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 LambdaCDM 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 appeq 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 appeq 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

ROLE OF OBSERVATIONS IN COSMOLOGY & GALAXY FORMATION
The Observational Renaissance
Observations Lead to Surprises
Recent Observational Milestones
Concordance Cosmology: Why is such a curious model acceptable?
Lecture Summary

GALAXIES & THE HUBBLE SEQUENCE
Introduction: Changing Paradigms of Galaxy Formation
Galaxy Morphology - Valuable Tool or Not?
Semi-Analytical Modeling
A Test Case: The Galaxy Luminosity Function
The Role of the Environment
The Importance of High Redshift Data
Lecture Summary

COSMIC STAR FORMATION HISTORIES
When Did Galaxies Form? Searches for Primeval Galaxies
Local Inventory of Stars
Diagnostics of Star Formation in Galaxies
Cosmic Star Formation - Observations
Cosmic Star Formation - Theory
Unifying the Various High Redshift Populations
Lecture Summary

STELLAR MASS ASSEMBLY
Motivation
Methods for Estimating Galaxy Masses
Results: Regular Galaxies 0 < z < 1.5
Stellar Masses from Multi-Color Photometry
Results: Stellar Mass Functions 0 < z < 1.5
Results: Stellar Mass Functions z > 1.5
Quiescent Galaxies with 2 < z < 3
Lecture Summary

WITNESSING THE END OF COSMIC REIONIZATION
Introduction - Some Weighty Questions
The Gunn-Peterson Test and SDSS QSOs
Metallicity of the High Redshift IGM
Linear Polarization in the WMAP Data
Stellar Mass Density at z appeq 5-6
Lecture Summary

INTO THE DARK AGES: LYMAN DROPOUTS
Motivation
Contamination in z appeq mathend000#6 Dropout Samples
Cosmic Variance
Evolution in the UV Luminosity Density 3 < z < 10?
The Abundance of Star Forming Sources Necessary for Reionization
The Spitzer Space Telescope Revolution: Stellar Masses at z appeq 6
Lecture Summary

LYMAN ALPHA EMITTERS AND GRAVITATIONAL LENSING
Strong Gravitational Lensing - A Primer
Creating a Cluster Mass Model
Lensing in Action: Some High z mathend000# Examples
Lyman alpha Surveys
Results from Narrow Band Lyalpha Surveys
Results from Lensed Lyalpha Surveys
Lecture Summary

COSMIC INFRARED BACKGROUND
Motivation
Methodogy
Recent Background Measurements
Fluctuation Analyses
EBL Constraints from TeV Gamma Rays
Lecture Summary

EPILOGUE: FUTURE PROSPECTS
Introduction
The Next Five Years
Beyond Five Years

REFERENCES

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