Title: Galaxy Build-up at Cosmic Dawn: Lessons from Ultra-Deep HST and Spitzer/IRAC Observations
Abstract:
  Thanks to the revolutionary capabilities of the Hubble Space Telescope we have made enormous progress in our exploration of the early universe over the last two decades. Hubble allowed us to push the observational frontier back to z~10-11, to only ~400 Myr after the Big Bang. To date, we have identified almost 1000 likely galaxies at z>6, with up to 20 credible candidates at z~9-11. These unprecedented samples allow us to directly track the build-up of galaxies in the heart of the cosmic reionization epoch, providing an increasingly more complete picture. For instance, in combination with deep data from the Spitzer Space Telescope we can now probe the evolution of the stellar mass density over 96% of cosmic history. In this talk I will provide an overview of recent observational progress coming from very deep HST and Spitzer/IRAC observations as well as from ground-based imaging and spectroscopy to study the first generations of galaxies. In particular, I will present recent results on the build-up of the galaxy UV luminosity functions, the cosmic SFR densities, as well as stellar mass densities out to z~10, and I will highlight the exciting possibilities that are just around the corner based on several major upcoming and planned telescopes.