The First Stars: Clues from quasar absorption systems

Abstract

Astronomers now have at their disposal telescopes and instruments that allow them to look back in time over most of the history of the Universe, from the present epoch to less than a billion years after the Big Bang, when the Universe was still in its infancy. Using quasars (the bright nuclei of distant galaxies) as background sources of light, we can follow the evolution of galaxies and of the matter between them from the First Stars to the rich diversity of the Universe today. In this article, I focus on recent developments in the study of the most metal-poor gas seen in the spectra of quasars, whose properties can be used to infer the nature of the First Stars and, in some cases, even determine the universal fraction of baryons. This journal is © 2011 The Royal Society.