To appear in `First Light in Universe', Saas-Fee
Advanced Course 36, Swiss Soc. Astrophys. Astron. in press, 2007.
astro-ph/0701024
For a PDF version of the article, click
here.
OBSERVATIONS OF THE HIGH REDSHIFT UNIVERSE
Richard S. Ellis
Astronomy Department, California Institute of Technology
rse@astro.caltech.edu
Abstract. In this series of lectures, aimed for non-specialists,
I review the considerable progress that has been made in the past decade
in understanding how galaxies form and evolve. Complementing the
presentations of my theoretical colleagues,
I focus primarily on the impressive achievements of observational
astronomers. A credible framework, the
CDM model, now exists
for interpreting these observations: this is a universe with dominant
dark energy
whose structure grows slowly from the gravitational clumping of dark matter
halos in which baryonic gas cools and forms stars. The standard
model fares well in matching the detailed properties of local galaxies,
and is addressing the growing body of detailed multi-wavelength
data at high redshift. Both the star formation history and the assembly
of stellar mass can now be empirically traced from redshifts z
6 to the
present day, but how the various distant populations relate to one
another and precisely how stellar assembly is regulated by feedback
and environmental processes remains unclear. In the latter part of my
lectures, I discuss how these studies are being extended to locate
and characterize the earliest sources beyond z
6. Did
early star-forming galaxies contribute significantly to the reionization
process and over what period did this occur? Neither theory
nor observations are well-developed in this frontier topic but
the first results are exciting and provide important guidance on how we
might use more powerful future facilities to fill in the details.
Table of Contents
Surveys