Radio and mid-infrared identification of BLAST source counterparts in the Chandra Deep Field South

TL;DR

This study identifies and characterizes BLAST sources in the Chandra Deep Field South using radio and mid-infrared data, revealing their redshift distribution, dust temperatures, and star formation rates, and providing a comprehensive multi-wavelength catalog.

Contribution

It presents the first extensive multi-wavelength identification and analysis of BLAST sources in the CDFS, including redshifts, SED fitting, and insights into dust temperature evolution.

Findings

BLAST sources are at lower redshifts than 850 um submm sources.

Dust temperatures are lower compared to high-redshift submm sources.

Selection effects influence observed dust temperature-redshift relations.

Abstract

We have identified radio and/or mid-infrared counterparts to 198 out of 350 sources detected at >=5 sigma over ~ 9 square degrees centered on the Chandra Deep Field South (CDFS) by the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) at 250, 350 and 500 um. We have matched 114 of these counterparts to optical sources with previously derived photometric redshifts and fitted SEDs to the BLAST fluxes and fluxes at 70 and 160 um acquired with the Spitzer Space Telescope. In this way, we have constrained dust temperatures, total far-infrared/sub-millimeter luminosities and star formation rates for each source. Our findings show that on average, the BLAST sources lie at significantly lower redshifts and have significantly lower rest-frame dust temperatures compared to submm sources detected in surveys conducted at 850 um. We demonstrate that an apparent increase in dust temperature with redshift in our sample arises as a result of selection effects. Finally, we provide the full multi-wavelength catalog of >= 5 sigma BLAST sources contained within the complete ~ 9 square degree survey area.