TY - JOUR
T1 - ZFOURGE catalogue of AGN candidates
T2 - An enhancement of 160-μm-derived star formation rates in active galaxies to z = 3.2
AU - Cowley, Michael J.
AU - Spitler, Lee R.
AU - Tran, Kim Vy H.
AU - Rees, Glen A.
AU - Labbé, Ivo
AU - Allen, Rebecca J.
AU - Brammer, Gabriel B.
AU - Glazebrook, Karl
AU - Hopkins, Andrew M.
AU - Juneau, Stéphanie
AU - Kacprzak, Glenn G.
AU - Mullaney, James R.
AU - Nanayakkara, Themiya
AU - Papovich, Casey
AU - Quadri, Ryan F.
AU - Straatman, Caroline M.S.
AU - Tomczak, Adam R.
AU - van Dokkum, Pieter G.
PY - 2016/1/11
Y1 - 2016/1/11
N2 - We investigate active galactic nuclei (AGN) candidates within the FourStar Galaxy Evolution Survey (ZFOURGE) to determine the impact they have on star formation in their host galaxies. We first identify a population of radio, X-ray, and infrared-selected AGN by cross-matching the deep Ks-band imaging of ZFOURGE with overlapping multiwavelength data. From this, we construct a mass-complete (log(M*/M⊙) =9.75), AGN luminosity limited sample of 235 AGN hosts over z = 0.2-3.2. We compare the rest-frame U - V versus V - J (UVJ) colours and specific star formation rates (sSFRs) of the AGN hosts to a mass-matched control sample of inactive (non-AGN) galaxies. UVJ diagnostics reveal AGN tend to be hosted in a lower fraction of quiescent galaxies and a higher fraction of dusty galaxies than the control sample. Using 160 μm Herschel PACS data, we find the mean specific star formation rate of AGN hosts to be elevated by 0.34 ± 0.07 dex with respect to the control sample across all redshifts. This offset is primarily driven by infrared-selected AGN, where the mean sSFR is found to be elevated by as much as a factor of ~5. The remaining population, comprised predominantly of X-ray AGN hosts, is found mostly consistent with inactive galaxies, exhibiting only a marginal elevation. We discuss scenarios that may explain these findings and postulate that AGN are less likely to be a dominant mechanism for moderating galaxy growth via quenching than has previously been suggested.
AB - We investigate active galactic nuclei (AGN) candidates within the FourStar Galaxy Evolution Survey (ZFOURGE) to determine the impact they have on star formation in their host galaxies. We first identify a population of radio, X-ray, and infrared-selected AGN by cross-matching the deep Ks-band imaging of ZFOURGE with overlapping multiwavelength data. From this, we construct a mass-complete (log(M*/M⊙) =9.75), AGN luminosity limited sample of 235 AGN hosts over z = 0.2-3.2. We compare the rest-frame U - V versus V - J (UVJ) colours and specific star formation rates (sSFRs) of the AGN hosts to a mass-matched control sample of inactive (non-AGN) galaxies. UVJ diagnostics reveal AGN tend to be hosted in a lower fraction of quiescent galaxies and a higher fraction of dusty galaxies than the control sample. Using 160 μm Herschel PACS data, we find the mean specific star formation rate of AGN hosts to be elevated by 0.34 ± 0.07 dex with respect to the control sample across all redshifts. This offset is primarily driven by infrared-selected AGN, where the mean sSFR is found to be elevated by as much as a factor of ~5. The remaining population, comprised predominantly of X-ray AGN hosts, is found mostly consistent with inactive galaxies, exhibiting only a marginal elevation. We discuss scenarios that may explain these findings and postulate that AGN are less likely to be a dominant mechanism for moderating galaxy growth via quenching than has previously been suggested.
KW - Galaxies: active
KW - Galaxies: evolution
KW - Galaxies: high-redshift
KW - Infrared: galaxies
KW - Radio continuum: galaxies
KW - X-rays: galaxies
UR - http://www.scopus.com/inward/record.url?scp=84961634171&partnerID=8YFLogxK
UR - http://purl.org/au-research/grants/arc/DP1094370
UR - http://purl.org/au-research/grants/arc/FT140100933
U2 - 10.1093/mnras/stv2992
DO - 10.1093/mnras/stv2992
M3 - Article
AN - SCOPUS:84961634171
SN - 0035-8711
VL - 457
SP - 629
EP - 641
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 1
ER -