Tracing the cosmic growth of supermassive black holes to z ∼ 3 with Herschel★

Abstract

We study a sample of Herschel-PACS selected galaxies within the GOODS-South\nand the COSMOS fields in the framework of the PACS Evolutionary Probe (PEP)\nproject. Starting from the rich multi-wavelength photometric data-sets\navailable in both fields, we perform a broad-band Spectral Energy Distribution\n(SED) decomposition to disentangle the possible active galactic nucleus (AGN)\ncontribution from that related to the host galaxy. We find that 37 per cent of\nthe Herschel-selected sample shows signatures of nuclear activity at the 99 per\ncent confidence level. The probability to reveal AGN activity increases for\nbright ($L_{\\rm 1-1000} > 10^{11} \\rm L_{\\odot}$) star-forming galaxies at\n$z>0.3$, becoming about 80 per cent for the brightest ($L_{\\rm 1-1000} >\n10^{12} \\rm L_{\\odot}$) infrared (IR) galaxies at $z \\geq 1$. Finally, we\nreconstruct the AGN bolometric luminosity function and the super-massive black\nhole growth rate across cosmic time up to $z \\sim 3$ from a Far-Infrared (FIR)\nperspective. This work shows general agreement with most of the panchromatic\nestimates from the literature, with the global black hole growth peaking at $z\n\\sim 2$ and reproducing the observed local black hole mass density with\nconsistent values of the radiative efficiency $\\epsilon_{\\rm rad}$\n($\\sim$0.07).\n