Linking Stellar Mass and Star Formation in Spitzer MIPS 24 ?m Galaxies
In: The Astrophysical Journal, Jg. 637 (2006-02-01), Heft 2, S. 727-740
Online
serialPeriodical
Zugriff:
We present deep Ks < 21.5 (Vega) identifications, redshifts, and stellar masses for most of the sources composing the bulk of the 24 mm background in the GOODS/CDFS. Our identified sample consists of 747 Spitzer MIPS 24 mm objects and includes ~94% of all the 24 mm sources in the GOODS-South field that have fluxes Sn(24 mm) > 83 mJy (the ~80% completeness limit of the Spitzer/GTO 24 mm 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 mm 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 mm galaxy population ranges from sources with intermediate luminosities (1010 L < LIR < 1011 L) and low-to-intermediate assembled stellar masses (109 M [?] M [?] 1011 M) at z [?] 0.8, to massive (M [?] 1011 M) hyperluminous galaxies (LIR > 1012 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 [?]1010-1011 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 x 1010 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.
Titel: |
Linking Stellar Mass and Star Formation in Spitzer MIPS 24 ?m Galaxies
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Autor/in / Beteiligte Person: | Floc, Le |
Link: | |
Zeitschrift: | The Astrophysical Journal, Jg. 637 (2006-02-01), Heft 2, S. 727-740 |
Veröffentlichung: | 2006 |
Medientyp: | serialPeriodical |
ISSN: | 0004-637X (print) ; 1538-4357 (print) |
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