College of Mathematical & Physical Sciences
Department of Astronomy
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The Ohio State University College of Mathematical & Physical Sciences Department of Astronomy |
Our graduate program offers a variety of specializations in observational and theoretical astronomy as well as in astronomical instrumentation. This brochure will give you some of the details of our program. We hope it gives you the information you are looking for as you make the choice of which graduate programs to apply to. We encourage you to make arrangements to visit us and see firsthand our department and facilities, and to meet the people who could be a part of your career in astronomy.
In our graduate program, your first two years consist primarily of course work that includes core-course sequences which are offered in alternate years. In addition to taking lecture courses in astronomy and physics, you will also participate in advanced seminars on topics of current interest and in directed research projects.
During spring quarter of your first year, your progress in the program will be reviewed by the entire graduate faculty of the department. If you successfully pass this review, you will be advised to (a) bypass the master's degree and proceed directly toward the Ph.D.; (2) obtain a master's degree as an intermediate step towards the Ph.D.; or (3) consider pursuing the master's as a terminal degree.
You will be expected to have developed strong, well-defined research interests by the beginning of your third year of study, at which time you will likely take your General Examination for admission to candidacy for the Ph.D.
Our primary observational research instrument is the 1.8-meter Perkins Reflector, operated in collaboration with the Ohio Wesleyan University and the Lowell Observatory. It is located at a dark-sky site on Anderson Mesa about 15 kilometers southeast of Flagstaff, Arizona, where it was moved in 1961 from its original home at the Perkins Observatory in Delaware, Ohio just north of Columbus. Faculty, postdocs, and graduate students at Ohio State receive one-half of the available observing time. The telescope is operated under full computer control, and equipped with modern, state-of-the-art instruments designed and built by our Astronomical Instrumentation Facility. These include a low- to moderate-resolution CCD spectrometer, a CCD focal reducing camera for both direct imaging and Fabry-Perot spectroscopy, and a near-infrared array imaging spectrometer. These instruments are being used for studies of galactic structure, active galactic nuclei and QSOs, gaseous nebulae, interacting binary stars, the structure and dynamics of external galaxies, and stellar evolution.
Our Flagstaff operation employs a full-time research astronomer and a professional observing assistant to support day-to-day observatory operations and to assist astronomers at the telescope. A few of our graduate students have spent the summer in Flagstaff working on research projects with the Arizona research staff. There are also collaborations going on with astronomers at the Lowell Observatory engaged in a variety of extragalactic and planetary research programs.
In addition to the Arizona facility, the department maintains the 0.8-meter Schottland Reflector in the old Perkins Telescope dome at the Perkins Observatory near Delaware, Ohio. Operated jointly with the Ohio Wesleyan University, this telescope is primarily used for teaching and public observing programs, and has recently been equipped with a computerized drive system and a CCD focal reducing camera. Graduate students have an opportunity to take part in the public education programs offered at Perkins.
The departmental computing facilities at Ohio State are among the best in the nation for astronomical research, especially for a department of our size. Our graduate students have wide access to resources that include an extensive, fully integrated network of more than 40 Sun, DEC, and SGI workstations (many of which are located in graduate student offices), and a recently acquired Silicon Graphics Challenge-series graphics supercomputer. These are used by faculty and students for a wide variety of theoretical research programs, and for the reduction and analysis of observational data. Many of our graduate students also work with the nearby Ohio Supercomputing Center's Cray YMP and T3D massively-parallel supercomputers for their theoretical research, which combined with the Ohio Supercomputing Center's state-of-the-art scientific visualization laboratory provides a rare and powerful resource for large-scale computational astrophysics.
The main collection of astronomical literature is housed in the new Science and Engineering Library. This comprises more than 14,000 books, journals, and observatory publications covering all areas of astrophysics. A smaller collection of books and principal journals is maintained in our department reading room. Students also have access to the extensive library holdings of the Ohio State University.
The Astronomical Instrumentation Facility (AIF) operates machine and electronics shops, and optical, mechanical, and electronic design facilities. Software support for instrumentation is also undertaken by the AIF. The close integration of the AIF staff and department faculty helps to provide some of our graduate students hands-on experience with modern instrumentation.
Several faculty members are engaged in studies of the physical properties of stars and the stellar content of galaxies, both of which are basic to our understanding of the fundamental evolutionary processes in the Universe. Other faculty members are pursuing observations of the interstellar medium. A strong emphasis is placed on infrared and optical observations, both spectroscopic and imaging studies, on our own 1.8-m telescope, and on larger telescopes around the world.
Another group of observers are studying the physics of active galactic nuclei, both nearby Seyfert galaxies and more distant quasars. These observations are made across the Electromagnetic spectrum, with emphasis on ground-based observations obtained with the 1.8-m telescope and at the National Optical Astronomy Observatories, and on ultraviolet observations obtained with the International Ultraviolet Explorer and the Hubble Space Telescope.
We also have a strong program in theoretical astrophysics. A theoretical astrophysics group, consisting of members of both the astronomy and physics departments, concentrates on studies of the astrophysics of the early Universe, the development of large-scale structure, and dark matter. We also have active programs in computational atomic and molecular astrophysics, in collaboration with the Ohio State chemistry and physics departments, and in the theory of stellar structure and evolution.
Our Astronomical Instrumentation Facility (AIF) is one of the few such groups in the U.S. Its members are astronomers, engineers, and technicians dedicated to the design and construction of state-of-the-art instruments for ground-based telescopes. The AIF is engaged in detector development (infrared arrays and CCDs), advanced optical design, and mechanical and systems design. Our flagship instruments are the Imaging Fabry-Perot Spectrometer (IFPS) and the Ohio State InfraRed Imaging Spectrometer (OSIRIS), and future projects include developing instruments for the next generation of large telescopes (Gemini, Magellan, and the Large Binocular Telescope).
University fellowships, which are awarded on a competitive basis by the University on nomination by the department, carry no formal duties, and fellows are expected to devote full time to graduate study. Fellows are expected to register for 12 to 16 credit hours per academic quarter. Particularly promising entering students may also be offered multiple-year financial packages including teaching and research assignments structured so as to rapidly advance them towards research careers.
Outstanding graduate students in their final year of dissertation work are nominated by the department for Ohio State Presidential Fellowships, which allow students to work full time on their dissertation research.
Graduate teaching and research associates normally receive half-time appointments. These appointments require a maximum of 20 hours of duty per week during the academic quarter. Teaching associates usually assist in teaching the department's survey courses, Astronomy 161 - 162. Their duties typically involve assisting in the preparation and grading of exams, tutoring students, conducting planetarium and telescope demonstrations, and occasional lecturing. The course load for graduate associates usually ranges from 7 to 12 credit hours per quarter.
The city has what you expect from a major metropolitan area - a thriving downtown complete with excellent restaurants, a symphony orchestra, a ballet company, theaters, museums, and art galleries. The metropolitan park system, in place for over 100 years, features many bike paths and jogging trails. Two rivers and major reservoirs offer Columbus residents areas for boating, sailing, canoeing, water skiing, and fishing. A fine zoo, dozens of shopping malls, specialty shops, and housing styles, ranging from turn-of-the-century brownstones to ultramodern condominiums, and many fine public and private schools have made Columbus an attractive place to work, get an education, start a business, begin a career, or raise a family.
If you are married you will discover that the local economy offers a range of employment opportunities for your spouse. And unlike many cities in the Northeast and Midwest, Columbus has a relatively low unemployment rate.
The university also maintains student housing for families in Buckeye Village, an apartment complex on the campus. Buckeye Village provides a congenial environment and is close to shopping and other facilities. Each apartment is equipped with major kitchen appliances. Two-bedroom apartments are available to families with children.
For additional information on housing, please write to
Contracts and Assignments
The Ohio State University
640 Lincoln Tower, 1800 Cannon Drive
Columbus, OH 43210-1230
Tel: +1 614 292 8266
Ample off-campus housing of all types is available at reasonable rates. For additional information, you can write to
The Office of Commuter Student Affairs
The Ohio State University
211 Ohio Union, 1739 North High Street
Columbus, OH 43210-1392
Tel: +1 614 292 0100
Ohio State's physical recreation and sports complexes are among the finest in the world. Here, you'll find facilities for tennis, basketball, softball, soccer, volleyball, squash, racquetball, handball, golf, crew and sailing, and swimming and diving. We also have indoor jogging tracks, two completely equipped conditioning rooms, and a Nautilus room. In addition, the University offers intramural programs for almost any sport you can imagine.
To be admitted to our program you are required to have advanced undergraduate preparation in physics (classical mechanics, electricity and magnetism, thermodynamics and statistical mechanics, and quantum mechanics) as usually required for an undergraduate degree with a major in physics or astronomy.
To apply you must submit official Graduate Record Examination (GRE) aptitude scores and GRE Advanced Physics scores.
To be considered for our program, please submit to our department the following materials:
Mail application Materials:
Graduate Committee Chair
Department of Astronomy
The Ohio State University
174 West 18th Avenue
Columbus, OH 43210-1106
USA
Applications must also include:
The Astronomical Instrumentation Facility (AIF) of the Department of Astronomy is dedicated to the design and construction of state-of-the-art instruments for optical and infrared astronomy. With a full-time staff of 12 professionals the AIF has developed a permanent infrastructure to facilitate the construction of world-class analog and digital electronics, optics, mechanisms, and instrument structures, as well as cryogenic and vacuum systems. Graduate students are always welcome to participate in AIF projects. The department, including the AIF, is structured, both from an architectural and an organizational standpoint, to insure close and productive interaction between the instrument users and builders.
In addition to supervising the AIF's two major instruments (the Imaging Fabry-Perot Spectrometer and the Ohio State InfraRed Imaging Spectrometer) from conception to commissioning, I have developed flexible instrument and detector electronics systems and investigated coating systems for large astronomical mirrors and very high performance anti-reflection coating for transmissive optics. Current projects include the final pre-construction activities for a new 800 sq-m home for the AIF, a 2048x2048 CCD camera for Lowell Observatory and preparation of a proposal to the Gemini 8-m telescope project for the construction of their IR spectrometer.
Atwood, B.; Byard, P.; O'Brien, T.; DePoy, D.; and Frogel, J. 1993. OSIRIS. Proceedings of ESO Conference on Progress in Telescope and Instrumentation Technologies.
Atwood, B. and Sabol, B. 1993. Studies of Some Aspects of Aluminizing Large Astronomical Mirrors. Proceedings of ESO Conference on Progress in Telescope and Instrumentation Technologies.
Atwood, B.; Henden, A. A.; Truax, R. J.; and Byard, P. L. 1992. The Ohio State Detector/Instrument Electronics System. Photoelectronic Image Devices 1991 (Proceedings of 10th Symposium on Photoelectronic Image Devices), ed. B. L. Morgan, Institute of Physics Conference Ser. 121, 131.
Pogge, R.W.; Owen, J.M.; and Atwood, B. 1992. Imaging Spectrophotometry of the Orion Nebula Core. I. Emission-Line Mapping and Physical Conditions. Astrophysical Journal 399:147-158.
My group's research involves studies of various astrophysical environments via both experimental and theoretical studies of the nucleosynthesis produced therein. Our subjects include big bang nucleosynthesis, stellar nucleosynthesis, and other astrophysical sites such as active galactic nuclei. One specific example involves reactions on short lived nuclei, most notably Li-8, that are important for predicting the abundances of nuclides produced in the big bang. Reactions that both destroy Li-8, and convert it to heavier nuclides, have been studied. Another study has focussed on the p-process nuclides, the most proton rich nuclides in the periodic table. Since their synthesis occurs in very high temperature environments, their understanding involves highly unstable nuclides. The most anomalous p-process nuclides are the lightest molybdenum isotopes; a recent combined theoretical-experimental effort has pointed out a possible site for their production, and produced several tests of the theory. Most of our experimental work utilizes radioactive beams, a recently developed type of research capability.
Boyd, R. N. 1994. Physics with Radioactive Nuclear Beams. International Journal of Modern Physics E3, in press.
Balbes, M. J.; Boyd, R. N.; and Mathews, G. J. 1993. The Primordial Helium Abundance as Determined from Chemical Evolution of Irregular Galaxies. Astrophysical Journal 418:229
Balbes, M. J., et al. 1993. 2H Induced Reactions on 8Li and Primordial Nucleosynthesis. Physics Review Letters 71:3931.
Boyd, R. N., et al. 1992. Measurement of the 8Li(a,n)11B Reaction Cross Section at Energies of Astrophysical Interest. Physics Review Letters 68:1283.
Boyd, R. N. and Fencl, H. 1991. Photoerosion and the Abundances of 7Li, 9Be, 10B, and 11B in Active Galactic Nuclei. Astrophysical Journal 373:84.
My main research interests involve infrared studies of emission line regions, the Galactic Center, and young stars. In particular, we have detected and identified new spectral features in the near infrared spectra of many such sources that allow us to examine regions difficult to access using traditional optical techniques. These studies have been driven by the enormous gains in the capabilities of infrared instrumentation and I actively participate in the development of these instruments.
DePoy, D. L. and Pogge, R. W. 1994. Spectrophotometry of the Orion Nebula and the Detection of Significant [FeII] Emission. Astrophysical Journal, in press.
DePoy, D. L. and Shields, J. C. 1994. The HeI 2.06-micron to Br-gamma Ratio in 12 Planetary Nebulae. Astrophysical Journal 422:187.
DePoy, D. L.; Terndrup, D. M.; Frogel, J. A.; Atwood, B.; and Blum, R. 1993. Baade's Window at 2.2-micron: The Luminosity Function and a Comparison with the Bulge of M31. Astronomical Journal 105:2121.
DePoy, D. L. 1992. Detection of [FeII] Emission in the Galactic Center. Astrophysical Journal 398:512.
DePoy, D. L.; Lada, E. A.; Gatley, I.; and Probst, R. 1990. The Luminosity Function in NGC 2023. Astrophysical Journal 356:L55.
My current interests are stellar and galactic evolution and stellar synthesis models of galaxies. I try to develop new techniques, based primarily on infrared observations of stars, clusters, and galaxies, that can help to explore these areas of interest. Current projects, most of which involve the collaboration of graduate students and post doctoral fellows include (1) the stellar content and chemical composition of the Galactic bulge; (2) Cool giants as a probe of the evolutionary history of the LMC and SMC; (3) Infrared arrays applied to the study of Globular clusters. Finally, I am leading a major departmental effort of assembling and analyzing digital optical and infrared images of about 300 spiral galaxies.
Vader, J. P.; Frogel, J.A.; Terndrup, D.M.; and Heisler, C.A. 1993. Galaxies with Spectral Energy Distributions Peaking near 60-micron. I. Optical Spectroscopy, Infrared Photometry, and Radio Continuum Data. Astronomical Journal. 106:1743.
Houdashelt, M.L.; Frogel, J.A.; and Cohen, J.G. 1992. Giants in Old Open Clusters: Temperatures, Luminosities, and Abundances from Infrared Photometry. Astronomical Journal 103:163.
Davies, R. L.; Frogel, J. A.; and Terndrup, D. M. 1991. The Stellar Luminosity Function in the Bulge of M31. Astronomical Journal 102:1729.
Frogel, J.A.; Mould, J.; and Blanco, V. M. 1990. The Asymptotic Giant Branch of Magellanic Cloud Clusters. Astrophysical Journal 352:96.
Frogel, J. A.; Terndrup, D.M; Blanco, V. M.; and Whitford, A. E. 1990. Galactic Bulge M Giants. II. Content and Structure of the Bulge Between b = -3 and -12. Astrophysical Journal 353:494.
My primary interest is to identify the nature of the dark matter which makes up 90-99% of the mass of the universe. Recently, I have focused in particular on understanding the MACHOs (compact dark objects). Recent experiments seem to show that these make up only a small fraction of the dark matter, but are comparable in mass to the known luminous matter. I am also interested in using star counts to map the structure of the Milky Way galaxy, and I have a number of the interests including the cosmological distance scale, weak gravitational lensing, and statistical methods in astronomy.
Gould, A. and Villumsen, J. 1994. Weak Lensing By Nearby Structures. Astrophysical Journal Letters 428:L45-L48.
Gould, A. 1994. The Metallicity Dependence of Inferred Cepheid Distances. Astrophysical Journal 426:542-552.
Maoz, D. and Gould, A. 1994. A Spectroscopic Method To Find Macho Proper Motions. Astrophysical Journal Letters 425:L67.
Gould, A. 1994. Macho Velocities From Satellite-Based Parallaxes. Astrophysical Journal Letters 421:L75.
Gould, A.; Bahcall, John N.; and Maoz, D. 1993. Star Counts from the HST Snapshot Survey I: Galactic Models. Astrophysical Journal Supplement 88:53.
Our research group studies the formation of molecules in both interstellar and circumstellar sources. The observation of molecules by radio, infrared, and optical astronomers yields detailed information about physical conditions in various sources if one understands the details of molecular formation. We have developed chemical models for an assortment of sources that yield predictions for molecular abundances. We are particularly interested in giant molecular clouds, since these objects are the sites of star formation. Carbon-rich circumstellar envelopes surrounding AGB stars constitute another type of interesting source. In both giant molecular clouds and carbon-rich circumstellar envelopes, large abundances of organic molecules are produced.
Herbst, E.; Lee, H.-H.; Howe, D. A.; and Millar, T. J. 1994. The Effect of Rapid Neutral-neutral Reactions on Chemical Models of Dense Interstellar Clouds. M.N.R.A.S 268:335.
Caselli, P.; Hasegawa, T. I.; and Herbst, E. 1994. The Production of Condensed Phase CO in Quiescent Molecular Clouds. Astrophysical Journal 421:206.
Hasegawa, T. I., and Herbst, E. 1993. Three-phase Chemical Models of Dense Interstellar Clouds: Gas, Dust Particle Mantles and Dust Particle Surfaces. M.N.R.A.S. 263:589.
Caselli, P.; Hasegawa, T. I.; and Herbst, E. 1993. Chemical Differentiation Between Star-Forming Regions: The Orion Hot Core and Compact Ridge. Astrophysical Journal 408:548.
My research interests have been primarily in laboratory spectroscopy, especially in the phenomena of autoionization and inner-shell excitation, and in the unusual binary SS 433. I have been particularly interested in the 6-day variation of SS 433 that appears in the radial-velocity data. In recent years I have had little time for research, however, serving as an Acting Assistant Dean, Acting Chair, and now Vice Chair of the Department of Astronomy.
Collins, G. W., II, and Newsom, G. H. 1988. Transient and Secular Variations of the Moving-Line Spectra from SS 433. Astrophysical Journal 331:486-493.
Newsom, G. H., and Collins, G. W., II. 1986. Period and Cone-Angle Changes in SS 433. Astronomical Journal 91:118-124.
Pitts, R. E. and Newsom, G. H. 1986. Shock Tube Measurements of Y I and Y II Oscillator Strengths. Journal of Quantitative Spectroscopy and Radiative Transfer 35:383-399.
Collins, G. W., II, and Newsom, G. H. 1986. A Dynamical Model for SS 433. Astrophysical Journal 308:144-151.
Newsom, G. H. and Collins, G. W., II. 1981. Short-Period Variations in the Moving Line Spectrum of SS 433. Astronomical Journal 86:1250-1258.
My main research interest concerns the evolution and nature of quasars. For many years, I have been involved in surveys for quasars at high redshifts using both the slitless spectrum technique and multicolor imaging. The resulting samples of objects have yielded valuable information on both the evolution of the luminosity function of quasars and their 3-dimensional distribution in space. My collaborators and I have found evidence for the space density of quasars to reach a maximum at a redshift near 3.3, when the universe was a tenth its current age, and to decline steeply at higher redshifts. At the same time we have used spectroscopic data from the survey projects to study the nature of the emission-line regions in quasars, which will yield improved information about the physical conditions and chemical composition of the gas in the central regions of quasars. Present and future research will include deep surveys for quasars (which will also yield valuable information on faint galaxies and on stars in the galactic halo); continuing spectroscopic studies; and infrared observations that will bear on the possible presence of dust absorption at high redshift and on the chemical evolution of quasars.
Osmer, P. S.; Porter, A. C.; and Green, R. L. 1994. Luminosity Effects and the Emission-Line Properties of Quasars with 0 < Z < 3.8. Astrophysical Journal, in press.
Warren, S. J.; Hewett, P. C.; and Osmer, P. S. 1994. A Wide-Field Multicolor Survey for High-Redshift Quasars, Z > 2.2, III. The Luminosity Function. Astrophysical Journal 421:412.
Osmer, P. S. 1993. Gemini Science Requirements, Version 1.1. Gemini Project Document. SPE-PS-60001.
My research is directed towards determination of the physical nature of active galactic nuclei (AGNs). These are the most luminous discrete sources in the Universe, as bright as an entire giant galaxy of normal stars, but are nevertheless very compact, only about the size of the Solar System. The immediate goal of most of my recent research has been to probe the inner structure of AGNs on the smallest possible scales by the process of "reverberation mapping." The diffuse gas within several light days of the AGN continuum source responds to changes in the source brightness with a time delay that is attributable to light-travel time between the continuum source and the gas. By carefully monitoring changes in the continuum and the subsequent changes in the emission lines that arise in the diffuse gas, it is possible to determine the distribution, kinematics, and physical properties of the gas, and thus derive important characteristics of the central source (which is thought to be a 10 Million solar-mass black hole that is accreting mass and converting potential energy into radiation). The 1.8-m Perkins Telescope is used one night per week to obtain optical spectra of AGNs for this program. Much of this work involves large-scale international collaboration, including space-based observations with Hubble Space Telescope, the International Ultraviolet Explorer, and other satellites.
Peterson, B.M. 1994. An Overview of Reverberation Mapping: Progress and Problems. In Reverberation Mapping of the Broad-Line Region in Active Galactic Nuclei, eds. P.M. Gondhalekar, K. Horne, and B.M. Peterson, Astronomical Society of the Pacific Conference Series, in press.
Peterson, B.M., et al. (43 authors). 1994. Steps Toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. VII. Variability of the Optical Spectrum of NGC 5548 Over Four Years. Astrophysical Journal 425:622-634.
Peterson, B.M., and Korista, K.T. 1994. Intensive Spectroscopic Monitoring of NGC 5548 with HST and IUE. In Multi-Wavelength Continuum Emission of AGN, ed. T.J.-L. Courvoisier and A. Blecha, Kluwer Academic Pub., pp. 177-180.
Peterson, B.M.; Ali, B.; Horne K.; Bertram, R.; Lame, N.J.; Pogge, R.W.; and Wagner, R.M. 1993. The Structure of the Broad-Line Region in the Seyfert Galaxy Markarian 590. Astrophysical Journal 402:469-478.
Peterson, B.M. 1993. Reverberation Mapping of Active Galactic Nuclei. Publications of the Astronomical Society of the Pacific 105:247-268.
My research concentrates on stellar structure and evolution; because many areas of astronomy are influenced by stellar evolution theory, this has led me to investigate a range of subjects. I am particularly interested in physical processes, such as microscopic diffusion and mixing induced by stellar rotation, which are neglected in standard stellar models and can strongly alter some of the predictions of stellar evolution theory. Current research interests include solar models and the solar neutrino problem; stellar populations; cosmology (big bang nucleosynthesis, ages of globular clusters); angular momentum evolution in stars; and mixing in red giant branch stars.
Bailyn, C.D., and Pinsonneault, M.H. 1994. On the Luminosity Function, Lifetimes, and Origin of Blue Stragglers in Globular Clusters. Astrophysical Journal, in press.
Deliyannis, C.P.; Pinsonneault, M.H.; and Duncan, D.K. 1993. Evidence for a Dispersion in the Lithium Abundances of Extreme Halo Stars. Astrophysical Journal 414:740.
Bahcall, J.N., and Pinsonneault, M.H. 1992. Standard Solar Models, With and Without Helium Diffusion, and the Solar Neutrino Problem. Review of Modern Physics 64:885.
Horch, E.; Demarque, P.; and Pinsonneault, M.H. 1992. The Evolution of High-Metallicity Horizontal-Branch Stars and the Origin of the Ultraviolet Light in Elliptical Galaxies. Astrophysical Journal Letters 388:L53.
Pinsonneault, M.H.; Deliyannis, C.P.; and Demarque, P. 1992. Evolutionary Models of Halo Stars With Rotation: II Effects of Metallicity on Lithium Depletion, and Possible Implications for the Primordial Lithium Abundance. Astrophysical Journal Supplement 78:179.
Pinsonneault, M.H.; Kawaler, S.D.; and Demarque, P. 1990. Rotation of Low Mass Stars: A New Probe of Stellar Evolution. Astrophysical Journal Supplement 74:501.
My research interests are primarily concerned with the astrophysics of gaseous nebulae in a variety of environments from regions surrounding active galactic nuclei to nearby low-luminosity HII regions. I have studied how an active galactic nucleus interacts with its host galaxy environment, star formation activity in galaxies ranging from nearly quiescent S0 galaxies to nuclear starburst galaxies, and mapped the structure and ionization properties of Galactic gaseous nebulae at optical and near-infrared wavelengths. In the course of this work, I have developed a number of techniques for doing quantitative imaging spectrophotometry, by merging traditional long-slit spectroscopy, narrowband filter imaging at visual and near-infrared wavelengths, and imaging Fabry-Perot spectroscopy into a general toolkit for studying nebulae in both spatial and spectral detail. I have a long-standing interest in developing instrumentation for imaging and spectroscopy, and helped to build the Imaging Fabry-Perot Spectrometer (IFPS) for use on the 1.8-meter telescope in Flagstaff. My students, colleagues, and I have used the IFPS to study a wide variety of objects including planetary nebulae, Herbig-Haro objects, supernova remnants, active galaxies, interacting galaxies, and normal galaxies. I have also been participating in the Ohio State's Galaxy Imaging Survey and the International AGN Watch consortium.
DePoy, D.L., and Pogge, R.W. 1994. 2-micron Spectrophotometry of the Orion Nebula and the Detection of Significant [Fe III] Emission. Astrophysical Journal 433:1.
Lame, N.J., and Pogge, R.W. 1994. Imaging Spectrophotometry of the Planetary Nebula NGC 6720 (The Ring Nebula). Astronomical Journal 108:1860
Pogge, R.W., and DeRobertis, M.M. 1993. Extended Near-UV Continuum Emission and the Nature of the Polarized Broad Line Seyfert 2s. Astrophysical Journal 404:563.
Pogge, R.W., and Eskridge, P.B. 1993. Star Formation in the Disks of HI Rich S0 Galaxies. Astronomical Journal 106:1405.
Pogge, R.W.; Owen, J.M.; and Atwood, B. 1992. Imaging Spectrophotometry of the Orion Nebula Core. I. Emission-Line Mapping and Physical Conditions. Astrophysical Journal 399:147.
Pogge, R.W. 1992. Extended Object Spectrophotometry. In Astronomical CCD Observing and Reduction Techniques, ed. S. Howell, ASP Conference Series 23:195.
My research entails theoretical investigations devoted to the application of atomic physics to astronomy, with emphasis on the analysis of spectra from various astrophysical sources such as nebulae, supernovae, active galactic nuclei and stars, at all wavelengths ranging from far infrared to hard X-ray. The work involves large-scale quantum mechanical computations on sequential and massively parallel supercomputers for collisional and radiative atomic processes. Another aspect of the research is application to plasma physics in laboratory devices such as ion accelerators and tokamak fusion reactors. Several international collaborations are part of the program.
Zhang, H.L., and Pradhan, A.K. 1994. Atomic Data for the Iron Project. VI. Collision Strengths and Rate Coefficients for Fe II. Astronomy and Astrophysics, in press.
Peng, J., and Pradhan, A.K. 1994. Laser Action in Far-Infrared Astrophysical Sources. Astrophysical Journal Letters, in press.
Bautista, M.; Pradhan, A.K.; and Osterbrock, D.E. 1994. [Fe II] Emission from High Density Condensations in the Orion Nebula. Astrophysical Journal Letters, in press.
Bautista, M.; DePoy, D. L.; Pradhan, A.K.; Elias, J.H.; Gregory, B.; Phillips, M. M.; and Suntzeff, N.B. 1994. Near Infrared Spectra of SN 1987A: Days 936 to 1445. Astrophysical Journal., in press.
Seaton, M.J.; Yu, Y.; Mihalas, D.; and Pradhan, A.K. 1994. Opacities for Stellar Envelopes. M. N. R. A. S. 66:805-828.
Nahar, S. N., and Pradhan, A. K. 1994. Unified Treatment For Electron-Ion Recombination in the Close Coupling Approximation. Physical Review A 49:1816-1835.
I am interested in the internal structure of galaxies and other stellar systems, and in the large scale structure of the universe. My research projects are mainly theoretical, though I have used the 1.8m telescope at Flagstaff on occasion. In studying the structure of galaxies, I specialize in measuring the properties of galaxies as projected onto the plane of the sky and using these properties to deduce the intrinsic three-dimensional properties of the galaxies. In studying the large scale structure of the universe, I have measured statistical properties of the distribution of galaxies in space (the size and shape of voids, for instance). These properties can be used both to place constraints on models for structure formation and to make estimates of cosmological parameters.
Han, C. and Ryden, B. S. 1994. A Comparison of the Intrinsic Shapes of Globular Clusters in Four Different Galaxies. Astrophysical Journal 433:80-86.
Ryden, B. S. 1994. Self-similar Expansion of Axisymmetric Voids. Astrophysical Journal 423:534-38.
Ryden, B. S. and Terndrup, D.M. 1994. The Flattening Distribution of Dwarf Elliptical Galaxies in the Virgo Cluster. Astrophysical Journal 424:43-50.
Ryden, B. S. 1993. Self-similar Collapse of Axisymmetric Systems. Astrophysical Journal 418:4-10.
Ryden, B. S.; Lauer, T. R.; and Postman, M. 1993. The Shapes of Brightest Cluster Galaxies. Astrophysical Journal 410:515-19.
My research interests are centered on cosmology, particularly the early universe and the large-scale structure of the universe. Within the area of early-universe physics, I have worked on primordial nucleosynthesis, including both non-standard variations of nucleosynthesis, and the use of nucleosynthesis to constrain particle properties. I have also examined the thermodynamics of particles in the early universe. In large-scale structure, I have worked on testing various models for structure formation-especially non-Gaussian models. I have also done analytic work on the evolution of density perturbations.
Fry, J. N. and Scherrer, R. J. 1994. Skewness in Large-Scale Structure and Non-Gaussian Initial Conditions. Astrophysical Journal 429:36.
Brainerd, T. G.; Scherrer, R.J.; and Villumsen, J. V. 1993. Linear Evolution of the Gravitational Potential: A New Approximation for the Nonlinear Evolution of Large-Scale Structure. Astrophysical Journal 418:570.
De Laix, A.A., and Scherrer, R. J. 1993. Improved Cosmological Constraints on Neutrino-Producing Decaying Particles. Physical Review D 48:562.
Gratsias, J.; Scherrer, R.J.; Steigman, G.; and Villumsen, J.V. 1993. Seeded Hot Dark Matter Models with Inflation. Astrophysical Journal 405:30.
Scherrer, R. J. and Spergel, D. N. 1991. How Constant is the Fermi Coupling Constant? Physical Review D. 47:4774.
My research interests are in two main areas, the Galactic Center and interstellar dust, which I study with infrared spectroscopy and infrared imaging. Currently I am working with a graduate student to measure the mass distribution in the bulge of the Milky Way and to search for dynamical evidence for a bar using stellar kinematics. We are also studying the stellar population in the central few parsecs of the Galactic Center. My research on the interstellar medium has concentrated on the composition and excitation of tiny particles, midway between grains and molecules in size, which emit continuum from 1 to 25-micron and emission features at 3.3, 6.2, 7.7, 8.6, and 11.3-micron. These particles dominate the mid-infrared emission of the diffuse interstellar medium of our own and other galaxies. I am also interested in the composition of grains seen in absorption in the interstellar medium, particularly hydrocarbon grains in molecular clouds and the diffuse interstellar medium.
Blum, R. D.; DePoy, D. L.; and Sellgren, K. 1995. A Comparison of Near Infrared Spectra of the Galactic Center Compact He I Emission Line Sources and Early Type Mass Losing Stars. Astrophysical Journal , in press.
Sellgren, K.; Smith, R. G.; and Brooke, T. Y. 1994. The 3.2-3.6 Micron Spectra of Monoceros R2/IRS-3 and Elias 16. Astrophysical Journal 433:179-186.
Blum, R. D.; Carr, J. S.; DePoy, D. L.; Sellgren, K.; and Terndrup, D. M. 1994. Radial Velocities of M Giants at 300 pc Projected Radius from the Galactic Center. Astrophysical Journal 422:111.
Sellgren, K.; Werner, M. W.; and Dinerstein, H. L. 1992. Scattering of Infrared Radiation by Dust in NGC 7023 and NGC 2023. Astrophysical Journal 400:238.
Sellgren, K.; Luan, L.; and Werner, M. W. 1990. The Excitation of 12 Micron Emission from Very Small Particles. Astrophysical Journal 359:384.
Sellgren, K.; McGinn, M. T.; Becklin, E. E.; and Hall, D. N. B. 1990. Velocity Dispersion and the Stellar Population in the Central 1.2 Parsecs of the Galaxy. Astrophysical Journal 359:112.
Sellgren, K.; Tokunaga, A. T.; and Nakada, Y. 1990. The 3.3-micron Feature, H2, and Ionized Gas in the Orion Bar. Astrophysical Journal 349:120.
My colleagues and I have been doing pioneering work in the burgeoning field of astroparticle physics and early universe cosmology. We have used observational data and cosmological models to establish the matter-antimatter asymmetry of the universe, opening the door for the marriage between early universe cosmology and grand unified models of elementary particle physics. Recently, I have concentrated on Big Bang Nucleosynthesis (BBN), using the comparison between the predicted and observed primordial abundances of the light elements to test and constrain the standard hot big bang model of cosmology, as well as the standard model of high energy physics. My collaborators and I have analyzed the observations and evolution of the abundances of deuterium, helium-3, helium-4 and lithium-7 and compared the inferred primordial abundances with those predicted by BBN to test the internal consistency of primordial nucleosynthesis and to constrain the universal density of baryons and the properties of new elementary particles beyond those in the standard model. It emerges that, despite some potential challenges from recent observations, the standard hot big bang model is consistent provided that the density of baryons in the universe lies in a very narrow range such that although most of the baryons in the universe are ``dark'', most of the ``dark matter'' in the universe is not baryonic-the ultimate Copernican principle!
Steigman, G. and Tosi, M. Galactic Evolution of D and 3He. 1992. Astrophysical Journal 401:150.
Steigman, G. and Walker, T.P. 1992. Production of Li, Be, and B in the Early Galaxy. Astrophysical Journal Letters 385:L13-L16.
Olive, K.A.; Steigman, G. and Walker, T.P. 1991. The Upper Bound to the Primordial Abundance of Helium and the Consistency of the Hot Big Bang Model. Astrophysical Journal Letters 380:L1.
Walker, T.P.; Steigman, G.; Schramm, D.N.; Olive, K.A.; and Kang, H-S. 1991. Primordial Nucleosynthesis Redux. Astrophysical Journal 376:51-69.
I am currently working on several observational programs to determine the composition and evolutionary history of stars in the nuclear bulge of the Milky Way. Stars in the bulge are among the oldest in the galaxy and have a high content of elements heavier than helium, which means that the center of the Galaxy experienced many cycles of element production very early in its history. The details of the previous generations are very sketchily known, however, and require high resolution optical and infrared spectroscopy. In collaboration with students Robert Blum and Glenn Tiede, I am studying the orbital motions of stars in the bulge and inner disk of the Galaxy, which will reveal the mass distribution in the central kiloparsec and constrain the size and orientation of the Galaxy's bar. I am also beginning an extensive study of the kinematics of bulges of galaxies which are similar to the Milky Way, with student Leslie Kuchinski.
Ryden, B.S. and Terndrup, D.M. 1994. The Flattening Distribution of Dwarf Elliptical Galaxies in the Virgo Cluster. Astrophysical Journal 425:43-50.
Terndrup, D.M. and Walker, A. R. 1994. Blue Horizontal Branch Stars in NGC 6522 and Baade's Window. Astronomical Journal 107:1786.
Suntzeff, N.B.; Terndrup, D. M.; Mateo, M.; Geisler, D.; and Weller, W. 1993. Spectroscopy of Giants in the Sextans Dwarf Spheroidal Galaxy. Astrophysical Journal 418:208-228.
Walker, A. R. and Terndrup, D. M. 1991. The Metallicity of RR Lyrae Stars in Baade's Window. Astrophysical Journal 378:119-126.
My principal research interests involve multiwavelength studies of classical and X-ray novae, X-ray binaries, deep imaging and spectroscopic surveys, and spectroscopic instrumentation. With my collaborators, I have obtained and analyzed X-ray, ultraviolet, optical, and radio observations of recent X-ray novae and black hole candidates. My optical spectroscopic and photometric observations are obtained with the Perkins telescope and the 4.5-m MMT. This work has helped to establish these systems as containing massive compact objects as well as constraining models for their major episodic outbursts. In addition, I have an active program involving the physics of classical novae. This program utilizes optical spectrophotometry and high resolution spectroscopy to study the physical conditions, abundances, and dynamics of their ejecta. These observations help to constrain thermonuclear runaway models on white dwarf stars which account for their outbursts.
Wagner, R.M.; Starrfield, S.G.; Hjellming, R.M.; Howell, S.B.; and Kreidl, T.J. 1994. ROSAT Observations of the Black Hole Candidate V404 Cygni in Quiescence. Astrophysical Journal Letters 429:L25-L28.
Hauschildt, P.H.; Starrfield, S.; Austin, S.; Wagner, R. M.; Shore, S. N.; and Sonneborn, G. 1993. Non-LTE Model Atmosphere Analysis of Nova Cygni 1992. Astrophysical Journal 422:831-844.
Wagner, R.M.; Kreidl, T.J.; Howell, S.B.; and Starrfield, S.G. 1992. Periodic Photometric Variability of the Black Hole Binary V404 Cygni. Astrophysical Journal Letters 401:L97-L100.
Hollis, J.M.; Wagner, R.M.; and Oliversen, R.J. 1990. Symmetrical Jet Action in the R Aquarii Binary System. Astrophysical Journal Letters 351:L17-L20.
My research interests lie at the interface of particle physics and cosmology, with particular emphasis on neutrino physics and big bang nucleosynthesis. Ongoing and proposed research includes projects on bounds on the massive tau neutrino from big bang nucleosynthesis; predictions for primordial He-4 from big bang nucleosynthesis; vacuum oscillation solutions to the solar neutrino problem involving sterile neutrinos; and mechanisms for Li, Be, and B production in the early Galaxy. Over the next year I plan to continue research that uses cosmological environments to examine particle physics as well as research that looks to particle physics for the solution to problems in cosmology.
Walker, T.P.; Kang, H-S.; Kawasaki, Kernan, Scherrer, and Steigman, G. 1994. Constraining a Massive Tau Neutrino with Primordial Nucleosynthesis. Nuclear Physics B, 419:105.
Walker, T. P.; Steigman, G.; Fields, B.; Olive, K. A.; and Schramm, D.N. 1993. Pop II 6Li as a Probe of Nucleosynthesis and Stellar Evolution. Astrophysical Journal Letters 415:L35.
Steigman, G. and Walker, T.P. 1992. Production of Li, Be, and B in the Early Galaxy. Astrophysical Journal Letters 385:L13-L16.
Walker, T.P.; Steigman, G.; Schramm, D.N.; Olive, K.A.; and Kang, H-S. 1991. Primordial Nucleosynthesis Redux. Astrophysical Journal 376:51-69.
Walker, T.P.; Chivukula, S.; Cohen, A.; and Dimopoulos, S. 1990. Bounds on Halo Particle Interactions from Interstellar Calorimetry. Physical Review Letters 67:957.
My research focuses on cosmology and the formation of structure in the universe. My interests also extend to statistical analyses of galaxy clustering and numerical simulations of the formation of galaxies and large-scale structure. The underlying goals of this work are to test hypotheses about the origin of primordial density fluctuations and to constrain the values of cosmological parameters and the nature of the dark matter in galaxies and galaxy clusters. I am also a participant in the Sloan Digital Sky Survey, a project that will use a special-purpose telescope to produce a redshift survey of 1,000,000 galaxies and 100,000 quasars, and a CCD photometric survey of 50,000,000 galaxies and 100,000,000 stars.
Cole, S.; Fisher, K.; and Weinberg, D.H. 1994. Fourier Analysis of Redshift Space Distortions and the Determination of W. M.N.R.A.S. 267:785.
Weinberg, D. H. 1992. Reconstructing Primordial Density Fluctuations. I. Method. M.N.R.A.S. 254:315.
Katz, N.; Hernquist, L.; and Weinberg, D.H. 1992. Galaxies and Gas in a Cold Dark Matter Universe. Astrophysical Journal Letters 399:L109.
Weinberg, D.H., and Cole, S. 1992. Non-Gaussian Fluctuations and the Statistics of Galaxy Clustering. M.N.R.A.S. 259:652.
Weinberg, D. H.; Szomoru, A.; Guhathakurta, P.; and van Gorkom, J. H. 1991. On the Population of HI Dwarf Galaxies. Astrophysical Journal Letters 372:L13.
Observational studies of late-type stars have been the focus of my research. Most projects have been applications of infrared, optical, and UV spectroscopy, infrared spectrophotometry, and narrow-band photometry on my eight-color near-infrared system. I have recently surveyed the Large Magellanic Cloud for red supergiants and the brightest AGB stars and have determined their effective temperatures and bolometric magnitudes. I am currently surveying the southern galactic plane for faint red supergiants that can be used to trace the spiral-arm structure of the Galaxy in distant, obscured regions. Other projects include improved classification of faint red dwarfs down to the hydrogen-burning limit, a search for dwarf carbon stars, the identification of molecular bands in the infrared spectra of S stars, and a study of the chromospheres of carbon stars through HST observations of their ultraviolet spectra.
MacConnell, D.J.; Wing, R.F.; and Costa, E. 1992. Red Supergiants in the Southern Milky Way. I. Search and Classification Techniques. Astronomical Journal 104: 821.
Wing, R.F. 1991. Stellar Photometry and Spectrophotometry in the Infrared. In The Infrared Spectral Region of Stars, ed. C. Jaschek and Y. Andrillat (Cambridge Univ. Press), p. 275.
Wing, R.F. 1989. Red Giants near the South Galactic Pole: A Test for an Abundance Gradient. In The Gravitational Force Perpendicular to the Galactic Plane, ed. A.G.D. Philip and P.K. Lu (L. Davis Press), p. 167.
Wing, R.F. 1989. Mapping the Structure of the Southern Milky Way. Revista Mexicana de Astronomia y Astrofisica 19:57.
Hinkle, H.K.; Lambert, D.L.; and Wing, R.F. 1989. Zirconium Sulfide in S Stars. M.N.R.A.S. 238:1365.
In addition to the above required core courses, students may choose additional courses, including the following:
Graduate Committee ChairYou can also request information by electronic mail, by sending e-mail to: gradchair@astronomy.ohio-state.edu
Department of Astronomy
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