A closer look at the reionization sources: clustering, line emission and feedback

The epoch of reionization marks a major phase transition of the Universe,
during which the intergalactic medium became transparent to UV photons.
Over the last few years, searches have intensified to identify the
population of high redshift galaxies that might be responsible for this
process and to constrain their properties. In this talk I will discuss
recent efforts to address the open problems in our understanding of the
sources of reionization. I will present the results from a deep HST
imaging program providing the first observational match to the theoretical
prediction that reionization fronts are generated within significant
overdensities of faint galaxies. I will show our ongoing analysis of the
HST Frontier Fields survey and the resulting limits on the cut-off
imprinted by photo-ionization feedback on the UV luminosity function at
high redshift. Finally, I will discuss a multi-band study of z~7 galaxies
providing evidence for strong line emission in the optical rest-frame
region and the first constraints on the escape fraction of ionizing
photons from these early galaxies.