Ph.D. London, 1982
My main interests are Observational Cosmology and new astronomical instruments. My group (4 graduate students and one postdoc) gets most of its data from the Hubble Space Telescope (HST), the University of California's Lick Observatory (San Jose) and the Keck Observatory (Hawaii), which we operate with Caltech. These are such exciting times for astronomy, that most of us doubt that the research opportunities will ever be as good as during the next five years. The HST is producing excellent data, and Keck is 100 times faster than any other telescope in the world. It can easily make observations well beyond the reach of other telescopes, and it will have no competitors for 5 years. There is much more to do than we have time for, so we are using these advantages to tackle major questions with wide-spread implications for cosmology and galaxy formation.
1. We are measuring the cosmological abundance of deuterium, which will give the density of baryons in the universe ten times more accurately than is now known, and will help determine whether the dark matter in galaxies can be baryons, and whether there are missing dark baryons.
2. We are using the HST to detect the diffuse intergalactic medium in the far ultravioleta thirty-year goal in astrophysics.
3. We are using a combination of Keck and HST spectra to measure the cosmological abundances of heavy elements in the early universe.
I am building some equipment for the Keck telescope, and hope to begin larger instrumentation projects in the future. By the time you are here we will be working with the new Adaptive Optics System with Laser Guide Starts at Lick Observatory which will provide exceptional images and spectra in the near infrared, and we hope to be obtaining near-IR spectra of high redshift galaxies with the Keck Telescope.
Selected Publications:
QSO Emission Line Velocity Shifts and New Unbiased Redshifts. With X.M. Fan. Astrophys. J. Suppl., 79, 1 (1992).
A Survey of Very Low Redshift MG II Absorption Systems in QSO Spectra. With P. Boissé, et al. Astron. Astrophys. 262, 401 (1992).
Upper Limit on Periodicity in the 3-Dimensional Large-Scale Distribution of Matter. With J. Sandoval and X.-M. Fan. Astrophys. J. Suppl. 405, 57 (1992).
Statistical Issues Concerning Quasar Absorption Line Systems. Statistical Challenges in Modern Astronomy, Ed. G.J. Babu and E.D. Feigelson (Springer-Verlag), 83-102 (1992).
Lick Slit Spectra of Thirty-eight Objective Prism Quasar Candidates and Low Metallicity Halo Stars. Astrophys. J. 106, 426 (1993).
Far Ultraviolet Absorption Spectra of Quasars: How to Find Missing Hot Gas and Metals. With D.A. Verner, and P.D. Barthel. Astrophys. J. 20, (1994), in press.
Upper Limit on Metals in Quasar Lyman-a Forest Clouds: Absence of C IV Lines in Echelle Spectra. Astrophs. J. Lett., 424, L87 (1994).
On the Lack of Emission or Absorption in the Lyman Continuum of QSOs: What is the Source of the Lyman Continuum Radiation, and Where are the Broad Line Clouds? Bulletin Amer. Astron. Soc. 25, 1432 (1993).