The Evolution of the Star Formation Rate of Galaxies at 0.0 <= z <= 1.2

Citation:

Rujopakarn W, Eisenstein DJ, Rieke GH, Papovich C, Cool RJ, Moustakas J, Jannuzi BT, Kochanek CS, Rieke MJ, Dey A, et al. The Evolution of the Star Formation Rate of Galaxies at 0.0 <= z <= 1.2. The Astrophysical Journal. 2010;718 :1171-1185.

Date Published:

August 1, 2010

Abstract:

We present the 24 μm rest-frame luminosity function (LF) ofstar-forming galaxies in the redshift range 0.0 <= z <= 0.6constructed from 4047 spectroscopic redshifts from the AGN and GalaxyEvolution Survey of 24 μm selected sources in the Boötes fieldof the NOAO Deep Wide-Field Survey. This sample provides the bestavailable combination of large area (9 deg2), depth, andstatistically complete spectroscopic observations, allowing us to probethe evolution of the 24 μm LF of galaxies at low and intermediateredshifts while minimizing the effects of cosmic variance. In order touse the observed 24 μm luminosity as a tracer for star formation,active galactic nuclei (AGNs) that could contribute significantly at 24μm are identified and excluded from our star-forming galaxy samplebased on their mid-IR spectral energy distributions or the detection ofX-ray emission. Optical emission line diagnostics are considered for AGNidentification, but we find that 24 μm emission from opticallyselected AGNs is usually from star-forming activity and therefore shouldnot be excluded. The evolution of the 24 μm LF of star-forminggalaxies for redshifts of z <= 0.65 is consistent with a pureluminosity evolution where the characteristic 24 μm luminosityevolves as (1 + z)3.8±0.3. We extend our evolutionarystudy to encompass 0.0 <= z <= 1.2 by combining our data with thatof the Far-Infrared Deep Extragalactic Legacy Survey. Over this entireredshift range, the evolution of the characteristic 24 μm luminosityis described by a slightly shallower power law of (1 +z)3.4±0.2. We find a local star formation rate densityof (1.09 ± 0.21) × 10-2 M sunyr-1 Mpc-3, and that it evolves as (1 +z)3.5±0.2 over 0.0 <= z <= 1.2. These estimatesare in good agreement with the rates using optical and UV fluxescorrected for the effects of intrinsic extinction in the observedsources. This agreement confirms that star formation at z <~ 1.2 isrobustly traced by 24 μm observations and that it largely occurs inobscured regions of galaxies.

Notes:

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