Fueling Low-Level AGN Activity through Stochastic Accretion of Cold Gas

By P. Hopkins, L. Hernquist. 2006

230 citations recorded by the source corpus.

Using a simple description of feedback from black hole growth, we develop an analytic model for the fueling of Seyferts (low-luminosity active galactic nuclei [AGNs]) and their relation to their host galaxies, Eddington ratio distributions, and cosmological evolution. We derive a solution for the time evolution of accretion rates in a feedback-driven blast wave, applicable to large-scale outflows from bright quasars in galaxy mergers, low-luminosity AGNs, and black holes or neutron stars in supernova remnants. Under the assumption that cold gas stochastically accretes onto a central supermassive black hole at a rate set by the dynamics of that gas, our solution determines the evolution of Seyfert light curves. Using this model, we predict the Seyfert luminosity function, duty cycles and AGN "lifetimes," and the distribution of host morphologies, Eddington ratios, and obscuration as a function of AGN luminosity and black hole mass, and we find agreement with observations at z = 0. We consider the breakdown of the contribution from this mechanism and from stellar wind and virialized hot gas accretion and merger-driven activity. We also make specific predictions for the weak evolution of the Seyfert luminosity function; i.e., luminosity function of quiescent as opposed to merger-driven activity, as a function of redshift, and for changes in both the slope and scatter of the MBH-σ relation at low MBH. Our modeling provides a quantitative and physical distinction between local, low-luminosity quiescent AGN activity and violent, merger-driven bright quasars. In our picture, the quiescent mode of fueling dominates over a wide range of luminosities (-15 ≳ MB ≳ -22) at z = 0, where most black hole growth occurs in objects with MBH ≲ 107 M☉, in S0 and Sa/b galaxies. However, quasar activity from gas-rich mergers evolves more rapidly with redshift, and by z = 1, quiescent fueling is important only at luminosities an order of magnitude or more below the "break" in the luminosity function. Consequently, although non-merger-driven fueling is important for black hole growth and the MBH-σ relation at low MBH, it does not significantly contribute to the black hole mass density of the universe or to cosmological backgrounds.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/41231e7e81e7510294e26404f2e76a94bef0b7ca

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Citations in the corpus

Quasar feedback: more bang for your buck (2009, methodology): “Again, we refer to the full derivation in Hopkins & Hernquist (2006) for details, but the self-consistent solution derived therein can be approximated as L ∝ [1 + t/tQ]−ηL , with ηL ∼ 1.5 and tQ ∼ 1 − 5 × 107 yr for the parameters here (consistent with various observational constraints; see Martini…”
CONSTRAINTS ON BLACK HOLE GROWTH, QUASAR LIFETIMES, AND EDDINGTON RATIO DISTRIBUTIONS FROM THE SDSS BROAD-LINE QUASAR BLACK HOLE MASS FUNCTION (2010, methodology): “In addition, this model predicts that during this so-called blow-out phase, the fuel supply is set by the evolution of the blast wave caused by the injection of energy from the SMBH, and is expected to be of the form Ṁ(t) ∝ t−β (Hopkins & Hernquist 2006; Hopkins et al. 2006b).”
Black Holes in Pseudobulges and Spheroidals: A Change in the Black Hole-Bulge Scaling Relations at Low Mass (2008, background): “If BH growth at low mass is driven by more stochastic processes (e.g., Hopkins & Hernquist 2006), then we might indeed expect to see a bias toward more massive host galaxies at a given BH mass.”
Discriminating Between the Physical Processes that Drive Spheroid Size Evolution (2009, background): “Various works have shown that this can naturally account for the observed correlations between BH mass and spheroid velocity dispersion, mass and other properties (see e.g. Silk & Rees 1998; Di Matteo, Springel & Hernquist 2005; Hopkins & Hernquist 2006; Hopkins et al. 2007a).”
Intermediate mass black holes in AGN discs – I. Production and growth (2012, background): “If a large quantity of gas somehow arrives in the innermost pc of a galactic nucleus (e.g. Krolik 1999; Kawawatu et al. 2003; Vittorini et al. 2005; Hopkins & Hernquist 2006; McKernan et al. 2010b), it will likely lose angular momentum and accrete onto the central supermassive black hole.”
DISSIPATION AND EXTRA LIGHT IN GALACTIC NUCLEI. IV. EVOLUTION IN THE SCALING RELATIONS OF SPHEROIDS (2008, methodology): “Based on our theoretical modeling of selfregulated black hole growth in simulations (Di Matteo et al. 2005; Hopkins et al. 2006a; Hopkins & Hernquist 2006; Hopkins et al. 2007b) and that of others (e.g. Silk & Rees 1998; Murray et al. 2005; Ciotti & Ostriker 2007), essentially any model where the…”
A Log-Quadratic Relation for Predicting Supermassive Black Hole Masses from the Host Bulge Sérsic Index (2006, background): “In passing we note that there have been claims that theMbhrelation may not be linear but may have either negative curvature (e.g., Granato et al. 2004; Cirasuolo et al. 2005), positive curvature (e.g., Hopkins & Hernquist 2006), or no curvature at even the 0.75Y1.”
PRIMUS: THE DEPENDENCE OF AGN ACCRETION ON HOST STELLAR MASS AND COLOR (2011, background): “Alternatively AGN activity could be fed by smooth cosmological cold gas accretion (e.g., Kereš et al. 2005), stochastic accretion of gas within the galaxy (e.g., Hopkins & Hernquist 2006), or mass loss from evolved stars (e.g., Ciotti & Ostriker 2007; Kauffmann & Heckman 2009).”
Black Hole Spin and Galactic Morphology (2007, background): “In the hierarchical framework we might expect that the BH hosted by an elliptical galaxy had, as last major accretion episode, a large increase in its mass following the major merger which created the elliptical itself (Hopkins & Hernquist 2006).”
Radiative Feedback from Massive Black Holes in Elliptical Galaxies: AGN Flaring and Central Starburst Fueled by Recycled Gas (2007, background): “In fact, when addressing galaxy evolution over cosmological times, two main effects have not been considered in the present treatment, namely, galaxy formation itself and the successive cosmological infall and merging events (e.g., Hopkins & Hernquist 2006; Micic et al. 2007).”
An Observational Determination of the Bolometric Quasar Luminosity Function (2006, background): “…by hydrodynamic simulations (Hopkins et al. 2005a, 2005b, 2005d) and analytical models of accretion rate evolution in feedback-driven outflows (Hopkins & Hernquist 2006), which both predict that the faint-end shape should be controlled by the shape of the quasar light curve, itself a function…”
Dissipation and Extra Light in Galactic Nuclei. I. Gas-Rich Merger Remnants (2008, background): “(With the possibility that they could have been modified subsequently in gas-free mergers with other ellipticals that did not trigger quasar activity or lead to black hole growth, and that modest black hole growth can occur with non–merger-induced fueling [Hopkins & Hernquist 2006].)”
A Cosmological Framework for the Co-Evolution of Quasars, Supermassive Black Holes, and Elliptical Galaxies. II. Formation of Red Ellipticals (2007, methodology): “…a number of analytic models that have been proposed for the effects of this feedback, including the blast wave model calibrated to simulations in Hopkins & Hernquist (2006), the model of Scannapieco & Oh (2004) in terms of the postshock entropy, and the temperature/cooling time calculations in…”
A Theoretical Interpretation of the Black Hole Fundamental Plane (2007, background): “More properly, what occurs in our simulations is a pressure-driven outflow from the central regions (e.g., Hopkins et al. 2006b; Hopkins & Hernquist 2006).”
Direct Cosmological Simulations of the Growth of Black Holes and Galaxies (2007, background): “The threshold for this ‘‘blowout’’ phase is determined by the local gas properties and gravitational potential of the host (Hopkins et al. 2006b; Hopkins & Hernquist 2006).”
How do massive black holes get their gas (2009, background): “…principle possible that some molecular clouds could be scattered on to very low angular momentum orbits, but even the optimistic fuelling rates from this process are generally insufficient to produce luminous quasars (see e.g. Hopkins & Hernquist 2006; Nayakshin & King 2007; Kawakatu & Wada 2008).”
MERGERS AND BULGE FORMATION IN ΛCDM: WHICH MERGERS MATTER? (2009, background): “…clearly directly linked to the kinds of mergers triggering activity – one would expect continuous, high-duty cycle but low-level activity from sufficiently minor mergers, with more dramatic, dusty, shorter duty-cycle activity in major mergers (Hopkins & Hernquist 2006, 2009; Hopkins et al. 2009d).”