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arXiv · 2509.18254

Binary black holes gone MAD: Magnetically arrested minidisks around nonspinning black holes

Vikram Manikantan·Vasileios Paschalidis
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Abstract

We demonstrate the formation of magnetically arrested minidisks (MAM) around equal-mass, nonspinning binary black holes with magnetohydrodynamic simulations of circumbinary disk accretion in full 3+1 general relativity. The initial separation of $d\sim 30\,M$ allows the black holes to host large minidisks that suppress the total rest-mass accretion rate variability, which is modulated primarily at $\sim 1.6 \, f_{\rm orb}$. Each black hole horizon saturates with dimensionless magnetic flux $\phi \sim 30$. Magnetic reconnection near the horizons drives recurrent eruptions which are expected to drive flaring in the infrared and X-ray bands. Our results establish MAMs as a new outcome of circumbinary disk accretion, and a promising source of novel electromagnetic counterparts to gravitational waves from binary black holes.

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Vikram Manikantan, Vasileios Paschalidis. 2025-09-22. Binary black holes gone MAD: Magnetically arrested minidisks around nonspinning black holes. https://doi.org/10.1103/g98b-m8m1

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