Martin, D. Christopher and Small, Todd and Schiminovich, David and Wyder, Ted K. and Pérez-González, Pablo G. and Johnson, Benjamin and Wolf, Christian and Barlow, Tom A. and Forster, Karl and Friedman, Peter G. and Morrissey, Patrick and Neff, Susan G. and Seibert, Mark and Welsh, Barry Y. and Bianchi, Luciana and Donas, José and Heckman, Timothy M. and Lee, Young-Wook and Madore, Barry F. and Milliard, Bruno and Rich, R. Michael and Szalay, Alex S. and Yi, Sukyoung K. and Meisenheimer, Klaus and Rieke, George (2007) The Star Formation and Extinction Coevolution of UV-Selected Galaxies over 0.05 < z < 1.2. Astrophysical Journal Supplement Series, 173 (2). pp. 415-431. ISSN 0067-0049 http://resolver.caltech.edu/CaltechAUTHORS:20100421-122354466
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We use a new stacking technique to obtain mean mid-IR and far-IR to far-UV flux ratios over the rest-frame near-UV, near-IR color-magnitude diagram. We employ COMBO-17 redshifts and COMBO-17 optical, GALEX far- and near-UV, and Spitzer IRAC and MIPS mid-IR photometry. This technique permits us to probe the infrared excess (IRX), the ratio of far-IR to far-UV luminosity, and the specific star formation rate (SSFR) and their coevolution over 2 orders of magnitude of stellar mass and over redshift 0.1 < z < 1.2. We find that the SSFR and the characteristic mass (M_0) above which the SSFR drops increase with redshift (downsizing). At any given epoch, the IRX is an increasing function of mass up to M_0. Above this mass the IRX falls, suggesting gas exhaustion. In a given mass bin below M_0, the IRX increases with time in a fashion consistent with enrichment. We interpret these trends using a simple model with a Schmidt-Kennicutt law and extinction that tracks gas density and enrichment. We find that the average IRX and SSFR follow a galaxy age parameter ξ, which is determined mainly by the galaxy mass and time since formation. We conclude that blue-sequence galaxies have properties which show simple, systematic trends with mass and time such as the steady buildup of heavy elements in the interstellar media of evolving galaxies and the exhaustion of gas in galaxies that are evolving off the blue sequence. The IRX represents a tool for selecting galaxies at various stages of evolution.
|Additional Information:||© 2007 American Astronomical Society. Received 2007 January 21; accepted 2007 July 27. GALEX (Galaxy Evolution Explorer) is a NASA Small Explorer, launched in 2003 April. We gratefully acknowledge NASA’s support for construction, operation, and science analysis for the GALEX mission, developed in cooperation with the Centre National d’Etudes Spatiales of France and the Korean Ministry of Science and Technology. Facilities: GALEX, Sloan|
|Group:||Space Radiation Laboratory|
|Subject Keywords:||galaxies: evolution; ultraviolet: galaxies|
|Official Citation:||D. Christopher Martin et al 2007 ApJS 173 415 doi: 10.1086/522088|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Jason Perez|
|Deposited On:||22 Apr 2010 17:24|
|Last Modified:||04 Mar 2013 18:15|
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