Published in The First Galaxies, Astrophysics and Space Science Library, Volume 396. ISBN 978-3-642-32361-4. Springer-Verlag Berlin Heidelberg, 2013, p. 223.
arxiv.org/abs/1205.1543

For a PDF version of the article, click here.

OBSERVING THE FIRST GALAXIES

James S. Dunlop


Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh, EH9 3HJ, UK


Abstract: I endeavour to provide a thorough overview of our current knowledge of galaxies and their evolution during the first billion years of cosmic time, corresponding to redshifts z > 5. After first summarizing progress with the seven different techniques which have been used to date in the discovery of objects at z > 5, I focus thereafter on the two selection methods which have yielded substantial samples of galaxies at early times, namely Lyman-break and Lyman-α selection. I discuss a decade of progress in galaxy sample selection at z ≃ 5 - 8, including issues of completeness and contamination, and address some of the confusion which has been created by erroneous reports of extreme-redshift objects. Next I provide an overview of our current knowledge of the evolving ultraviolet continuum and Lyman-α galaxy luminosity functions at z ≃ 5 - 8, and discuss what can be learned from exploring the relationship between the Lyman-break and Lyman-α selected populations. I then summarize what is known about the physical properties of these galaxies in the young universe, before considering the wider implications of this work for the cosmic history of star formation, and for the reionization of the universe. I conclude with a brief summary of the exciting prospects for further progress in this field in the next 5-10 years. Throughout, key concepts such as selection techniques and luminosity functions are explained assuming essentially no prior knowledge. The intention is that this chapter can be used as an introduction to the observational study of high-redshift galaxies, as well as providing a review of the latest results in this fast-moving research field up to the end of 2011.


Table of Contents

INTRODUCTION

WHY REDSHIFT z > 5

FINDING GALAXIES AT z > 5: SELECTION TECHNIQUES
Lyman-break selection
Lyman-α selection

LUMINOSITY FUNCTIONS
High-redshift evolution of the LBG luminosity function
High-redshift evolution of the Lyman-α luminosity function
The LBG-LAE connection

GALAXY PROPERTIES
Stellar masses
Star-formation histories
Ultraviolet slopes
Galaxy sizes and morphologies
Clustering

GLOBAL PERSPECTIVE
A consistent picture of galaxy evolution?
Cosmic reionization

CONCLUSION AND FUTURE PROSPECTS

REFERENCES

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