The deepest Herschel-PACS far-infrared survey: number counts and infrared luminosity functions from combined PEP/GOODS-H observations

TL;DR

This paper presents the deepest Herschel-PACS far-infrared survey of GOODS fields, providing detailed source catalogs, resolving most of the infrared background, and deriving galaxy luminosity functions up to z~2, advancing understanding of galaxy evolution.

Contribution

It offers the deepest PACS far-infrared observations with new source catalogs, refined luminosity functions, and insights into galaxy evolution, surpassing previous mid-infrared based estimates.

Findings

Resolved ~75% of the cosmic infrared background at 100 and 160 um.

Derived infrared luminosity functions down to LIR=10^11 Lsun at z~1 and LIR=10^12 Lsun at z~2.

Provided publicly available maps and source catalogs for the community.

Abstract

We present results from the deepest Herschel-PACS (Photodetector Array Camera and Spectrometer) far-infrared blank field extragalactic survey, obtained by combining observations of the GOODS (Great Observatories Origins Deep Survey) fields from the PACS Evolutionary Probe (PEP) and GOODS-Herschel key programmes. We describe data reduction and the construction of images and catalogues. In the deepest parts of the GOODS-S field, the catalogues reach 3-sigma depths of 0.9, 0.6 and 1.3 mJy at 70, 100 and 160 um, respectively, and resolve ~75% of the cosmic infrared background at 100um and 160um into individually detected sources. We use these data to estimate the PACS confusion noise, to derive the PACS number counts down to unprecedented depths and to determine the infrared luminosity function of galaxies down to LIR=10^11 Lsun at z~1 and LIR=10^12 Lsun at z~2, respectively. For the infrared luminosity function of galaxies, our deep Herschel far-infrared observations are fundamental because they provide more accurate infrared luminosity estimates than those previously obtained from mid-infrared observations. Maps and source catalogues (>3-sigma) are now publicly released. Combined with the large wealth of multi-wavelength data available for the GOODS fields, these data provide a powerful new tool for studying galaxy evolution over a broad range of redshifts.