Linking stellar mass and star formation in Spitzer/MIPS 24 micron galaxies
Preprint
- 4 October 2005
Abstract
We present deep Ks83 microJy (the 80% completeness limit of the Spitzer/GTO 24 micron catalog). 36% of our galaxies have spectroscopic redshifts (mostly at z1.5. 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<z500 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)Keywords
All Related Versions
- Version 1, 2005-10-04, ArXiv
- Published version: The Astrophysical Journal, 637 (2), 727.
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