Observations of the z=1-4 Universe

California Institute Of Technology, Pasadena CA

Investigators

Abstract

AST-0070773 Steidel This work involves the detailed study of the physical properties, large-scale distribution, and star forming characteristics of high redshift galaxies. The PI will use wide-field imaging to map out the large scale structure of the luminous material and combine this with quasar absorption line studies to map out and identify the associated intermediate redshift (z=1.3 to 2.5) gas. The star formation rates for these intermediate redshift objects, their chemical composition, and their association with the gas will then be analyzed using near IR spectroscopy. These studies focus on the properties of galaxies and their large--scale spatial distribution during an interval of cosmic time when the universe was between 10% and 40% of its current age. This time interval is believed to be the epoch when when the galaxy formation activity that produced the galaxies of the present-day universe was at its peak and when most of the stars in the present day universe formed. In the last few years, facilities and techniques have become available, which allow us to gather extensive empirical data on galaxies at these early cosmic epochs. The studies proposed here will use the facilities of the Palomar and Keck observatories to: 1) ``map'' the large-scale structure traced by early galaxies over volumes of space comparable to the most ambitious galaxy surveys of the local universe 2) compare the galaxy distribution at early epochs to the properties of the diffuse intergalactic gas in the same volumes (observed using complementary techniques) 3) explore new techniques for finding and studying large samples of galaxies in the time interval that is currently least accessible to observation-- when the universe was ``middle aged'' and 4) measure the chemical content and masses of significant samples of these early galaxies. All of these studies are intended to make significant progress toward a physical understanding of the galaxy formation process, in the context of cosmological models in which galaxy formation and evolution is the observable manifestation of the changing distribution of matter in the universe as a function of time. Funding for this project was provided by the NSF program for Extragalactic Astronomy & Cosmology (AST/EXC). ***