Evidence for a Population of High-Redshift Submillimeter Galaxies from Interferometric Imaging

Abstract

We have used the Submillimeter Array to image a flux limited sample of seven submillimeter galaxies, selected by the AzTEC camera on the JCMT at 1.1 mm, in the COSMOS field at 890um with 2" resolution. All of the sources - two radio-bright and five radio-dim - are detected as single point-sources at high significance (> 6σ), with positions accurate to 0.2" that enable counterpart identification at other wavelengths observed with similarly high angular resolution. All seven have IRAC counterparts, but only two have secure counterparts in deep HST/ACS imaging. As compared to the two radio-bright sources in the sample, and those in previous studies, the five radio-dim sources in the sample (1) have systematically higher submillimeter-to-radio flux ratios, (2) have lower IRAC 3.6-8.0um fluxes, and (3) are not detected at 24um. These properties, combined with size constraints at 890um (θ< 1.2"), suggest that the radio-dim submillimeter galaxies represent a population of very dusty starbursts, with physical scales similar to local ultraluminous infrared galaxies, and an average redshift higher than radio-bright sources.

7 pages, 3 figures, accepted for publication in ApJ

References in corpus (4)

• The Cosmic Evolution Survey (COSMOS): Subaru Observations of the HST COSMOS Field
• The VLA-COSMOS Survey: II. Source Catalog of the Large Project
• The SCUBA HAlf Degree Extragalactic Survey (SHADES) - III. Identification of radio and mid-infrared counterparts to submillimetre galaxies
• The SCUBA HAlf Degree Extragalactic Survey (SHADES) - IV: Radio-mm-FIR photometric redshifts

Cited by in corpus (21)

• AzTEC Millimetre Survey of the COSMOS Field: I. Data Reduction and Source Catalogue
• Spectroscopic Confirmation Of An Extreme Starburst At Redshift 4.547
• A submillimetre galaxy at z=4.76 in the LABOCA survey of the Extended Chandra Deep Field South
• The Physical Scale of the Far-Infrared Emission in the Most Luminous Submillimeter Galaxies
• A new model for infrared and submillimetre counts
• A 1200-micron MAMBO survey of the GOODS-N field: a significant population of submillimetre drop-out galaxies
• GOODS 850-5 -- A z>4 Galaxy Discovered in the Submillimeter?
• Interferometric imaging of the high-redshift radio galaxy, 4C60.07: An SMA, Spitzer and VLA study reveals a binary AGN/starburst
• The SCUBA Half-Degree Extragalactic Survey (SHADES) - VIII. The Nature of Faint Submm Galaxies in SHADES, SWIRE and SXDF Surveys
• Ultradeep Near-Infrared Observations of GOODS 850-5
• AzTEC Millimetre Survey of the COSMOS Field - II. Source Count Overdensity and Correlations with Large-Scale Structure
• Spitzer IRAC Infrared Colours of Submillimetre-bright Galaxies
• Interferometric detections of GOODS 850-5 at 1 mm and 1.4 GHz
• The merger-driven evolution of warm infrared luminous galaxies
• A Millimetre Survey of Starburst Dominated Ultraluminous Infrared Galaxies at z~2
• Radio and mid-infrared identification of BLAST source counterparts in the Chandra Deep Field South
• Molecular Gas in the z=1.2 Ultraluminous Merger GOODS J123634.53+621241.3
• Clarifying the nature of the brightest submillimetre sources: interferometric imaging of LH850.02
• A close relationship at z~2: submillimetre galaxies and BzK-selected galaxies
• Radio and X-ray properties of submillimeter galaxies in the A2125 field
• An EVLA search for water megamaser emission in the submm galaxy SMM J16359+6612 at z=2.5