The properties of 70 μm-selected high-redshift galaxies in the Extended Groth Strip

TL;DR: In this paper, the infrared properties of 43 high-redshift (0.1 35) galaxies were examined and it was shown that large amounts of dust cause heavy obscuration and are responsible for an additional cold emissive component, appearing as a far infrared excess in their SEDs.

Abstract: We examine the infrared properties of 43 high-redshift (0.1 35, and for a large fraction (similar to 50 per cent) the SED turns over into the Rayleigh-Jeans regime at wavelengths longward of 90 mu m. For comparison, we also fit semi-empirical templates based on local galaxy data; however, these underestimate the far-infrared SED shape by a factor of at least 2 and in extreme cases up to 10 for the majority (similar to 70 per cent) of the sources. Further investigation of SED characteristics reveals that the mid-infrared (70/24 mu m) continuum slope is decoupled from various galaxy properties such as the total infrared luminosity and far-infrared peak, quantified by the L-160/L-70 ratio. In view of these results, we propose that these high-redshift galaxies have different properties to their local counterparts, in the sense that large amounts of dust cause heavy obscuration and are responsible for an additional cold emissive component, appearing as a far-infrared excess in their SEDs.