Abstract

Combining JWST With Gravitational Telescopes to detect the Galaxies Responsible For Cosmic Reionization

Hakim Atek (Ecole Polytechnique Federale de Lausanne)

Jean-Paul Kneib (EPFL), Johan Richard (CRAL) et al.

The identification of the first generation of galaxies and the possible sources of cosmic reionization is one of the foremost challenges in modern astrophysics. Great progress has been made in characterizing galaxy populations at redshift z=6-7 through photometric observations in blank fields. A complementary approach is to exploit the power of gravitational lensing offered by massive galaxy clusters, which gives access to the faintest sources at high redshift. Using director discretionary time, the Hubble Frontier Fields (HFF) initiative is aiming to peer deeper into the distant Universe by observing six lensing clusters down to a magnitude limit of ~ 29 AB. I will present here the latest HFF results from three lensing clusters, where we detect about 250 magnified galaxies at z=6-8 down to an absolute magnitude of M-uv = -15. I will show how combining JWST capabilities with gravitational telescopes will be a very efficient way to study the faintest galaxy populations ever observed at those redshifts and to demonstrate that galaxies are the main sources of cosmic reionization.

Talk