| One of the most exciting frontiers in astronomy is to understand how the first galaxies in the universe built up and evolved, during the first 400-800 Myr of the universe (redshifts z~7-10+). Investigating the properties of these early galaxies, on the basis of the observations, has been almost impossible due to the need for extraordinarily deep near-IR observations. This entire situation is about to change as a result of the new WFC3/IR camera just installed on the Hubble Space Telescope -- which is 20-40x more powerful than previous cameras. Our team has been awarded 192 orbits to use this camera to obtain ultra-deep near-IR observations to study early galaxy formation. We expect to identify >100 galaxies at z~7-10 from the new observations - >5x more than the 15-20 galaxies currently known at these epochs. The goal is to determine the galaxy luminosity function and its shape to very faint luminosities, characterize galaxy properties (sizes, structure), estimate their star formation rate density, and the contributions they made to the reionization of the universe. Here we request funding for a thesis student in Leiden to help lead this analysis. The student will work with the PI to define the selection of high-redshift galaxies from this large program and determine the properties (size, surface brightness, luminosity function) of this population, incorporating the results with wide-area searches for z~7-9 galaxies. The student will then contrast the properties of z~7-9 galaxies with those at later times to investigate how galaxies form. |
