THE POPULATION OF VISCOSITY- AND GRAVITATIONAL WAVE-DRIVEN SUPERMASSIVE BLACK HOLE BINARIES AMONG LUMINOUS ACTIVE GALACTIC NUCLEI

By Zoltán Haiman, B. Kocsis, Kristen Menou. 2009

174 citations recorded by the source corpus.

Supermassive black hole binaries (SMBHBs) in galactic nuclei are thought to be a common by-product of major galaxy mergers. We use simple disk models for the circumbinary gas and for the binary–disk interaction to follow the orbital decay of SMBHBs with a range of total masses (M) and mass ratios (q), through physically distinct regions of the disk, until gravitational waves (GWs) take over their evolution. Prior to the GW-driven phase, the viscous decay is generically in the stalled “secondary-dominated” regime. SMBHBs spend a non-negligible fraction of a fiducial time of 107 yr at orbital periods between days ≲torb≲ yr, and we argue that they may be sufficiently common to be detectable, provided they are luminous during these stages. A dedicated optical or X-ray survey could identify coalescing SMBHBs statistically, as a population of periodically variable quasars, whose abundance obeys the scaling Nvar ∝ tαvar within a range of periods around tvar∼ tens of weeks. SMBHBs with M ≲ 107 M☉, with 0.5 ≲ α ≲ 1.5, would probe the physics of viscous orbital decay, whereas the detection of a population of higher-mass binaries, with α = 8/3, would confirm that their decay is driven by GWs. The lowest-mass SMBHBs (M ≲ 105–6 M☉) enter the GW-driven regime at short orbital periods, when they are already in the frequency band of the Laser Interferometric Space Antenna (LISA). While viscous processes are negligible in the last few years of coalescence, they could reduce the amplitude of any unresolved background due to near-stationary LISA sources. We discuss modest constraints on the SMBHB population already available from existing data, and the sensitivity and sky coverage requirements for a detection in future surveys. SMBHBs may also be identified from velocity shifts in their spectra; we discuss the expected abundance of SMBHBs as a function of their orbital velocity.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/fc978d72d8b69dcbdf99e7e4b88a959c3dfe4678

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In Astronomy and Astrophysics

1. Zoltán Haiman
2. L. Hernquist
3. B. Metzger
4. E. Barausse
5. P. Hopkins
6. M. Volonteri
7. A. Sesana
8. A. MacFadyen

Citations in the corpus

• Black-hole binaries, gravitational waves, and numerical relativity (2010, background): “…a recoiling merged black hole encountering the disk (Armitage and Natarajan, 2002; Bode and Phinney, 2007; Chang et al., 2009; Dotti et al., 2006; Haiman et al., 2009a,b; Kocsis et al., 2006, 2008; Kocsis and Loeb, 2008; Lippai et al., 2008; Megevand et al., 2009; Milosavljević and Phinney,…”
• Evolution of binary black holes in self gravitating discs. Dissecting the torques (2012, background): “…than the often adopted simple assumption that resonant torques arising at the disc inner edge transfer angular momentum from the BHB to the disc, causing the orbital decay (e.g. Papaloizou & Pringle 1977; Goldreich & Tremaine 1980; Ivanov et al. 1999; Armitage & Natarajan 2002; Haiman et al. 2009).”
• Massive Black Hole Binary Mergers in Dynamical Galactic Environments (2016, background): “Kocsis & Sesana (2011) incorporate viscous drag from a circumbinary gaseous disk (Haiman et al. 2009, hereafter HKM09) on top of halos and mergers from the dark-matter only Millennium simulations (Springel et al. 2005), with MBH added in post-processing.”
• False periodicities in quasar time-domain surveys (2016, background): “They interpreted their discovery in terms of a short-period binary supermassive black hole system (Haiman et al. 2009a).”
• Science with the space-based interferometer eLISA. III: probing the expansion of the universe using gravitational wave standard sirens (2016, background): “Indeed, if sufficient gas is present in the nuclear region, planet-like migration may drive the BH binary to coalescence within ∼ 107−108 yr [60, 61] (although this scenario is not immune from possible complications, see e.”
• Constraining Stellar-mass Black Hole Mergers in AGN Disks Detectable with LIGO (2017, background): “BH binaries that form in the disk are expected to merge efficiently due to gas torques (e.g., Haiman et al. 2009; Stahler 2010; Baruteau et al. 2011; Kocsis et al. 2011; McKernan et al. 2011, 2012).”
• Rapid and Bright Stellar-mass Binary Black Hole Mergers in Active Galactic Nuclei (2016, methodology): “(14) of Haiman et al. (2009), and we thus use Eq.”
• The NANOGrav 11 Year Data Set: Pulsar-timing Constraints on the Stochastic Gravitational-wave Background (2018, background): “…be the case if three-body scattering of stars from the galactic-center loss cone (e.g. Quinlan 1996; Sesana et al. 2006) or interaction with a viscous circumbinary disk (e.g. Kocsis & Sesana 2011; Haiman et al. 2009) are a stronger dynamical influence than GW emission at wide orbital separations.”
• Limiting eccentricity of subparsec massive black hole binaries surrounded by self-gravitating gas discs (2011, methodology): “…in the quadrupole approximation, is given by (Peters & Mathews 1963) tGW = a dt da = 7.84 × 106 yr M7q−1s ã43F (e)−1, (8) 3 We note that equation 26a of Haiman et al. (2009) is an extrapolation of radiation supported α-discs using the Syer & Clarke (1995) solution to the type II migration problem.”
• Accretion into the central cavity of a circumbinary disc (2012, methodology): “…comes from the integration time required to measure the flux variations for MBHBs in the above mass range [for a survey instrument with a sensitivity similar to Large Synoptic Survey Telescope (LSST); Haiman et al. 2009b], and the upper limit comes from the duration of proposed time domain surveys.”
• The quest for dual and binary supermassive black holes: A multi-messenger view (2019, unknown): “The emission properties of the system can be used to construct a consistent model that can be rescaled to search for the much more abundant population of wider binaries (Haiman et al., 2009) – thus not emitting”
• Black hole mergers: can gas discs solve the ‘final parsec’ problem? (2009, background): “More positively, it offers a new way of inferring the presence of a binary through a combination of this result with possible detectable periodic variability (Haiman et al. 2009).”