Herschel-ATLAS: Dust temperature and redshift distribution of SPIRE and PACS detected sources using submillimetre colours

TL;DR

This study uses Herschel-ATLAS data to analyze the dust temperature and redshift distribution of far-infrared sources through colour-colour diagrams and spectral energy distribution fitting, revealing typical dust temperatures around 28K and an average redshift near 2.2.

Contribution

It introduces a method to estimate redshift distribution of FIR sources using colour-colour diagrams and SED modeling, extending analysis to sources without known redshifts.

Findings

Average dust temperature of 28K for a bright subsample.

Estimated redshift distribution peaks around 2.2.

Method to infer redshifts from FIR colours for sources lacking spectroscopic data.

Abstract

We present colour-colour diagrams of detected sources in the Herschel-ATLAS Science Demonstration Field from 100 to 500 microns using both PACS and SPIRE. We fit isothermal modified black bodies to the spectral energy distribution (SED) to extract the dust temperature of sources with counterparts in Galaxy And Mass Assembly (GAMA) or SDSS surveys with either a spectroscopic or a photometric redshift. For a subsample of 330 sources detected in at least three FIR bands with a significance greater than 3 $\sigma$, we find an average dust temperature of $(28 \pm 8)$K. For sources with no known redshift, we populate the colour-colour diagram with a large number of SEDs generated with a broad range of dust temperatures and emissivity parameters, and compare to colours of observed sources to establish the redshift distribution of this sample. For another subsample of 1686 sources with fluxes above 35 mJy at 350 microns and detected at 250 and 500 microns with a significance greater than 3$\sigma$, we find an average redshift of $2.2 \pm 0.6$.