2005/10/04 by K. I. Caputi, H. Dole, G. Lagache +11 · 1 citation
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Galaxies: Formation, Evolution, Phenomena #Galaxy #Gamma-ray bursts and supernovae #Physics #Population #Redshift #Star formation #Stellar mass #astro-ph
paper · pdf · doi:10.1086/498497
published as Astrophys.J.637:727-740,2006 · Accepted for publication in the ApJ. 19 pages, 10 figures. Uses emulateapj
arxiv created 2005/10/04 · openalex publication_date 2006/01/25 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present deep K s < 21.5 (Vega) identifications, redshifts, and stellar masses for most of the sources composing the bulk of the 24 μm background in the GOODS/CDFS. Our identified sample consists of 747 Spitzer MIPS 24 μm objects and includes ~94% of all the 24 μm sources in the GOODS-South field that have fluxes S ν (24 μm) > 83 μJy (the ~80% completeness limit of the Spitzer /GTO 24 μm 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 | = | z spec - z phot |/(1 + z spec ) = 0.02. We find that MIPS 24 μm 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. The 24 μm galaxy population ranges from sources with intermediate luminosities (10 10 L ☉ < L IR < 10 11 L ☉ ) and low-to-intermediate assembled stellar masses (10 9 M ☉ ≲ M ≲ 10 11 M ☉ ) at z ≲ 0.8, to massive ( M ≳ 10 11 M ☉ ) hyperluminous galaxies ( L IR > 10 12 L ☉ ) at redshifts z ~ 2-3. Massive star-forming galaxies at redshifts 2 ≲ z ≲ 3 are characterized by very high star formation rates (SFR > 500 M ☉ yr -1 ), and some of them are able to construct a mass of ≈10 10 -10 11 M ☉ 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 burstlike episodes. At redshifts z ~ 1-2, the ability of the burstlike mode to produce entire galaxies in a single event is limited to some lower ( M ≲ 7 × 10 10 M ☉ ) mass systems, and it is basically negligible at z ≲ 1. Our results support a scenario in which star formation activity is differential with assembled stellar mass and redshift, and where the relative importance of the burstlike mode proceeds in a downsizing way from high to low redshifts.