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Linking stellar mass and star formation in Spitzer/MIPS 24 micron galaxies

K. I. Caputi·H. Dole·G. Lagache·R. J. McLure·J. -L. Puget·G. H. Rieke·J. S. Dunlop·E. Le Floc'h·C. Papovich·P. G. Perez-Gonzalez
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Abstract

We present deep Ks<21.5 (Vega) identifications, redshifts and stellar masses for most of the sources composing the bulk of the 24 micron background in the GOODS/CDFS. Our identified sample consists of 747 Spitzer/MIPS 24 micron objects, and includes ~94% of all the 24 micron sources in the GOODS-South field which have fluxes Snu(24)>83 microJy (the 80% completeness limit of the Spitzer/GTO 24 micron catalog). 36% of our galaxies have spectroscopic redshifts (mostly at z<1.5) and the remaining ones have photometric redshifts of very good quality, with a median of |dz|=|zspec-zphot|/(1+zspec)=0.02. We find that MIPS 24 micron galaxies span the redshift range z~0-4, and that a substantial fraction (28%) lie at high redshifts z>1.5. We determine the existence of a bump in the redshift distribution at z~1.9, indicating the presence of a significant population of galaxies with PAH emission at these redshifts. Massive (M>10^11 Msun) star-forming galaxies at redshifts 2 500 Msun/yr), and some of them are able to construct a mass of 10^10-10^11 Msun in a single burst lifetime (~0.01-0.1 Gyr). At lower redshifts z<2, massive star-forming galaxies are also present, but appear to be building their stars on long timescales, either quiescently or in multiple modest burst-like episodes. At redshifts z~1-2, the ability of the burst-like mode to produce entire galaxies in a single event is limited to some lower (M<7x10^10 Msun) mass systems, and it is basically negligible at z<1. Our results support a scenario where star-formation activity is differential with assembled stellar mass and redshift, and where the relative importance of the burst-like mode proceeds in a down-sizing way from high to low redshifts. (abridged)

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K. I. Caputi, H. Dole, G. Lagache, R. J. McLure, J. -L. Puget, G. H. Rieke, J. S. Dunlop, E. Le Floc'h, C. Papovich, P. G. Perez-Gonzalez. 2005-10-04. Linking stellar mass and star formation in Spitzer/MIPS 24 micron galaxies. https://doi.org/10.1086/498497

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