Patrick S. Osmer

Chair and Professor of Astronomy 1993 - present
Distinguished Professor of Mathematical and Physical Sciences  2004 - present

B.S., Case Institute of Technology 1965
Ph.D., California Institute of Technology 1970

Previous Positions Held:

Curriculum Vitae (PDF file)

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 research includes deep multicolor surveys for quasars, which also yield valuable information on faint galaxies and on stars in the galactic halo, and their relation to galaxies.  I am also very interested in the evolutionary relations between quasars and their host galaxies.

The Deep Multicolor Survey:


Some Recent Refereed Publications:

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 (erratum, 438, 506).

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, 436, 678.

Hall, P. B., Osmer, P.S, Green, R. F., Porter, A. C., and Warren, S. J. 1996, A Deep Multicolor Survey. I. Imaging Observations and Catalog of Stellar Objects, ApJ Supp., 104, 185.

Hall, P. B., Osmer, P.S, Green, R. F., Porter, A. C., and Warren, S. J. 1996, "A Deep Multicolor Survey. II. Initial Spectroscopy and Comparison with Expected Quasar Number Counts," ApJ, 462, 614 (erratum, 471, 1073)

Kennefick, J. D., Osmer, P. S., Hall, P. B., and Green, R. F. 1997, "A Deep Multicolor Survey. III. Additional Spectroscopy and Implications for the Number Counts of Faint Quasars," AJ, 114, 2269.

Popowski, P. A., Weinberg, D. H., Ryden, B. S., and Osmer, P. S., 1998, “Quasar Clustering and Spacetime Geometry,”  Ap.J., 498, 11

Liu, C. T., Green, R. F., Hall, P. B., Osmer, P. S., 1998, “Luminosity Functions and Evolution of Blue Galaxies in a Deep Multicolor CCD Field Survey,”  A.J., 116, 1082

Osmer, P. S., Kennefick, J. D., Hall, P. B., and Green, R. F. 1998, "A Deep Multicolor Survey. IV. The Electronic Stellar Catalog," ApJSupp, 119, 189

Martini, P., and Osmer, P. S. 1998, “A Deep Multicolor Survey. V. The M Dwarf   Luminosity Function,”  A.J., 116, 2513

Conti, A., Kennefick, J. D., Martini, P., and Osmer, P. S. 1999, “Quasar Candidates in the Hubble Deep Field,”  A.J., 117, 645

Monier, E. M., Kennefick, J. D., Hall, P. B., Osmer, P. S., Smith, M. G., Dalton, G. B., and Green, R. F. 2002, “The BTC40 Survey for Quasars at 4.8 < z < 6,”  A.J., 124, 2971.


Other Recent Publications

Osmer, P. S. 1994, "Quasars," in "The Farthest Things in the Universe," J. M. Pasachoff, H. Spinrad, P. S. Osmer and E. Cheng (Cambridge Univ. Press, Cambridge), 57

Osmer, P. S. 1996,  “The Sharp End of Quasars,” Nature (News and Views), 384, 415

Osmer,  P. S., Kennefick, J., Hall, P. B., and  Green, R. F. 1997, “Spectroscopic Observations of Quasar Candidates from a Deep Multicolor Survey,”  , in “The Hubble Space Telescope and the High Redshift Universe,”, ed. N.R. Tanvir, A. Aragon-Salamanca, & J.V. Wall (World Scientific: Singapore), 405

Hall, P.B., Kennefick, J.D., Osmer, P.S., Smith, M.G., & Green, R.F. 1998, “The Big Faint Quasar Survey,”  BAAS, 30, 768

Osmer, P. S. 1998, “The Evolution of Quasars and Their Clustering,”  in “New Horizons from Multi-Wavelength Sky Surveys, IAU Sym. No. 179” ed. B.J. McLean, D.A. Golombeck, J.J.E. Hayes, & H.E. Payne, 249.

Osmer, P. S. 1998, “The Evolution of Quasars at High Redshift and Their Connection with Galaxies,” , in “The Young Universe: Galaxy Formation and Evolution at Intermediate and High Redshift,” ed. S. D’Odorico, A. Fontana, & E. Giallongo, ASP Conf. Ser., 146, 1

Osmer, P. S., & Shields, J. C. 1999,  “A Review of Line and Continuum Correlations in AGNs,” in “Quasars and Cosmology,” ed. G. Ferland, ASP Conf. Series, 162, 235

Osmer, P. S., 1999,  “Quasars,” , to appear in Proc. of IAU Sym. 194, “Activity in Galaxies and Related Phenomena,” ed. Y. Terzian, E. Khachikian, & D. Weedman, ASP. Conf. Series (astro-ph/9901238)

Osmer, P. S., 2003, “The Evolution of Quasars,”  to appear in Carnegie Observatories Astrophysics Series, Vol. 1: Coevolution of black Holes and Galaxies, ed. L C. Ho (Cambridge: Cambridge Univ. Press) (astro-ph/0304150)


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Updated: 2006 Mar. 26