Light after the First Dark Ages: Constraints on Reionization from Spitzer, HST and WMAP

Ranga-Ram Chary (Caltech)

Deep HST/WFC3 observations and gamma-ray bursts are providing our first window into galaxy formation at the epoch of reionization i.e. z>6. Archival Spitzer observations of these deep fields are measuring the stellar mass in these galaxies and possibly detecting the remnants of the first epoch of star-formation. By balancing the ionizing photon budget from these galaxies with that inferred from the WMAP electron-scattering optical depth, we can gain insights into what the reionization history of the Universe might be like. I will present our current understanding on this topic and discuss possibilities for constraining the reionization history using observations from a future, outer solar system platform.