Correlated Anisotropies in the Cosmic Far-Infrared Background Detected by MIPS/Spitzer: Constraint on the Bias

TL;DR

This study detects correlated anisotropies in the Cosmic Far-Infrared Background at 160 microns, revealing galaxy clustering at z~1 and providing a bias measurement higher than local IRAS galaxies.

Contribution

First detection of correlated anisotropies in the CFIRB at 160 microns, with a model estimating galaxy bias at z~1, indicating evolution in galaxy clustering.

Findings

Detected strong anisotropies at 5-30 arcminutes scales

Derived galaxy bias of 1.74 ± 0.16 at z~1

Infrared galaxies at high redshift are biased tracers of mass

Abstract

We report the detection of correlated anisotropies in the Cosmic Far-Infrared Background at 160 microns. We measure the power spectrum in the Spitzer/SWIRE Lockman Hole field. It reveals unambiguously a strong excess above cirrus and Poisson contributions, at spatial scales between 5 and 30 arcminutes, interpreted as the signature of infrared galaxy clustering. Using our model of infrared galaxy evolution we derive a linear bias b=1.74 \pm 0.16. It is a factor 2 higher than the bias measured for the local IRAS galaxies. Our model indicates that galaxies dominating the 160 microns correlated anisotropies are at z~1. This implies that infrared galaxies at high redshifts are biased tracers of mass, unlike in the local Universe.