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

I Delvecchio,V Mainieri,J Fritz,C Vignali,M Vaccari,S Berta,G Cresci,M Carollo,B Magnelli,M Scodeggio,C Gruppioni,P Popesso,T Contini,A Renzini,G Zamorani,D Scott,S Oliver,A Cimatti,D Lutz,F Pozzi,Anna Feltre ,Asantha Cooray ,E Le Floc’h ,O Le Fèvre ,J J Bock ,S J Lilly

doi:10.1093/mnras/stu130

Abstract

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

Highlights

For more than five decades, since the discovery of quasars, there has been an increasing interest in understanding such extremely bright objects
Though the detailed mechanisms that are the source of the powerful nuclear activity are still debated (Rees 1978; Lodato & Natarajan 2007; Devecchi & Volonteri 2009; Volonteri & Begelman 2010; Ball et al 2011; Natarajan 2011), it is believed that it is mainly due to mass accretion on to a supermassive black hole (SMBH; Salpeter 1964; Lynden-Bell 1969; Shakura & Sunyaev 1973; Soltan 1982; Rees 1984), allowing them to be revealed as active galactic nuclei (AGN)
We found the selection wavelength being poorly related to AGN activity, since its energy contribution to the total energy emitted at 160 μm is negligible (

Summary

Introduction

For more than five decades, since the discovery of quasars, there has been an increasing interest in understanding such extremely bright objects. In the last few years, several studies have highlighted the importance of AGN in the framework of galaxy formation and evolution. A similar anti-hierarchical growth seems to be mirrored in the evolution of the cosmic star formation density (SFD; Cowie et al 1996, 1997; Lilly et al 1996; Madau et al 1996; Bell et al 2005; Juneau et al 2005; Bundy et al 2006; Wall, Pope & Scott 2008; Gruppioni et al 2013), hinting at a deep interplay among the AGN and its host

Objectives

Methods

Findings

Conclusion