Enhanced star formation rates in AGN hosts with respect to inactive galaxies from PEP-Herschel observations

By P. Santini, D. Rosario, Lijing Shao, D. Lutz, R. Maiolino, D. M. Alexander, B. Altieri, P. Andreani, H. Aussel, F. E. Bauer and 28 more. 2012

181 citations recorded by the source corpus.

We compare the average star formation (SF) activity in X-ray selected AGN hosts with a mass-matched control sample of inactive galaxies, including both star forming and quiescent sources, in the 0.5 10σ confidence level) in the hosts of luminous AGNs. However, when comparing to star forming galaxies only, AGN hosts are found broadly consistent with the locus of their “main sequence”. We investigate the relative far-IR luminosity distributions of active and inactive galaxies, and find a higher fraction of PACS detected, hence normal and highly star forming systems among AGN hosts. Although different interpretations are possible, we explain our findings as a consequence of a twofold AGN growth path: faint AGNs evolve through secular processes, with instantaneous AGN accretion not tightly linked to the current total SF in the host galaxy, while the luminous AGNs co-evolve with their hosts through periods of enhanced AGN activity and star formation, possibly through major mergers. While an increased SF activity with respect to inactive galaxies of similar mass is expected in the latter, we interpret the modest SF offsets measured in low-LX AGN hosts as either a) generated by non-synchronous accretion and SF histories in a merger scenario or b) due to possible connections between instantaneous SF and accretion that can be induced by smaller scale (non-major merger) mechanisms. Far-IR luminosity distributions favour the latter scenario.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/cb9102ea5fb685c44aa129e9889c964c015bef31

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Citations in the corpus

EVIDENCE FOR WIDE-SPREAD ACTIVE GALACTIC NUCLEUS-DRIVEN OUTFLOWS IN THE MOST MASSIVE z ∼ 1–2 STAR-FORMING GALAXIES (2014, methodology): “…used to derive the M∗ and SFR estimates of our SFGs; see Section 2.1) versus a more detailed decomposition accounting for both stellar and AGN light, Santini et al. (2012) showed that stellar masses for type 2 AGNs are typically well recovered with pure stellar templates (with differences on…”
Accreting supermassive black holes in the COSMOS field and the connection to their host galaxies (2012, background): “However, possible deviations from such behaviour have been reported (Shao et al. 2010; Mullaney et al. 2012; Page et al. 2012; Santini et al. 2012; Trichas et al. 2012).”
The Herschel* PEP/HerMES luminosity function - I. Probing the evolution of PACS selected Galaxies to z ≃ 4 (2013, methodology): “Our results seem to confirm those of Santini et al. (2012), finding evidence of a higher average SF activity in AGN hosts with respect to inactive galaxies and a more pronounced level of SF enhancement in the hosts of luminous AGN (i.e. our AGN1 and AGN2).”
Constraining the properties of AGN host galaxies with spectral energy distribution modelling (2015, methodology): “Far-infrared (FIR) and submm surveys with Herschel for example, measure the mean SFR of AGN hosts via stacking methods and show that AGN, on average, lie on the main sequence star-formation at all redshifts (e.g. Mullaney et al. 2012; Santini et al. 2012; Rosario et al. 2012, 2013).”
The mean star formation rate of X-ray selected active galaxies and its evolution from z~2.5: results from PEP-Herschel (2012, background): “In Santini et al. (2012), we show that this bias is unimportant.”
Morphologies of z ∼ 0.7 AGN host galaxies in CANDELS: no trend of merger incidence with AGN luminosity (2014, methodology): “The stellar masses are derived by fitting the spectral energy distributions (SEDs) of the AGN with a mixture of galaxy and quasi-stellar object (QSO) templates, for a more detailed description of the process, we refer the reader to Santini et al. (2009, 2012).”
Tracing the cosmic growth of supermassive black holes to z ∼ 3 with Herschel (2014, background): “…has not yet been derived, it is currently believed that most luminous AGN (LAGN > 1044 erg s−1) are triggered by major merger events (Netzer 2009; Santini et al. 2012), while their fainter counterparts are fueled through secular processes (Shao et al. 2010; Lutz et al. 2010; Rosario et al.…”
X-shooter reveals powerful outflows in z ∼ 1.5 X-ray selected obscured quasi-stellar objects (2014, background): “…a Lbol is derived from LX and a kbol ∼ 20; (12) Eddington ratio; (13) redshift as measured in this work. tion, accurate estimates of stellar masses, SFR and infrared luminosities (see: B10; Salvato et al. 2011; Lusso et al. 2012; Bongiorno et al. 2012; Santini et al. 2012; Rosario et al. 2012).”
The galaxy stellar mass function at 3.5 ≤z ≤ 7.5 in the CANDELS/UDS, GOODS-South, and HUDF fields (2015, methodology): “…a spectral-fitting technique similar to that used in previous studies (Fontana et al. 2004, 2006; Grazian et al. 2006; Maiolino et al. 2008; and Santini et al. 2012a), and similar to those adopted by other groups in the literature (e.g. Dickinson et al. 2003; Drory et al. 2004; Ilbert et al.…”
THE HIDDEN “AGN MAIN SEQUENCE”: EVIDENCE FOR A UNIVERSAL BLACK HOLE ACCRETION TO STAR FORMATION RATE RATIO SINCE z ∼ 2 PRODUCING AN MBH–M* RELATION (2012, result): “This view is consistent with recent studies of the sSFRs and morphologies of X-ray selected AGN hosts which find that the AGN population is dominated by non-mergers (e.g., Cisternas et al. 2011b; Schawinski et al. 2011; Mullaney et al. 2012; Kocevski et al. 2012; Santini et al. 2012).”
GOODS-HERSCHEL: STAR FORMATION, DUST ATTENUATION, AND THE FIR–RADIO CORRELATION ON THE MAIN SEQUENCE OF STAR-FORMING GALAXIES UP TO z ≃ 4 (2014, result): “A number of recent studies (see, e.g., Mullaney et al. 2012, Santini et al. 2012, Juneau et al. 2013, Rosario et al. 2013) have shown that these AGNs are mostly Type-II obscured AGN and LINERS which have similar star-formation rates as normal (i.e., nonAGN) star-forming and passive galaxies,…”
OBSCURATION-DEPENDENT EVOLUTION OF ACTIVE GALACTIC NUCLEI (2015, background): “Observations show that AGN host galaxies are massive and lie, at least in an average sense, on the main sequence of star-formation (Santini et al. 2012).”
A CANDELS–3D-HST SYNERGY: RESOLVED STAR FORMATION PATTERNS AT 0.7 < z < 1.5 (2013, background): “A possible explanation for this difference may be a tendency for actively star-forming, line-emitting galaxies to more frequently host AGN activity (e.g., Santini et al. 2012; Trump et al. 2013).”
STELLAR MASSES FROM THE CANDELS SURVEY: THE GOODS-SOUTH AND UDS FIELDS (2014, methodology): “This median was computed for each galaxy by considering all sets of stellar masses after rescaling them to the same Chabrier IMF (as this is the IMF adopted by all but two of the teams): following Santini et al. (2012a), we subtract 0.24 dex from stellar masses computed assuming the Salpeter IMF.”
BLACK HOLE VARIABILITY AND THE STAR FORMATION–ACTIVE GALACTIC NUCLEUS CONNECTION: DO ALL STAR-FORMING GALAXIES HOST AN ACTIVE GALACTIC NUCLEUS? (2013, background): “…and redshift (e.g., Xue et al. 2010; Cardamone et al. 2010; Bongiorno et al. 2012; Hainline et al. 2012; Rosario et al. 2013a), although they do appear to show slightly stronger and more centrally-concentrated SF (Santini et al. 2012; Rosario et al. 2013b; LaMassa et al. 2013; Hicks et al. 2013).”
The evolution of the dust and gas content in galaxies (2013, methodology): “…we remove all known AGNs from the catalogues (∼2.5% of the total final sample), by considering X-ray detected sources (the AGN sample of Santini et al. 2012b), highly obscured AGNs detected through their mid-IR (MIR) excess (following Fiore et al. 2008), and IRAC selected AGNs (Donley…”