Radiation Magnetohydrodynamic Simulation of Sub-Eddington Circumbinary Disk in a 10:1 Massive Black Hole Binary
- 1Georgia Institute of Technology
- 2Flatiron Institute
- 3University of Virginia
Abstract
We present a global 3D radiation magnetohydrodynamic (RMHD) simulation of a circumbinary disk (CBD) around a massive black hole binary (MBHB) with a total mass 2 × 10 ⁷ M ⊙ and mass ratio 0.1, separated by 100 GM tot / c ² . The inclusion of radiation makes the disk thinner, denser, less eccentric at the inner edge, and more filamentary when compared to an otherwise identical locally isothermal MHD disk. The RMHD disk has an accretion rate ∼ 0.23 M ̇ Edd and produces thermal emission peaking in the near-UV/optical with a luminosity of ∼1% L Edd . Compared with an equal-mass binary with the same total mass, the thermal emission of the CBD around the unequal-mass binary is several orders of magnitude brighter and much more variable at far-UV/soft X-ray frequencies. Similarly, we find that the light curve associated with the 0.1 mass ratio binary exhibits dominant periodicity corresponding to 2 binary orbits, compared to the equal-mass binary that shows periodicity at 2.5–5 binary orbits. Our results highlight the importance of radiation for the structure and observational properties of MBHB CBDs and have implications for detecting electromagnetic counterparts to Laser Interferometer Space Antenna (LISA) gravitational-wave precursors and for the heavier binaries targeted by the pulsar timing arrays.
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BibTeX
@article{tiwari2026radiation,
title = {{Radiation Magnetohydrodynamic Simulation of Sub-Eddington Circumbinary Disk in a 10:1 Massive Black Hole Binary}},
author = {Vishal Tiwari and Chi-Ho Chan and Tamara Bogdanović and Yan-Fei 燕飞 Jiang 姜 and Shane W. Davis},
journal = {The Astrophysical Journal},
year = {2026},
month = oct,
doi = {10.3847/1538-4357/aeb2f5},
url = {https://iopscience.iop.org/article/10.3847/1538-4357/aeb2f5},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Radiation Magnetohydrodynamic Simulation of Sub-Eddington Circumbinary Disk in a 10:1 Massive Black Hole Binary
AU - Vishal Tiwari
AU - Chi-Ho Chan
AU - Tamara Bogdanović
AU - Yan-Fei 燕飞 Jiang 姜
AU - Shane W. Davis
PY - 2026
DA - 2026/10/30
JO - The Astrophysical Journal
DO - 10.3847/1538-4357/aeb2f5
UR - https://iopscience.iop.org/article/10.3847/1538-4357/aeb2f5
AB - We present a global 3D radiation magnetohydrodynamic (RMHD) simulation of a circumbinary disk (CBD) around a massive black hole binary (MBHB) with a total mass 2 × 10 ⁷ M ⊙ and mass ratio 0.1, separated by 100 GM tot / c ² . The inclusion of radiation makes the disk thinner, denser, less eccentric at the inner edge, and more filamentary when compared to an otherwise identical locally isothermal MHD disk. The RMHD disk has an accretion rate ∼ 0.23 M ̇ Edd and produces thermal emission peaking in the near-UV/optical with a luminosity of ∼1% L Edd . Compared with an equal-mass binary with the same total mass, the thermal emission of the CBD around the unequal-mass binary is several orders of magnitude brighter and much more variable at far-UV/soft X-ray frequencies. Similarly, we find that the light curve associated with the 0.1 mass ratio binary exhibits dominant periodicity corresponding to 2 binary orbits, compared to the equal-mass binary that shows periodicity at 2.5–5 binary orbits. Our results highlight the importance of radiation for the structure and observational properties of MBHB CBDs and have implications for detecting electromagnetic counterparts to Laser Interferometer Space Antenna (LISA) gravitational-wave precursors and for the heavier binaries targeted by the pulsar timing arrays.
SN - 1538-4357
SN - 0004-637X
ER -