The Hubble Space Telescope (HST) Ultra Deep Field 2012 (UDF12) provides the deepest near-infrared imaging to date of the high redshift Universe. By effectively doubling the depth of the Wide Field Camera 3 near-infrared imaging in the UDF, with valuable diagnostic imaging through a new additional filter, the UDF12 program considerably enhances our understanding of the rest-frame UV properties of star-forming galaxies in the crucial redshift range z=7-10 when the reionization process is ending. We present the first unbiased measurements of the UV continuum slopes of galaxies at z=7 (and the first meaningful measures at z=8), thereby setting new constraints on the age, metallicity and ionizing photon escape fractions for early galaxies . We also present new results on the sizes of these primeval galaxies with more accuracy than hitherto, and set new constraints on their stellar masses. These new measurements of the physical properties of the emerging population of young galaxies are compared with the predictions of the latest theoretical models of galaxy formation.
|Publication status||Published - 1 Jan 2013|
|Event||AAS, 221st Meeting of the American Astronomical Society - California, Long Beach, United Kingdom|
Duration: 6 Jan 2013 → 10 Jan 2013
|Conference||AAS, 221st Meeting of the American Astronomical Society|
|Period||6/01/13 → 10/01/13|