Related papers: Hierarchical Black Hole Mergers in Active Galactic…
There is much debate about the channels for astrophysical origins of the stellar-mass binary black hole (BBH) mergers detected by LIGO and Virgo. Active galactic nuclei (AGNs) are promising sites for the efficient formation and rapid…
The dense and gaseous environments of active galactic nuclei (AGNs) can catalyze repeated mergers of stellar-mass black holes (BHs), potentially explaining the high-mass tail of binary black hole (BBH) mergers observed by LIGO-Virgo-KAGRA…
Black hole mergers detectable with LIGO can occur in active galactic nucleus (AGN) disks. Here we parameterize the merger rates, the mass spectrum and the spin spectrum of black holes (BH) in AGN disks. The predicted merger rate spans $\sim…
The origin of the black hole mergers detected by LIGO and Virgo remains an open question. While the unusual mass and spin of a few events constrain their possible astrophysical formation mechanisms, it is difficult to classify the bulk of…
We review theoretical findings, astrophysical modeling, and current gravitational-wave evidence of hierarchical stellar-mass black-hole mergers. While most of the compact binary mergers detected by LIGO and Virgo are expected to consist of…
The astrophysical origin of gravitational wave (GW) transients is a timely open question in the wake of discoveries by LIGO/Virgo. In active galactic nuclei (AGNs), binaries form and evolve efficiently by interaction with a dense population…
Star clusters (SCs) and active galactic nuclei (AGNs) are promising sites for the occurrence of hierarchical black hole (BH) mergers. We use simple models to compare hierarchical BH mergers in two of the dynamical formation channels. We…
Most of the binary black hole (BBH) mergers detected by LIGO and Virgo could be explained by first-generation mergers formed from the collapse of stars, while others might come from second (or higher) generation mergers, namely hierarchical…
One of the proposed channels of binary black hole mergers involves dynamical interactions of three black holes. In such scenarios, it is possible that all three black holes merge in a so-called hierarchical merger chain, where two of the…
The detection of gravitational waves from merging black holes with masses $\sim\,80-150\,\mathrm{M_\odot}$ suggests that some proportion of black hole binary systems form hierarchically in dense astrophysical environments, as most stellar…
Merging black holes (BH) are expected to produce remnants with large dimensionless spin parameters ($a_{\rm spin} \sim 0.7$). However, gravitational wave (GW) observations with LIGO/Virgo suggest that merging BH are consistent with modestly…
Advanced LIGO \& Advanced Virgo are detecting a large number of binary stellar origin black hole (BH) mergers. A promising channel for accelerated BH merger lies in active galactic nucleus (AGN) disks of gas around super-masssive black…
We infer the origin channels of hierarchical mergers observed in the LIGO-Virgo-KAGRA (LVK) O1, O2, and O3 runs using a hierarchical Bayesian analysis under a parametric population model. By assuming the active galactic nucleus (AGN) disk…
Active galactic nucleus (AGN) disks may be important sites of binary black hole (BBH) mergers. Here we show via numerical experiments with the high-accuracy, high precision code {\tt SpaceHub} that broken symmetry in dynamical encounters in…
We investigate secular evolution in hierarchical quadruple systems as a formation channel of mass-gap black holes (with masses of about $3-5$ $M_{\odot}$) in systems that will eventually lead to binary black hole mergers detectable by…
Observations by LIGO--Virgo of binary black hole mergers suggest a possible anti-correlation between black hole mass ratio ($q=m_{2}/m_{1}$) and the effective inspiral spin parameter $\chi_{\rm eff}$, the mass-weighted spin projection onto…
GW190521 was the most massive black hole merger discovered by LIGO/Virgo so far, with masses in tension with stellar evolution models. A possible explanation of such heavy black holes is that they themselves are the remnants of previous…
LIGO/Virgo has detected several binary black hole (BBH) merger events that may have originated in the accretion disks of Active Galactic Nuclei (AGN). These events require individual black hole masses that fall within the pair instability…
The growing number of stellar-mass binary black hole mergers discovered by Advanced LIGO and Advanced Virgo are starting to constrain the binaries' origin and environment. However, we still lack sufficiently accurate modeling of binary…
The high rate of black hole (BH) mergers detected by LIGO/Virgo opened questions on their astrophysical origin. One possibility is the dynamical channel, in which binary formation and hardening is catalyzed by dynamical encounters in…