Spitzer IRAC identification of Herschel-ATLAS SPIRE sources

Abstract

We use spitzer-IRAC data to identify near-infrared counterparts to submillimeter galaxies detected with Herschel-SPIRE at 250um in the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS). Using a likelihood ratio analysis we identify 146 reliable IRAC counterparts to 123 SPIRE sources out of the 159. We find that, compared to the field population, the SPIRE counterparts occupy a distinct region of 3.6 and 4.5um color-magnitude space, and we use this property to identify a further 23 counterparts to 13 SPIRE sources. The IRAC identification rate of 86% is significantly higher than those that have been demonstrated with wide-field ground-based optical and near-IR imaging of Herschel fields. We estimate a false identification rate of 3.6%, corresponding to 4 to 5 sources. Among the 73 counterparts that are undetected in SDSS, 57 have both 3.6 and 4.5um coverage. Of these 43 have [3.6] - [4.5]> 0 indicating that they are likely to be at z > 1.4. Thus, ~ 40% of identified SPIRE galaxies are likely to be high redshift (z > 1.4) sources. We discuss the statistical properties of the IRAC-identified SPIRE galaxy sample including far-IR luminosities, dust temperatures, star-formation rates, and stellar masses. The majority of our detected galaxies have 10^10 to 10^11 L_sun total IR luminosities and are not intense starbursting galaxies as those found at z ~ 2, but they have a factor of 2 to 3 above average specific star-formation rates compared to near-IR selected galaxy samples.

16 pages, 12 figures, two tables. Accepted for publication in ApJ

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Cited by in corpus (8)

• Dusty Star-Forming Galaxies at High Redshift
• The Herschel-ATLAS Data Release 1 Paper II: Multi-wavelength counterparts to submillimetre sources
• Herschel-ATLAS: VISTA VIKING near-IR counterparts in the Phase 1 GAMA 9h data
• Submm/mm Galaxy Counterpart Identification Using a Characteristic Density Distribution
• The Herschel Virgo Cluster Survey. XIX. Physical properties of low luminosity FIR sources at $z<$ 0.5
• Multi-band Optical and Near-infrared Properties of Faint Submillimeter Galaxies with Serendipitous ALMA Detections
• Probabilistic positional association of catalogs of astrophysical sources: the Aspects code
• The XXL Survey. XLI. Radio AGN luminosity functions based on the GMRT $610\mathrm{MHz}$ continuum observations