Tassos Fragos (Harvard CfA-Smithsonian/ITC)

Evolution of X-ray Binaries Across Cosmic Time and Energy Feedback at High Redshift

High redshift galaxies are unique laboratories for studying the formation and evolution of X-ray binary (XRB) populations on cosmological timescales, as they probe metallicities and star-formation rates not present in the local universe. I will present results from a large scale population synthesis study that models the XRB populations from the first galaxies of the universe until today. We use as input in our modeling the Millennium II Cosmological Simulation and the updated semi-analytic galaxy catalog by Guo et al. (2011), in order to self-consistently account for the star formation history and metallicity evolution of the universe. Our modeling, which is compared to the most recent Chandra surveys of distant galaxies, gives prediction about the integrated specific X-ray luminosity as a function of redshift, as well as the evolution of the galaxy X-ray luminosity function with redshift. Finally, I will discuss the the possible energy feedback of XRBs in the re-ionization and thermal evolution of the universe at early times.