Radiation Magnetohydrodynamic Simulation of sub-Eddington Circumbinary Disk around an Equal-mass Massive Black Hole Binary

Fuente: arXiv
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Main Authors: Tiwari, Vishal, Chan, Chi-Ho, Bogdanović, Tamara, Jiang, Yan-Fei, Davis, Shane W., Ferrel, Simon
Format: Preprint
Published: 2025
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author Tiwari, Vishal
Chan, Chi-Ho
Bogdanović, Tamara
Jiang, Yan-Fei
Davis, Shane W.
Ferrel, Simon
author_facet Tiwari, Vishal
Chan, Chi-Ho
Bogdanović, Tamara
Jiang, Yan-Fei
Davis, Shane W.
Ferrel, Simon
contents We present the first three-dimensional radiation magnetohydrodynamic (RMHD) simulation of a sub-Eddington circumbinary disk (CBD) around an equal-mass massive black hole binary (MBHB) with a total mass of $2\,\times\,10^7\,M_{\odot}$ on a circular orbit, separated by 100$\,GM_{\rm tot}/c^2$. The inclusion of radiation leads to a denser, thinner, and more filamentary disk compared to non-radiative magnetohydrodynamic simulation, primarily due to reduced pressure support and an altered equation of state. The RMHD disk also features $\sim 3$ times lower accretion rate ($\approx 0.15\,\dot{M}_{\rm Edd}$), weaker accretion streams and a less pronounced overdensity (a.k.a., ``lump") at the inner edge. Our analysis of the light curves and thermal spectra reveals that the variability induced by the binary-CBD interaction is distinguishable in the optical/UV band, where CBD shines at about $1\%$ of the Eddington luminosity. These findings underscore the crucial role of radiation on the structure and observational properties of CBDs around massive black hole binaries and have implications for detecting electromagnetic counterparts to LISA gravitational wave precursors, and for heavier binaries that are Pulsar Timing Array sources.
format Preprint
id arxiv_https___arxiv_org_abs_2502_18584
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Radiation Magnetohydrodynamic Simulation of sub-Eddington Circumbinary Disk around an Equal-mass Massive Black Hole Binary
Tiwari, Vishal
Chan, Chi-Ho
Bogdanović, Tamara
Jiang, Yan-Fei
Davis, Shane W.
Ferrel, Simon
High Energy Astrophysical Phenomena
Astrophysics of Galaxies
We present the first three-dimensional radiation magnetohydrodynamic (RMHD) simulation of a sub-Eddington circumbinary disk (CBD) around an equal-mass massive black hole binary (MBHB) with a total mass of $2\,\times\,10^7\,M_{\odot}$ on a circular orbit, separated by 100$\,GM_{\rm tot}/c^2$. The inclusion of radiation leads to a denser, thinner, and more filamentary disk compared to non-radiative magnetohydrodynamic simulation, primarily due to reduced pressure support and an altered equation of state. The RMHD disk also features $\sim 3$ times lower accretion rate ($\approx 0.15\,\dot{M}_{\rm Edd}$), weaker accretion streams and a less pronounced overdensity (a.k.a., ``lump") at the inner edge. Our analysis of the light curves and thermal spectra reveals that the variability induced by the binary-CBD interaction is distinguishable in the optical/UV band, where CBD shines at about $1\%$ of the Eddington luminosity. These findings underscore the crucial role of radiation on the structure and observational properties of CBDs around massive black hole binaries and have implications for detecting electromagnetic counterparts to LISA gravitational wave precursors, and for heavier binaries that are Pulsar Timing Array sources.
title Radiation Magnetohydrodynamic Simulation of sub-Eddington Circumbinary Disk around an Equal-mass Massive Black Hole Binary
topic High Energy Astrophysical Phenomena
Astrophysics of Galaxies
url https://arxiv.org/abs/2502.18584