scholarly journals The Bardeen–Petterson effect in accreting supermassive black hole binaries: a systematic approach

2020 ◽  
Vol 496 (3) ◽  
pp. 3060-3075 ◽  
Author(s):  
Davide Gerosa ◽  
Giovanni Rosotti ◽  
Riccardo Barbieri
Keyword(s):  
Black Hole ◽  
Systematic Investigation ◽  
Stationary Solutions ◽  
Evolutionary Stage ◽  
Black Hole Binaries ◽  
Frame Dragging ◽  
Supermassive Black Hole ◽  
Complete Alignment ◽  
Hydrodynamical Simulations ◽  
The Impact

ABSTRACT Disc-driven migration is a key evolutionary stage of supermassive black hole binaries hosted in gas-rich galaxies. Besides promoting the inspiral, viscous interactions tend to align the spins of the black holes with the orbital angular momentum of the disc. We present a critical and systematic investigation of this problem, also known as the Bardeen–Petterson effect. We design a new iterative scheme to solve the non-linear dynamics of warped accretion discs under the influence of both relativistic frame dragging and binary companion. We characterize the impact of the disc ‘critical obliquity’, which marks regions of the parameter space where stationary solutions do not exist. We find that black hole spins reach either complete alignment or a critical configuration. Reaching the critical obliquity might imply that the disc breaks as observed in hydrodynamical simulations. Our findings are important to predict the spin configurations with which supermassive black hole binaries enter their gravitational-wave driven regime and become detectable by LISA.

scholarly journals FORMATION AND HARDENING OF SUPERMASSIVE BLACK HOLE BINARIES IN MINOR MERGERS OF DISK GALAXIES

2012 ◽  
Vol 756 (1) ◽  
pp. 30 ◽  
Author(s):  
Fazeel Mahmood Khan ◽  
Ingo Berentzen ◽  
Peter Berczik ◽  
Andreas Just ◽  
Lucio Mayer ◽  
...  
Keyword(s):  
Black Hole ◽  
Disk Galaxies ◽  
Black Hole Binaries ◽  
Supermassive Black Hole ◽  
Minor Mergers

scholarly journals Constraints on ultra-low-frequency gravitational waves with statistics of pulsar spin-down rates

2019 ◽  
Vol 489 (3) ◽  
pp. 3547-3552
Author(s):  
Hiroki Kumamoto ◽  
Yuya Imasato ◽  
Naoyuki Yonemaru ◽  
Sachiko Kuroyanagi ◽  
Keitaro Takahashi
Keyword(s):  
Black Hole ◽  
Gravitational Waves ◽  
Time Derivative ◽  
Low Frequency ◽  
Upper Bounds ◽  
Galactic Centre ◽  
Frequency Range ◽  
Rate Distribution ◽  
Black Hole Binaries ◽  
Supermassive Black Hole

Abstract We probe ultra-low-frequency gravitational waves (GWs) with statistics of spin-down rates of millisecond pulsars (thereafter MSPs) by a method proposed in our previous work. The considered frequency range is 10−12 Hz ≲ fGW ≲ 10−10  Hz . The effect of such low-frequency GWs appears as a bias to spin-down rates that has a quadrupole pattern in the sky. We use the skewness of the spin-down rate distribution and the number of MSPs with negative spin-down rates to search for the bias induced by GWs. Applying this method to 149 MSPs selected from the ATNF pulsar catalogue, we derive upper bounds on the time derivative of the GW amplitudes of $\dot{h} \lt 6.2 \times 10^{-18}~{\rm s}^{-1}$ and $\dot{h} \lt 8.1 \times 10^{-18}~{\rm s}^{-1}$ in the directions of the Galactic Centre and M87, respectively. Approximating the GW amplitude as $\dot{h} \sim 2 \pi f_{\rm GW} h$, the bounds translate into h < 3 × 10−8 and h < 4 × 10−8, respectively, for fGW = 1/(1000 yr). Finally, we give the implications to possible supermassive black hole binaries at these sites.

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