AAS 207th Meeting, 8-12 January 2006
Session 52 Galaxy Surveys
Oral, Monday, 2:30-4:00pm, January 9, 2006, Delaware B

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[52.05] Mass-dependent star formation histories of field galaxies in the EGS

K. G. Noeske (Lick Observatory), Extended Groth Strip Collaboration

The Extended Groth Strip (EGS) survey combines panchromatic space- and ground based photometry, HST images, and high resolution spectroscopy. We use this dataset to study the history of star formation and stellar mass buildup in field galaxies out to redshift 1.4 .

From a combination of UV- and IR-derived star formation rates, and stellar and dynamical masses, we find that the star formation histories of field galaxies can be descibed by a Tinsley model with a mass-dependent parametrization of star formation histories, throughout the stellar mass range we can observe (> 9 dex Msun). Our results suggest that gradual gas exhaustion rather than strong merger-driven starbursts may largely drive the evolution of star formation in field galaxies over a wide range in mass and redshift, consistent with recent morphological studies of LIRGs, and star formation in mergers and pairs, at intermediate redshifts. A simple analytical parametrization can reproduce the observed star formation history in field galaxies at z<1.4, and can at least partially account for observed galaxy bimodality and 'downsizing' effects.

This work was supported by NSF grants AST 00-71198 and AST 00-71048, and made use of observations with the Spitzer Space Telescope, the Hubble Space Telescope, and the Galaxy Evolution Explorer.

The author(s) of this abstract have provided an email address for comments about the abstract: kai@ucolick.org

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