Qualifying Exam/2nd-Year Defense
"Revealing the Brightest Galaxies at Cosmic Brunch"
The star formation density in the universe ramps up smoothly at early times and peaks at z~2, or "cosmic high-noon," before turning over. Little is known about the mechanisms that dominate stellar mass build-up at z>2, or "cosmic brunch." This mystery of galaxy growth can be addressed observationally using large numbers of galaxies over a large dynamic range in, for example, stellar mass, star formation rate, and halo mass. Currently, the most efficient way to accomplish this is with large-area, multi-wavelength photometric surveys. In this talk I present the HETDEX/NEWFIRM survey, the K-band imaging survey of the 28 deg^2 HETDEX fall field, which is being carried out by a number of astronomers here at UT. In addition, I will present my work using the field's optical imaging data (u', g', r', i', and z') from the Dark Energy Camera to construct a luminosity function for z=4 Lyman break galaxies (LBGs). The large area of the survey allows us to capture the most luminous and most rare galaxies in the universe, extending existing z=4 LBG luminosity functions at the bright-end. These bright galaxies are particularly interesting because they are the progenitors of today's richest galaxy clusters. Finally, I will advertise future work that will incorporate Spitzer/IRAC photometry, Herschel photometry, XMM/Newton observations, and HETDEX spectroscopy to investigate the relationships between star formation, modes of gas accretion, and environment during the epoch of cosmic brunch.
University of Texas at Austin