Related papers: Where Are Be/black-hole Binaries?
The majority of the ultraluminous X-ray sources (ULXs) in external galaxies are believed to be accreting black holes in binary systems; some of the black holes could be as massive as $\sim 100-1000 \ms$. We have performed evolution…
Accretion onto black holes is one of the most efficient energy source in the Universe. Black hole accretion powers some of the most luminous objects in the universe, including quasars, active galactic nuclei, tidal disruption events,…
Observations of exoplanets and protoplanetary disks show that binary stellar systems can host planets in stable orbits. Given the high binary fraction among stars, the contribution of binary systems to Galactic habitability should be…
The majority of known Galactic black holes reside in low-mass X-ray binaries. They are rare and fascinating objects, providing unique information on strong gravity, accretion disc physics, and stellar and binary evolution. There is no doubt…
We present the result of $N$-body simulations of dynamical evolution of triple massive blackhole (BH) systems in galactic nuclei. We found that in most cases two of the three BHs merge through gravitational wave (GW) radiation in the…
We present numerical simulations of binary black hole systems which for the first time last for about one orbital period for close but still separate black holes as indicated by the absence of a common apparent horizon. An important part of…
Beyond all reasonable doubt, black holes are commonly found in the nuclei of most normal galaxies. In recent years, dynamical measurements of hole masses have transformed the study of their functioning and evolution. In particular, relating…
The two systems, namely, Gaia~BH1 and Gaia~BH2, that have been confirmed as dormant (i.e., no X-ray emission detected) black hole (BH) - low-mass star binaries in the latest Gaia mission data release (DR3) are intriguing in the context of…
Galaxies are believed to evolve through merging, which should lead to multiple supermassive black holes in some. There are four known triple black hole systems, with the closest pair being 2.4 kiloparsecs apart (the third component is more…
The stellar ejection rate and the rates of change of the binary semimajor axis and eccentricity are derived from scattering experiments for the restricted three-body problem. They are used to study the evolution of binaries in simple models…
Recently, compact black hole X-ray binaries XTE J 1118+480 and A0620-00 have been reported to be experiencing a fast orbital period decay, which is two orders of magnitude higher than expected with gravitational wave radiation. Magnetic…
[Abridged] In galactic nuclei with sufficiently short relaxation times, binary supermassive black holes can evolve beyond their stalling radii via continued interaction with stars. We study this "collisional" evolutionary regime using both…
We discuss a new N-body simulation method for studying black hole binary dynamics. This method avoids previous numerical problems due to large mass ratios and trapped orbits with short periods. A treatment of relativistic effects is…
The evolution of the spin and tilt of black holes in compact black hole - neutron star and black hole - black hole binary systems is investigated within the framework of the coalescing compact star binary model for short gamma ray bursts…
We consider compact binary systems, modeled in general relativity as vacuum or perfect-fluid spacetimes with a helical Killing vector k^\alpha, heuristically, the generator of time-translations in a corotating frame. Systems that are…
In this note we suggest that high-mass black holes; i.e., black holes of several solar masses, can be formed in binaries with low-mass main-sequence companions, provided that the hydrogen envelope of the massive star is removed in common…
We use a 3-D relativistic SPH (Smoothed Particle Hydrodynamics) code to study mergers of black hole -- neutron star (BH--NS) binary systems with low mass ratios, adopting $M_{NS}/M_{BH} \simeq 0.1$ as a representative case. The outcome of…
Binary black holes occupy a special place in our quest for understanding the evolution of galaxies along cosmic history. If massive black holes grow at the center of (pre-)galactic structures that experience a sequence of merger episodes,…
We investigate the orbital eccentricity evolution of supermassive black hole binaries within galactic environments. We analyze the dynamics in triaxial merger remnants and subsequent interactions with geometrically thick nuclear discs. We…
(Abridged) To gain insight into the dynamical influence of a supermassive black hole binary on a circumbinary accretion disk, we investigate the binary and viscous torque densities throughout such a disk, with emphasis on the final density…