Coevolution (Or Not) of Supermassive Black Holes and Host Galaxies

Abstract

We review the observed demographics and inferred evolution of supermassive black holes (BHs) found by dynamical modeling of spatially resolved kinematics. Most influential was the discovery of a tight correlation between BH mass and the velocity dispersion of the host-galaxy bulge. It and other correlations led to the belief that BHs and bulges coevolve by regulating each other's growth. New results are now replacing this simple story with a richer and more plausible picture in which BHs correlate differently with different galaxy components. BHs are found in pure-disk galaxies, so classical (elliptical-galaxy-like) bulges are not necessary to grow BHs. But BHs do not correlate with galaxy disks. And any correlations with disk-grown pseudobulges or halo dark matter are so weak as to imply no close coevolution. We suggest that there are four regimes of BH feedback. 1- Local, stochastic feeding of small BHs in mainly bulgeless galaxies involves too little energy to result in coevolution. 2- Global feeding in major, wet galaxy mergers grows giant BHs in short, quasar-like "AGN" events whose feedback does affect galaxies. This makes classical bulges and coreless-rotating ellipticals. 3- At the highest BH masses, maintenance-mode feedback into X-ray gas has the negative effect of helping to keep baryons locked up in hot gas. This happens in giant, core-nonrotating ellipticals. They inherit coevolution magic from smaller progenitors. 4- Independent of any feedback physics, the averaging that results from successive mergers helps to engineer tight BH correlations.Comment: 136 pages, 38 postscript figures, 4 tables; requires cittable.tex, psfig.tex, annrev4K-E.tex; accepted for publication in Volume 51 (2013) of Annual Review of Astronomy and Astrophysics; Supplementary Information will be submitted to arXiv separately in approximately 2013 Jun

The jet feedback mechanism (JFM) in stars, galaxies and clusters

“…There is a large body of literature on feedback processes during the epoch of galaxy formation, including feedback from stars, mainly through supernovae, and from AGN, by radiation and/or jets/outflows (e.g., Cattaneo et al 2009;Alexander & Hickox 2012;Fabian 2012;Kormendy & Ho 2013;Heckman & Best 2014;King & Pounds 2015; Tadhunter 2016 for reviews, and, e.g., Wagner et al 2016;Bongiorno et al 2016;Weinberger et al 2016 for recent papers on the AGN-JFM). In this section I review only the AGN-JFM, and concentrate only on processes that are related to other objects that are reviewed here, in particular to cooling flows in clusters of galaxies.…”

“…Possible similarities between the two different AGN-JFM environments are the properties of the outflows from the AGN, in particular sub-relativistic outflows (e.g., Kormendy & Ho 2013;King & Pounds 2015). In addition to the evidence in the visible and UV bands for slow-massive-wide outflows from AGN discussed in section 4.2 (e.g., Zakamska et al 2016), there are indications in the X-ray band for sub-relativistic and relatively massive outflows from AGN (e.g., Behar et al 2003;Pounds et al 2003;Tombesi et al 2010;Chartas et al 2016).…”

AGN Reverberation Mapping

“…While the more commonly-used forms of these relationships tend to be those derived for black holes with dynamically-modeled black hole masses (e.g., Magorrian et al 1998;Ferrarese & Merritt 2000;Gebhardt et al 2000;Gültekin et al 2009;McConnell & Ma 2013;Kormendy & Ho 2013), the AGN relationships provide a useful counterpoint given the differences between the two samples. In particular, the AGN reverberation sample has a large percentage of latetype, disk-dominated galaxies, whereas the quiescent galaxy sample with dynamical black hole masses is comprised mainly of early-type galaxies.…”

“…Here again, barred galaxies (and galaxies with "disky" bulges) are a source of confusion. While they are seen to be outliers in the quiescent M BH − σ ⋆ relationship (Hu, 2008;Graham et al, 2011;Kormendy & Ho, 2013), there is no such offset seen in the AGN M BH − σ ⋆ relationship (Grier et al, 2013a) unless it is artificially inserted by scaling the black hole masses in those galaxies by a different value (Ho & Kim, 2014). Comparisons between the different assumptions and biases in the AGN M BH − σ ⋆ relationship versus the quiescent galaxy relationship will therefore help to shed light on the underlying causes for such puzzles.…”

“…In general, studies have shown that more massive galaxies host more massive black holes, which is interpreted as a symbiosis between galaxies and black holes in which they grow together and regulate each other's growth. Recent studies have begun to find several galaxies that do not appear to follow this simple scaling relationship, however, and our picture of galaxy and black hole co-evolution throughout the Universe's history is becoming more complicated (see the review by Kormendy & Ho 2013).…”