THE MOSDEF SURVEY: AGN MULTI-WAVELENGTH IDENTIFICATION, SELECTION BIASES, AND HOST GALAXY PROPERTIES

Mojegan Azadi,Sedona H Price,Ryan L Sanders,Brian Siana,Alison L Coil,James Aird,Naveen Reddy,Gene C K Leung,Irene Shivaei,Bahram Mobasher,Mariska Kriek,William R Freeman,Alice Shapley

doi:10.3847/1538-4357/835/1/27

Abstract

ABSTRACT We present results from the MOSFIRE Deep Evolution Field (MOSDEF) survey on the identification, selection biases, and host galaxy properties of 55 X-ray, IR, and optically selected active galactic nuclei (AGNs) at . We obtain rest-frame optical spectra of galaxies and AGNs and use the BPT diagram to identify optical AGNs. We examine the uniqueness and overlap of the AGNs identified at different wavelengths. There is a strong bias against identifying AGNs at any wavelength in low-mass galaxies, and an additional bias against identifying IR AGNs in the most massive galaxies. AGN hosts span a wide range of star formation rates (SFRs), similar to inactive galaxies once stellar mass selection effects are accounted for. However, we find (at ∼2–3σ significance) that IR AGNs are in less dusty galaxies with relatively higher SFR and optical AGNs in dusty galaxies with relatively lower SFR. X-ray AGN selection does not display a bias with host galaxy SFR. These results are consistent with those from larger studies at lower redshifts. Within star-forming galaxies, once selection biases are accounted for, we find AGNs in galaxies with similar physical properties as inactive galaxies, with no evidence for AGN activity in particular types of galaxies. This is consistent with AGNs being fueled stochastically in any star-forming host galaxy. We do not detect a significant correlation between SFR and AGN luminosity for individual AGN hosts, which may indicate the timescale difference between the growth of galaxies and their supermassive black holes.

Highlights

Active galactic nuclei (AGNs) are the result of accretion of gas and dust onto the supermassive black holes (SMBHs) at the centers of galaxies, and have been investigated in numerous studies over the past two decades
We find that the star formation rates (SFRs) and stellar masses estimated from FAST without the template error function after subtracting power-laws are consistent with those derived from the original photometry using the template error function; this indicates our method for estimating SFR and stellar mass is robust
We identify 55 AGNs using the X-ray imaging data from Chandra, MIR data from Infrared Array Camera (IRAC) camera on Spitzer, and rest-frame optical spectra from the MOSFIRE Deep Evolution Field (MOSDEF) survey

Summary

Introduction

Active galactic nuclei (AGNs) are the result of accretion of gas and dust onto the supermassive black holes (SMBHs) at the centers of galaxies, and have been investigated in numerous studies over the past two decades (for a recent review of black hole growth see Alexander & Hickox 2012). The similar evolution of the SMBH accretion rate density and star formation rate (SFR) density with redshift indicates a global connection between AGN activity and the formation of stars in galaxies (e.g., Boyle & Terlevich 1998; Silverman et al 2008; Aird et al 2010; Assef et al 2011). Different studies have used emission at one or more of these wavelengths to identify AGNs and subsequently investigate the nature of their host galaxies (e.g., Kauffmann et al 2003; Goulding & Alexander 2009; Kauffmann & Heckman 2009; Aird et al 2012; Mendez et al 2013; Azadi et al 2015; Cowley et al 2016; Harrison et al 2016)

Results

Discussion

Conclusion