IAU01236
Presentation type requested: ORAL
GALAXY EVOLUTION FROM MORPHOLOGY AND SEDS: GEMS
Steven V. W. Beckwith
Space Telescope Science Institute

The GEMS Survey (Galaxy Evolution from Morphology and SEDs) has taken the largest area deep image ever taken with the Hubble Space Telescope, a ~30'x30' ACS mosaic in the F606W and F850LP bands. Together with ~10,000 existing redshifts, we can explore the evolution of the rest-frame B-band morphologies and sizes of the galaxy population since z<1.1. In this talk, we discuss the morphology of galaxies, focusing on the morphologies of the reddest and bluest galaxies. We find that the vast majority of luminosity density in red galaxies at z~0.7 is in morphologically early-type galaxies, with large stellar bulges. No more than 20% of the light in the red galaxy population is from galaxies that are red by virtue of their dust content, primarily edge-on spiral galaxies. Focusing on the star-forming of starbursting galaxies, we find that many luminous star-forming galaxies have highly peculiar morphologies indicative of interactions. In contrast, we find that most low-luminosity star-forming galaxies have lower surface brightness, and morphologies typical of local starforming galaxies in the local Universe. This result tentatively suggests that the demise of the luminous blue galaxy population since z~1 tracks primarily the declining importance of gas-rich galaxy mergers since that time.

Rix, Hans-Walter; Barden, Marco; Bell, Eric; Caldwell, John; Borch, Andrea; Haeussler, Boris; Jogee, Shardha; de Marchi, Guido; McIntosh, Dan; Meisenheimer, Klaus; Peng, Chien; Somerville, Rachel; Lutz, Wisotzki; Wolf, Christian; Jahnke, Knud; Sanchez, Sebastian F.;

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