The Herschel PEP/HerMES Luminosity Function. I: Probing the Evolution of PACS selected Galaxies to z~4

Understand

We exploit the deep and extended far infrared data sets (at 70, 100 and 160 um) of the Herschel GTO PACS Evolutionary Probe (PEP) Survey, in combination with the HERschel Multi tiered Extragalactic Survey (HerMES) data at 250, 350 and 500 um, to derive the evolution of the restframe 35 um, 60 um, 90 um, and total infrared (IR) luminosity functions (LFs) up to z~4.

• We detect very strong luminosity evolution for the total IR LF combined with a density evolution.
• In agreement with previous findings, the IR luminosity density increases steeply to z~1, then flattens between z~1 and z~3 to decrease at z greater than 3.
• Galaxies with different SEDs, masses and sSFRs evolve in very different ways and this large and deep statistical sample is the first one allowing us to separately study the different evolutionary behaviours of the individual IR populations contributing to the IR luminosity density.