Limiting eccentricity of subparsec massive black hole binaries surrounded by self-gravitating gas discs

By C. Roedig, M. Dotti, A. Sesana, J. Cuadra, M. Colpi. 2011

154 citations recorded by the source corpus.

We study the dynamics of supermassive black hole binaries embedded in circumbinary gaseous discs, with the SPH code GADGET-2. The sub-parsec binary (of total mass M and mass ratio q = 1/3) has excavated a gap and transfers its angular momentum to the self‐ gravitating disc (Mdisc = 0.2M ). We explore the changes of the binary eccentricity e, by simulating a sequence of binary models that differ in the initial eccentricity e0, only. In initially low-eccentric binaries, the eccentricity increase s with time, while in high-eccentric binaries e declines, indicating the existence of a limiting eccentric ity ecrit that is found to fall in the interval [0.6,0.8]. We also present an analytical interpretation for this satu ration limit. An important consequence of the existence of ecrit is the detectability of a significant residual eccentricity eLISA by the proposed gravitational wave detector LISA. It is found that at the moment of entering the LISA frequency domain eLISA � 10 3 10 2 ; a signature of its earlier coupling with the massive circumbinary disc. We also observe large periodic inflows across the gap, occurring on the binary and disc dynamical time scales rather than on the viscous time. These periodic changes in the accretion rate (with amplitudes up to � 100%, depending on the binary eccentricity) can be considered a fin gerprint of eccentric sub-parsec binaries migrating inside a circumbinary disc.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/8f127594bb35aa040bcfe0c6654c97e9824b8779

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Citations in the corpus

The quest for dual and binary supermassive black holes: A multi-messenger view (2019, background): “tionally, accretion occurs preferentially onto the smaller of the two SMBHs, which orbits closer to the inner edge of the circumbinary disk (Artymowicz and Lubow, 1994; Günther and Kley, 2002; Hayasaki et al., 2007a; Roedig et al., 2011; Farris et al., 2014).”
The European Pulsar Timing Array and the Large European Array for Pulsars (2013, background): “…to this issue), in particular the amount of signal damping that might be expected because of star/gas dominated SMBHB evolution (Sesana 2010, Kocsis and Sesana 2011) as well as the change in the spectral shape imprinted by substantially eccentric systems (Sesana 2010, Roedig et al 2011).”
Assisted inspirals of stellar mass black holes embedded in AGN discs: solving the ‘final au problem’ (2016, methodology): “Snapshots of the disk c© 0000 RAS, MNRAS 000, 000–000 torques have been measured in a few of the above simulations, and suggest that the orbital decay is efficient (MacFadyen & Milosavljević 2008; Cuadra et al. 2009; Roedig et al. 2011; D’Orazio, Haiman & MacFadyen 2013).”
The NANOGrav 11 Year Data Set: Pulsar-timing Constraints on the Stochastic Gravitational-wave Background (2018, background): “…et al. 2009; Kocsis & Sesana 2011); (iii) eccentricity, which increases the rate of binary evolution (Peters & Mathews 1963; Peters 1964) and can be amplified by (i) (Sesana et al. 2006; Sesana 2010; Roedig & Sesana 2012) and (ii) (Armitage & Natarajan 2005; Cuadra et al. 2009; Roedig et al. 2011).”
BINARY BLACK HOLE ACCRETION FROM A CIRCUMBINARY DISK: GAS DYNAMICS INSIDE THE CENTRAL CAVITY (2013, result): “Similar results have been found previously in SPH calculations (Hayasaki et al. 2007; Cuadra et al. 2009; Roedig et al. 2011, 2012).”
Evolution of binary black holes in self gravitating discs. Dissecting the torques (2012, methodology): “Whereas, assuming a constant eccentricity growth rate, the limiting value predicted by Roedig et al. (2011) would be reached in less than ∼ 1000P0.”
Accretion into the central cavity of a circumbinary disc (2012, methodology): “Similar overdense lumps have also been found and described in the 3D MHD simulations of Shi et al. (2012); more recently, Roedig et al. (2011, 2012) have also mentioned the contributions of such lumps to fluctuations in the accretion rate.”
The astrophysics of nanohertz gravitational waves (2018, methodology): “For a good introductory review on methods to detect the stochastic background, we refer readers to Romano and Cornish (2017).”