BAL region. C. Sirola tem over the last few years. is continuing his thesis work on the study of geometry effects In support of the Astro-2 mission, Hillier conducted an pertaining to BAL QSOs, including an HST study of the observing run at the Anglo-Australian Telescope, gathering gravitationally lensed Cloverleaf BAL QSO and an analysis optical spectropolarimetry of several Wolf-Rayet stars in- of the optical variability properties of BAL and non-BAL cluding HD 5980, of symbiotic stars, and of the Luminous QSOs undertaken with the Swope 40-inch Telescope of the Blue Variable AG Car. Carnegie Observatories at Las Campanas, Chile. In addition, Schulte-Ladbeck and Herald, in collaboration with P. Ee- graduate student E. Monier, along with S. Rao and B. Espey, nens ͑Mexico͒ and P. Morris ͑Netherlands͒, have been using have collaborated on a number of these investigations. S. IUE, published optical, and new IR spectra of Wolf-Rayet Sherer and undergraduates P. Morris and D. Noll have as- stars for a systematic investigation into the wind structure sisted with these efforts. from the line width versus ionization potential relationship. Another area involves the study of ‘‘intervening’’ QSO This project is anticipated to provide insight into what drives absorption line systems in order to investigate problems in the winds of Wolf-Rayet stars, and it will also furnish new the areas of the gaseous extent of galaxies, galaxy formation, and the intergalactic medium. Turnshek is a member of the data on the continuum- and line-forming regions in the ex- HST QSO Absorption Line Key Project Team and this has tended atmospheres of these stars. Schulte-Ladbeck and Her- facilitated a number of different studies of the evolution of ald also re-investigated this relationship in the Planetary the properties of the various types of intervening QSO ab- Nebula Central Star HD 184738/BD ϩ30o3639, and pre- sorption line systems, including Lyman-alpha forest systems, sented a paper at the Ven conference ‘‘Planetary Nebulas metal line and Lyman limit systems, and damped Lyman- with Wolf-Rayet Type Nuclei’’ on the results. alpha systems. Work on the damped Lyman-alpha systems Schulte-Ladbeck collaborated with STScI colleagues A. with V. Khersonsky, S. Rao, and F. Briggs has proceeded in Nota and M. Clampin on various projects related to the study several new directions. In particular, Khersonsky and Turn- of the geometry and the mass-loss history of Luminous Blue shek have worked on interpreting the evolution of the Variables. The work recently culminated in the proposition damped systems in a way that is more closely tied to a star of a ‘‘unified picture’’ for the formation of the circumstellar formation scenario in the galaxy population as a whole rather nebulae, via wind-wind interactions, which is similar to that than link the damped systems to particular galaxy types. Rao, used to explain the shaping of Planetary Nebulae. Turnshek, and Briggs have developed a new and more effi- Hillier and Miller worked on several improvements of cient method to perform a UV survey for low-redshift Hillier’s non-LTE radiative transfer code for expanding at- damped systems. In addition, Khersonsky, Briggs, and Turn- mospheres. shek completed an investigation of simulated spectra in an UNIVERSITY OF PITTSBURGH 569 effort to more clearly understand the requirements for mea- Gatewood, G. and Kiewiet de Jonge, J. 1995, AJ, 450, 364, suring deuterium in QSO absorption line systems. Work has ‘‘MAP-Based Trigonometric Parallaxes of Altair and also begun with Khersonsky and S. Sherer to place con- Vega’’ straints on HI Gunn-Peterson at low redshift. Finally, Turn- Han, I. and Gatewood, G. 1995, PASP, 107, 399, ‘‘A Study shek began advising E. Monier on a thesis project aimed at of the Accuracy of Narrow Field Astrometry using Star placing constraints on QSO absorber size scales. This last Trails taken with the CFHT’’ work is also in collaboration with C. Hazard along with as- Herald, J.E., Schulte-Ladbeck, R.E., Eenens, P., Morris, P., sistance from undergraduate A. Landrum. 1995, BAAS, 27, 838, ‘‘Ionization Stratification in the Hazard’s work has focussed on surveys for Quasars; he is Winds of Wolf-Rayet Stars – A sample of the WN se- finalizing a new catalog of objects. quence’’ Hopp, U., Schulte-Ladbeck, R.E., 1995, A&AS, 111, 527, 6. EDUCATIONAL PROGRAMS ‘‘CCD Photometry of 11 Resolved Dwarf Irregular Gal- Allegheny Observatory continued to be used for student axies’’ education and public tours. The annual public open house Johnson, J.J., and the WUPPE team, 1995, IAU Circ. No. was attended by approximately 500 people. A high-school 6146, ‘‘Nova Aquilae 1995’’ workshop was conducted using Keeler-telescope CCD im- Johnson, J.J., et al., 1995, BAAS, 27, 837, ‘‘Ultraviolet ages of a field containing an RR Lyrae star. This was a con- Spectropolarimetry of Three Classical Novae in Outburst’’ tinuation of a NASA IDEA project awarded to Schulte- Khersonsky, V.K., Briggs, F.H., and Turnshek, D.A. 1995, in Ladbeck and Gatewood. D.A. Turnshek and D.E. Turnshek, The Light Element Abundances, ESO Astrophysics Sym- along with M. Anticole and S. Sherer, have continued to posium ͑Springer͒, ed. P. Crane, p. 89, ‘‘On the Measure- promote science and astronomy education at the elementary ment of the Deuterium to Hydrogen Ratio in QSO Ab- school level and to the public with the aid of a NASA IDEA sorption Line Systems’’ grant, using their new mobile solar observatory. Khersonsky, V.K., Briggs, F.H., and Turnshek, D.A., 1995, PASP, 107, 570, ‘‘On the Measurement of the Deuterium PUBLICATIONS to Hydrogen Ratio in QSO Absorption Line Systems’’ Anderson, C.M., et al., 1995, BAAS, 27, 836, ‘‘The Khersonsky, V.K., and Turnshek, D.A., 1995, in Extragalac- WUPPE/Astro-2 Galactic Interstellar Polarization Pro- tic Background Radiation, STScI Symposium Series gram’’ ͑Cambridge University Press͒, eds. D. Calzetti, M. Livio, Bergeron, J., Petitjean, P., Bahcall, J.N., Boksenberg, A., and P. Madau, p. 275, ‘‘On the Absorption of UV Radia- Hartig, G.F., Jannuzi, B.T., Kirhakos, S., Sargent, W.L.W., tion in Lyman-Alpha Clouds’’ Savage, B.D., Schneider, D.P., Turnshek, D.A., Weymann, Khersonsky, V.K., and Turnshek, D.A., 1995, in Extragalac- R.J., and Wolfe, A.M. 1994, ApJ, 436, 33, ‘‘The HST tic Background Radiation, STScI Symposium Series Quasar Absorption Line Key Project VI. Properties of the ͑Cambridge University Press͒, eds. D. Calzetti, M. Livio, Metal-Rich Systems’’ and P. Madau, p. 279, ‘‘On the Contribution of Star Form- Bjorkman, K.S., et al., 1995, BAAS, 27, 837, ‘‘First Look at ing Galaxies to the UV Background Radiation’’ New WUPPE/Astro-2 Observations of Hot Stars’’ Khersonsky, V.K., and Turnshek, D.A., 1995, ApJ, 442, 76, Clampin, M., Schulte-Ladbeck, R.E., Nota, A., Robberto, ‘‘On Observational Constraints on the Shapes of the Dark M., Paresce, F., Clayton, G.C., 1995, AJ, 110, 251, ‘‘The Matter Density and Temperature Distributions in the Circumstellar Environment of HR Carinae’’ Model of Dark Matter-Confined Lyman-alpha Clouds’’ Espey, B.R., Kriss, G.A., and the HUT team, Johnson, J.J., Khersonsky, V.K., and Turnshek, D.A., 1995, in QSO Ab- Schulte-Ladbeck, R.E., and the WUPPE team, 1995, sorption Lines, ESO Astrophysics Symposia ͑Springer͒, IAU Circ. No. 6148, ‘‘CH Cygni’’ ed. G. Meylan, p. 39, ‘‘The Mass Spectrum of Giant Hy- Espey, B.R., Schulte-Ladbeck, R.E., Kriss, G.A., Hamann drogen Clouds Associated with Damped Lyman-Alpha III, F.W., Johnson, J.J., Schmidt, H.M., 1995, BAAS, 27, Absorbers’’ 854, ‘‘Observations of Symbiotic Stars with the Astro-2 Khersonsky, V.K., and Turnshek, D.A., 1995, in QSO Ab- Mission’’ sorption Lines, ESO Astrophysics Symposia ͑Springer͒, Gatewood, G., 1994, PASP, 106, 138, ‘‘One Milliarcsecond ed. G. Meylan, p. 351 ‘‘The Observed Properties of Precision Studies in the Regions of the Binary Stars k Lyman-Alpha Clouds as Signatures of Dark Matter Poten- Equulei and 1 Orionis’’ tial Wells’’ Gatewood, G. and Kiewiet de Jonge, J. 1994, AJ, 428, 166, Kopko, M., Turnshek, D.A., and Espey, B.R. 1994, in IAU ‘‘MAP Based Trigonometric Parallaxes of Open Clusters: Symposium 159: Quasars Across the Electromagnetic The Praesepe’’ Spectrum ͑Kluwer͒, eds. T.J.-L. Courvoisier and A. Gatewood, G. 1995, A&SS, 223, 91, ‘‘A Study of the Astro- Blecha, p. 111, ‘‘Optical, HST, and ROSAT Observations metric Motion of Barnard’s Star’’ of BAL QSOs’’ Gatewood, G., Kiewiet de Jonge, J. and Heintz, W.D. 1995, Lanzetta, K.M., Wolfe, A.M., and Turnshek, D.A., 1995, AJ, 109, 434, ‘‘Astrometric Studies in the Region of Al- ApJ, 440, 435, ‘‘The IUE Survey for Damped Ly␣ and gol’’ Lyman-Limit Absorption Systems: Evolution of the Gas- Gatewood, G. 1995, AJ, 445, 712, ‘‘MAP Based Trigonomet- eous Content of the Universe’’ ric Parallaxes of Open Clusters: Coma Berenices’’ Lee, L., Turnshek, D.A., and Sherer, S., 1995, BAAS, 27, 570 ANNUAL REPORT

846, ‘‘On the Origin of the NV Broad Emission Line in gent, W.L.W., Bahcall, J.N., Bergeron, J., Hartig, G.F., QSO Spectra’’ Jannuzi, B.T., Kirhakos, S., Savage, B.D., Schneider, D.P., Massa, D., et al., 1995, ApJL, 452, 53, ‘‘The IUE MEGA Turnshek, D.A., and Weymann, R.J., 1995, 444, 64, ‘‘The Campaign. I. Wind Variability and Rotation in Early-Type HST Quasar Absorption Line Key Project V. Redshift Stars’’ Evolution of Lyman Limit Absorption in the Spectra of a Monier, E., Turnshek, D.A., Lupie, O.L, 1995, BAAS, 27, Large Sample of QSOs’’ 852, ‘‘Constraints on Lyman-Alpha Forest Cloud and Storrie -Lombardi, L.J., McMahon, R.G., Irwin, M.J., and Metal-Line Cloud Sizes and Shapes from HST-FOS Spec- Hazard, C., 1995, in QSO Absorption Lines, ESO Astro- tra of the Gravitationally Lensed QSO H1413ϩ1143’’ physics Symposia ͑Springer͒, ed. G. Meylan, p. 47, ‘‘High Nordsieck, K.H., et al., 1995, BAAS, 27, 837, ‘‘Ultraviolet/ Redshift Lyman Limit and Damped Lyman-Alpha Ab- Visible Spectropolarimetry of Interacting Binaries by sorbers’’ WUPPE and Wisconsin Pine Bluff Observatory’’ Storrie -Lombardi, L.J., McMahon, R.G., Irwin, M.J., and Nota, A., Livio, M., Clampinn, M., Schulte-Ladbeck, R.E., Hazard, C., 1995, ApJ, 427, L13, ‘‘Evolution of the Ly- 1995, ApJ, 448, 778, ‘‘Luminous Blue Variables: A Uni- man Limit Systems Over the Redshift Range 0.40 to fied Picture’’ 4.69’’ Rao, S.M., Turnshek, D.A., and Briggs, F.H. 1995, ApJ, 449, Turnshek, D.A., 1995, BAAS, 27, 872, ‘‘BAL QSOs and 488, ‘‘The Incidence of Damped Lyman-alpha Systems in Constraints on BAL Gas Abundances’’ the Redshift Interval 0 to 4’’ Turnshek, D.A. 1995, in The Light Element Abundances, Rao, S., Turnshek, D.A., and Briggs, F.H., 1995, in QSO ESO Astrophysics Symposium ͑Springer͒, ed. P. Crane, p. Absorption Lines, ESO Astrophysics Symposia 93, ‘‘Studies of the Cloud Structure, Ionization Structure, ͑Springer͒, ed. G. Meylan, p. 43, ‘‘A Damped Lyman- and Elemental Abundances in High Redshift QSO BAL Alpha Survey at Redshift Less Than 1.65’’ Region Gas’’ Schulte -Ladbeck, R.E., 1995, Ap&SS, 221, 347, ‘‘Spec- Turnshek, D.A., 1995, in QSO Absorption Lines, ESO As- tropolarimetry of luminous, hot stars’’ trophysics Symposia ͑Springer͒, ed. G. Meylan, p. 223, Schulte -Ladbeck, R.E., Vaidya, A., 1995, in ‘‘Circumstellar ‘‘The Covering Factors, Ionization Structure, and Chemi- dust disks and planet formation, 10th IAP meeting, eds. R. cal Composition of QSO BAL Region Gas’’ Ferlet and A. Vidal-Madjar, Edition Frontieres, p. 387, Vaidya, A., Schulte-Ladbeck, R.E., 1995, BAAS, 27, 825, ‘‘Spectropolarimetry of a few Herbig Ae/Be stars and can- ‘‘Conclusions about disk geometries in a few Herbig didates’’ Ae/Be stars’’ Schulte -Ladbeck, R.E., Hillier, D.J., Herald, J.E., 1995, Williger, G.M., Baldwin, J.A., Carswell, R.F., Cooke, A.J., BAAS, 27, 838, ‘‘Astro-2 Observations of Wolf-Rayet Hazard, C., Irwin, M.J., McMahon, R.G., and Storrie- stars’’ Lombardi, L.J., 1994, ApJ, 428, 574, ‘‘Lyman Alpha Ab- Sirola, C., Turnshek, D.A., Monier, E., Sheaffer, S., Wey- mann, R.J., Morris, S., Duhalde, O., Krzeminski, W., sorption in the Spectrum of the zϭ4.5 QSO BR 1033- Kunkel, W., and Roth, M., 1995, BAAS, 27, 845, ‘‘Re- 0327’’ sults from the Las Campanas Program to Monitor QSO Wolff, M.J., et al., 1995, BAAS, 27, 837, ‘‘The First Ultra- Optical Brightness Variation’’ violet Linear Spectropolarimetry of Mars’’ Stengler -Larrea, E.A., Boksenberg, A., Steidel, C.C., Sar- Regina E. Schulte-Ladbeck