Abstract
We present the first magnetohydrodynamic simulation in which a circumbinary disk around a relativistic binary black hole feeds mass to individual accretion disks ("mini-disks") around each black hole. Mass flow through the accretion streams linking the circumbinary disk to the mini-disks is modulated quasi-periodically by the streams' interaction with a nonlinear m = 1 density feature, or "lump," at the inner edge of the circumbinary disk: the stream supplying each mini-disk comes into phase with the lump at a frequency 0.74 times the binary orbital frequency. Because the binary is relativistic, the tidal truncation radii of the mini-disks are not much larger than their innermost stable circular orbits; consequently, the mini-disks' inflow times are shorter than the conventional estimate and are comparable to the stream modulation period. As a result, the mini-disks are always in inflow disequilibrium, with their masses and spiral density wave structures responding to the stream's quasi-periodic modulation. The fluctuations in each mini-disk's mass are so large that as much as 75% of the total mini-disk mass can be contained within a single mini-disk. Such quasi-periodic modulation of the mini-disk structure may introduce distinctive time-dependent features in the binary's electromagnetic emission.
Original language | English |
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Article number | L17 |
Journal | Astrophysical Journal Letters |
Volume | 853 |
Issue number | 1 |
DOIs | |
State | Published - Jan 20 2018 |
Externally published | Yes |
Funding
Computational resources were provided by the Blue Waters sustained-petascale computing NSF projects OAC-0832606, OAC-1238993, OAC-1516247 and OAC-1515969, OAC- 0725070. Blue Waters is a joint effort of the University of Illinois at Urbana-Champaign and its National Center for Supercomputing Applications. Additional resources were provided by XSEDE allocation TG-PHY060027N and by the BlueSky Cluster at Rochester Institute of Technology. The BlueSky cluster was supported by NSF grants AST-1028087, PHY-0722703, and PHY-1229173. We thank Mark J. Avara for a careful reading of this manuscript and for helpful discussions and suggestions. D.B. would also like to thank Brennan Ireland for helpful discussions. We would like to thank the anonymous referee for the careful reading of this manuscript and for the helpful comments and questions raised. D.B., M.C., V.M., and M.Z. received support from NSF grants AST-1028087, AST-1516150, PHY-1305730, PHY-1707946, OAC-1550436, and OAC-1516125. S.C.N. was supported by AST-1028087, AST-1515982, and OAC-1515969, and by an appointment to the NASA Postdoctoral Program at the Goddard Space Flight Center administrated by USRA through a contract with NASA. J.H.K. was partially supported by NSF grants AST-1516299, PHYS-1707826, and OAC-1516247. V.M. also acknowledges partial support from AYA2015-66899-C2-1-P. M.Z. acknowledges support through the FCT (Portugal) IF programme, IF/00729/2015. Computational resources were provided by the Blue Waters sustained-petascale computing NSF projects OAC-0832606, OAC-1238993, OAC-1516247 and OAC-1515969, OAC-0725070. Blue Waters is a joint effort of the University of Illinois at Urbana-Champaign and its National Center for Supercomputing Applications. Additional resources were provided by XSEDE allocation TG-PHY060027N and by the BlueSky Cluster at Rochester Institute of Technology. The BlueSky cluster was supported by NSF grants AST-1028087, PHY-0722703, and PHY-1229173.
Keywords
- accretion, accretion disks
- black hole physics
- magnetohydrodynamics (MHD)