Black Holes in Galaxy Mergers: Evolution of Quasars

By P. Hopkins, L. Hernquist, Thomas J. Cox, T. Di Matteo, P. Martini, Brant Robertson, Volker Springel. 2005

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Based on numerical simulations of gas-rich galaxy mergers, we discuss a model in which quasar activity is tied to the self-regulated growth of supermassive black holes in galaxies. The nuclear inflow of gas attending a galaxy collision triggers a starburst and feeds black hole growth, but for most of the duration of the starburst, the black hole is "buried," being heavily obscured by surrounding gas and dust, limiting the visibility of the quasar, especially at optical and ultraviolet wavelengths. As the black hole grows, feedback energy from accretion heats the gas and eventually expels it in a powerful wind, leaving behind a "dead quasar." Between the buried and dead phases, there is a window in time during which the galaxy would be seen as a luminous quasar. Because the black hole mass, radiative output, and distribution of obscuring gas and dust all evolve strongly with time, the duration of this phase of observable quasar activity depends on both the waveband and imposed luminosity threshold. We determine the observed and intrinsic lifetimes as a function of luminosity and frequency, and calculate observable lifetimes ~10 Myr for bright quasars in the optical B band, in good agreement with empirical estimates and much smaller than our estimated black hole growth timescales ~100 Myr, naturally producing a substantial population of buried quasars. However, the observed and intrinsic energy outputs converge in the IR and hard X-ray bands as attenuation becomes weaker and chances of observation greatly increase. We also obtain the distribution of column densities along sight lines in which the quasar is seen above a given luminosity, and find that our result agrees remarkably well with observed estimates of the column density distribution from the SDSS for the appropriate luminosity thresholds. Our model reproduces a wide range of quasar phenomena, including observed quasar lifetimes, intrinsic lifetimes, column density distributions, and differences between optical and X-ray samples, having properties consistent with observations across more than 5 orders of magnitude in bolometric luminosity from 109 to 1014 L☉ (-17 ≲ MB ≲ -30).

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/d4ae3c5377e036c52f25bb12cc47bdfbc4bc7a32

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Citations in the corpus

A Cosmological Framework for the Co-Evolution of Quasars, Supermassive Black Holes, and Elliptical Galaxies. II. Formation of Red Ellipticals (2007, background): “Because the simulation also includes gas, we can self-consistently integrate along the line of sight to all star particles and calculate the appropriate dust reddening and extinction, following Hopkins et al. (2005).”
Fast outflows in compact radio sources: evidence for AGN-induced feedback in the early stages of radio source evolution (2008, methodology): “…analyses by, for example, Silk & Rees (1998) and Fabian (1999), and more recently, simulations by, for example, Di Matteo et al. (2005) and Hopkins et al. (2005), describe how, after relocating to the centre of the galaxy remnant after a merger (Heckman et al. 1986), the supermassive…”
Stellar and Quasar Feedback in Concert: Effects on AGN Accretion, Obscuration, and Outflows (2015, background): “…are ηP ≡ ṗBAL L/c = β ( vBAL r c ) ≈ β ( vBAL 30,000kms−1 ) (A1) ηE ≡ ĖBAL L = r 2 η2P β ≈ 0.05β ( vBAL 30,000kms−1 )2 (A2) Note for ηP = β = 1, we recover the canonical ηE ≈ 0.05 adopted in previous simulations with purely thermal AGN feedback (e.g. Di Matteo et al. 2005; Hopkins et al. 2005d).”
Dissipation and Extra Light in Galactic Nuclei. I. Gas-Rich Merger Remnants (2008, methodology): “Unlike Figure 19, which was just a qualitative illustration, we include dust obscuration by calculating the column densities through the gas in our simulations in the manner of Hopkins et al. (2005a, 2005b).”
Formation of z~6 Quasars from Hierarchical Galaxy Mergers (2006, methodology): “…(Cox et al. 2006b), the fundamental plane (Robertson et al. 2006a), quasar properties (Hopkins et al. 2005a, 2005d), luminosity functions (Hopkins et al. 2005b, 2005c, 2006b), populations (Hopkins et al. 2006a, 2006d, 2007b), and the luminosity function of low-level AGNs (Hopkins &…”
The DEEP2 galaxy redshift survey: evolution of the colour–density relation at 0.4 < z < 1.35 (2006, background): “…and at least temporarily halt star formation as well as disrupt galactic disks, yielding merger remnants with surface–brightness profiles and density distributions similar to those of early– type galaxies (Toomre & Toomre 1972; Navarro et al. 1987; Barnes & Hernquist 1992; Hopkins et al. 2005).”
An Observational Determination of the Bolometric Quasar Luminosity Function (2006, methodology): “Feedback may also explain trends in obscuration with luminosity, through either dust sublimation (e.g., Lawrence 1991) or expulsion of gas and dust on galactic scales (e.g., Hopkins et al. 2005c).”
THREE-DIMENSIONAL SIMULATIONS OF DYNAMICS OF ACCRETION FLOWS IRRADIATED BY A QUASAR (2007, background): “…of matter not only in their vicinity but also on larger, galactic and even intergalactic scales (Ciotti & Ostriker, 1997, 2001; King 2003; Murray, Quataert, & Thompson 2005; Sazonov et al. 2005; Springel, Di Matteo & Hernquist 2005; Hopkins et al. 2005; Wang, Chen, & Hu and references therein).”
The Evolution of the MBH-σ Relation (2005, background): “Importantly, Hopkins et al. (2005a, 2005b, 2005c, 2005d, 2006a, 2006b, 2006c) calculated a wide range of implications of the co-evolution of spheroids and black holes for the interpretation of both quasar and galaxy observations.”
He ii REIONIZATION AND ITS EFFECT ON THE INTERGALACTIC MEDIUM (2008, methodology): “QSO Method II Recently, simulations of merging galaxies have been used to predict quasar light curves (Hopkins et al. 2005, 2006), and these predictions have been remarkably successful at reconciling observations of the quasar luminosity function, quasar clustering, and the unresolved X-ray…”
COLOR–MAGNITUDE RELATIONS OF ACTIVE AND NON-ACTIVE GALAXIES IN THE CHANDRA DEEP FIELDS: HIGH-REDSHIFT CONSTRAINTS AND STELLAR-MASS SELECTION EFFECTS (2010, background): “In the “radiative mode”, the initially shrouded luminous AGN expels the obscuring gas (that feeds both the SMBH and star formation) and thus quenches star formation (e.g., Hopkins et al. 2005; Springel et al. 2005).”
Testing the evolutionary link between submillimetre galaxies and quasars: CO observations of QSOs at z∼ 2 (2008, background): “This hypothesis has found support from hydrodynamical simulations of galaxy formation, which use feedback from winds and outflows from active galactic nuclei (AGN) to link the growth of the SMBH to that of its host (e.g. Di Matteo, Springel & Hernquist 2005; Hopkins et al. 2005; Bower et al. 2006).”
NUMERICAL SIMULATION OF HOT ACCRETION FLOWS. II. NATURE, ORIGIN, AND PROPERTIES OF OUTFLOWS AND THEIR POSSIBLE OBSERVATIONAL APPLICATIONS (2012, background): “One important reason is because it is believed that AGNs feedback plays an important role in galaxy formation and evolution (e.g., Di Matteo et al. 2005; Hopkins et al. 2005; Fabian 2012).”
Gemini Near-Infrared Spectroscopy of Luminous z ∼ 6 Quasars: Chemical Abundances, Black Hole Masses, and Mg II Absorption (2007, background): “…and the formation processes of galaxies and supermassive black holes (BHs) are closely correlated (e.g., Kauffmann & Haehnelt 2000;Wyithe&Loeb 2003; Hopkins et al. 2005; Croton et al. 2006), so these z 6 objects are essential for studying the accretion history of BHs, galaxy formation, and…”
DISCOVERY OF AN ACTIVE GALACTIC NUCLEUS DRIVEN MOLECULAR OUTFLOW IN THE LOCAL EARLY-TYPE GALAXY NGC 1266 (2011, background): “…including the migration of galaxies from the blue cloud to the red sequence (Faber et al. 2007), merger-driven starbursts and quasar activity (Hopkins et al. 2005), feedback from star formation and central supermassive black holes on the interstellar medium (ISM) (Di Matteo et al. 2005) and…”
Forming disc galaxies in ΛCDM simulations (2006, background): “We speculate that another type of feedback, possibly from an active QSO at the bulge centre (Di Matteo et al. 2005; Hopkins et al. 2005), would decrease SF in the centre and lower the central gas density, reducing the relative weight of the central baryonic concentration.”
A NEW DIAGNOSTIC OF ACTIVE GALACTIC NUCLEI: REVEALING HIGHLY ABSORBED SYSTEMS AT REDSHIFT >0.3 (2011, background): “They are also of interest to test evolutionary scenarios where galaxy major mergers are invoked as a mechanism to form quasars, through a deeply-embedded and absorbed phase (Sanders et al. 1988; Fabian 1999; Hopkins et al. 2005).”