Formation and Evolution of Compact Object Binaries in AGN Disks
Reviewed by Pith T0 review T1 audit T2 compute T3 formal T4 reserved pith:XS4YDNT2record.jsonopen to challenge →
read the original abstract
The astrophysical origin of gravitational wave (GW) events discovered by LIGO/VIRGO remains an outstanding puzzle. In active galactic nuclei (AGN), compact-object binaries form, evolve, and interact with a dense star cluster and a gas disk. An important question is whether and how binaries merge in these environments. To address this question, we have performed one-dimensional $N$-body simulations combined with a semi-analytical model which includes the formation, disruption, and evolution of binaries self-consistently. We point out that binaries can form in single-single interactions by the dissipation of kinetic energy in a gaseous medium. This ``gas capture'' binary formation channel contributes up to $97\,\%$ of gas-driven mergers and leads to a high merger rate in AGN disks even without pre-existing binaries. We find the merger rate to be in the range $\sim 0.02-60\,\mathrm{Gpc^{-3}yr^{-1}}$. The results are insensitive to the assumptions on gaseous hardening processes: we find that once they are formed, binaries merge efficiently via binary-single interactions even if these gaseous processes are neglected. We find that the average number of mergers per BH is $0.4$, and the probability for repeated mergers in 30 Myr is $\sim 0.21-0.45$. High BH masses due to repeated mergers, high eccentricities, and a significant Doppler drift of GWs are promising signatures which distinguish this merger channel from others. Furthermore, we find that gas-capture binaries reproduce the distribution of LMXBs in the Galactic center, including an outer cutoff at $\sim1$ pc due to the competition between migration and hardening by gas torques.
This paper has not been read by Pith yet.
Forward citations
Cited by 12 Pith papers
-
Orbital evolution of asymmetric binaries within accreting environments
Disk-induced dissipation drives rapid orbital plane alignment followed by slower eccentricity damping in extreme mass-ratio inspirals, with relativistic effects producing accumulating deviations from Keplerian orbits ...
-
Self-acceleration of Hardening Binaries
Hardening binaries experience deterministic self-acceleration of their center of mass, induced precession, and plane rotation in uniform isotropic media, driving outward spiraling and eccentricity growth in all cases ...
-
The third wheel: ringdown and lensing of triple systems
Numerical relativity simulations of triple black hole systems reveal redshift effects and gravitational lensing in ringdown signals from head-on mergers, with no additional black hole formation from amplified waves.
-
Implications of the LISA stochastic signal from eccentric stellar mass black hole binaries in vacuum
High initial eccentricities in stellar-mass black hole binaries produce a stochastic gravitational wave background distinguishable by LISA from quasi-circular models, enabling upper bounds on eccentricity and separati...
-
Post-Newtonian inspiral waveform model for eccentric precessing binaries with higher-order modes and matter effects
pyEFPEHM extends prior PN models to include higher-order quasi-circular phasing, generalized precession solutions, and eccentric corrections up to 1PN in selected multipoles for eccentric precessing binaries with matt...
-
Thick Disks, Thin Hopes: Suppressed Capture and Merger Rates in AGN
AGN disk capture and merger rates scale as (H/R)^{-8} and drop by 10-20 orders of magnitude in thick magnetically supported disks compared to thin thermal disks.
-
Scalar fields around black hole binaries in LIGO-Virgo-KAGRA
Semi-analytic waveform model for scalar environments around black hole binaries is validated against numerical relativity and applied to LIGO-Virgo-KAGRA data to obtain upper limits on scalar densities with tentative ...
-
GW231123: A Possible Primordial Black Hole Origin
GW231123's masses and high spins are consistent with primordial black holes that accreted mass and angular momentum in the early universe within the standard PBH framework.
-
A Possible Triple Formation Scenario of Binary Black Hole Merge With One In Pair-instability Supernova Mass Gap
An isolated hierarchical triple channel with chemically homogeneous evolution and triple common envelope can produce PISN mass-gap BBH mergers matching GW190706 at ~22% of the observed rate.
-
Dynamics of Relativistic Binaries in Structured and Stochastic Environments: A Lagrange-Fourier-Hansen Framework
A new framework projects perturbations onto resonant frequencies via Hansen coefficients to produce efficient coupled ODEs for orbital elements in GW-driven relativistic binaries, demonstrated on tidal fields and accr...
-
Evidence for additional structure in the effective spin distribution hints at multiple formation pathways in GWTC-5.0
GWTC-5.0 analysis finds evidence for structure beyond a non-skewed Gaussian bulk in χ_eff, with suggestive mass-dependent excess of positive over negative spins outside the bulk at 13:1 odds in one mass bin.
-
Waveform Modelling for the Laser Interferometer Space Antenna
A review of existing waveform models for LISA sources and the challenges that must still be overcome.
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.