0 Assigned ID: 1495 ----- Attempting Submission 1 (Fri Mar 01 14:54:32 GMT 2013) ----- HST Phase I Proposal 1495 (cyc21_a.apt) successfully submitted. ----- Attempting Submission 2 (Sat Mar 02 00:52:02 GMT 2013) ----- We propose to analyze the data of the Hubble Frontier Fields, in order to discover and study galaxies at the highest redshifts and to an unprecedented depth. The redshift range of z~10-12 marks the beginning of the IGM reionization and remains as HST's last frontier. In the framework of the CLASH and related projects, our team has succeeded in finding the most distant galaxies. We will carry out a systematic search for galaxy candidates at z~10-12 in the proposed deep observations. At this redshift range, most of the spectral features are shifted longward of the WFC3/IR bands, and additional data are therefore needed in order to secure the candidates and study their intrinsic properties. We will (1) obtain deep photometry in complementary ground-based K-band observations; (2) estimate the global star-formation rate density; (3) measure the sources' UV continuum slope and (4) carry out ALMA observations to study the dust content. Finally, we will estimate the effect of these young galaxies in ionizing the IGM. Our study will serve as an ideal bridge between HST and JWST in exploring the cosmic dawn. COSMOLOGY Default Medium false false false false false SUPPORTED