Abstract

How and when did galaxies reionize the universe (if they did)? I will present recent observational results from two projects aimed at answering this question by finding and characterizing the first galaxies. The first project (BORG) aims to find the brightest galaxy candidates above z=7, most suitable for spectroscopic follow-up. The second project (GLASS) exploits the magnifying power of foreground clusters of galaxies and the spectroscopic capabilities of HST to measure spectra of galaxies from the epoch of cosmic reionization to z=0.5. I will summarize some highlights and their implications for our understanding of the sources of reionization. If there is time, I will describe a new technique to measure black holes masses at cosmological redshifts, thus providing insights into an alternative potential source of reionizing photons.