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Abstract Supermassive binary black holes are a key target for the future Laser Interferometer Space Antenna and excellent multimessenger sources across the electromagnetic (EM) spectrum. However, unique features of their EM emission that are needed to distinguish them from single supermassive black holes are still being established. Here, we conduct the first magnetohydrodynamic simulation of disk accretion onto equal-mass, nonspinning, eccentric binary black holes in full general relativity, incorporating synchrotron radiation transport through the dual jet in postprocessing. Focusing on a binary in the strong-field dynamical spacetime regime with eccentricitye= 0.3 as a point of principle, we show that the total accretion rate exhibits periodicity on the binary orbital period. We also show, for the first time, that this periodicity is reflected in the jet Poynting luminosity and the optically thin synchrotron emission from the jet base. Furthermore, we find a distinct EM signature for eccentric binaries: they spend more time in a low emission state (at apocenter) and less in a high state (at pericenter). Additionally, we find that the eccentric binary quasiperiodic gravitational-wave (GW) bursts are coincident with the bursts in Poynting luminosity and synchrotron emission. Finally, we discuss how multimessenger EM and GW observations of these systems can help probe plasma physics in their jet.
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This content will become publicly available on March 13, 2026
Disk Draining in LIGO Progenitor Black Hole Binaries and Its Significance to Electromagnetic Counterparts
Abstract The effect of tidal forces on transport within a relic accretion disk in binary black holes is studied here with a suite of two-dimensional hydrodynamic simulations. As the binary contracts owing to the emission of gravitational waves, the accretion disk is truncated, and a two-armed spiral wave is excited, which remains stationary in the rotating reference frame of the coalescing binary. Such spiral waves lead to increased transport of mass and angular momentum. Our findings suggest that even in the case of weakly ionized accretion disks spiral density waves will drain the disk long before the orbit of the two black holes decays enough for them to merge, thus dimming prospects for a detectable electromagnetic counterpart.
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- Award ID(s):
- 2307710
- PAR ID:
- 10630392
- Publisher / Repository:
- The Astrophysical Journal Letters
- Date Published:
- Journal Name:
- The Astrophysical Journal Letters
- Volume:
- 982
- Issue:
- 1
- ISSN:
- 2041-8205
- Page Range / eLocation ID:
- L11
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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