Contribution of Lensed SCUBA Galaxies to the Cosmic Infrared Background

TL;DR

This paper uses gravitational lensing of galaxy clusters to estimate the faint end of submillimeter galaxy counts, providing insights into the cosmic infrared background and guiding future sub-mm surveys.

Contribution

It presents the first large catalog-based estimate of faint sub-mm galaxy counts using lensing, constraining the contribution to the cosmic infrared background.

Findings

Estimated the 850 micron number counts down to 0.10 mJy.

Derived a lower limit for the extragalactic far-infrared background.

Results are consistent with FIRAS measurements.

Abstract

The surface density of submillimeter (sub-mm) galaxies as a function of flux, usually termed the source number counts, constrains models of the evolution of the density and luminosity of starburst galaxies. At the faint end of the distribution, direct detection and counting of galaxies are not possible. However, gravitational lensing by clusters of galaxies allows detection of sources which would otherwise be too dim to study. We have used the largest catalog of sub-mm-selected sources along the line of sight to galaxy clusters to estimate the faint end of the 850 micron number counts; integrating to S = 0.10 mJy the equivalent flux density at 850 microns is v I_{v} = 0.24 +/- 0.03 nW/m^2/sr. This provides a lower limit to the extragalactic far-infrared background and is consistent with direct estimates of the full intensity from the FIRAS. The results presented here can help to guide strategies for upcoming surveys carried out with single dish sub-mm instruments.