Circumbinary magnetohydrodynamic accretion into inspiraling binary black holes

Scott C. Noble, Bruno C. Mundim, Hiroyuki Nakano, Julian H. Krolik, Manuela Campanelli, Yosef Zlochower, Nicolás Yunes

Research output: Contribution to journalArticlepeer-review


We have simulated the magnetohydrodynamic evolution of a circumbinary disk surrounding an equal-mass binary comprising two non-spinning black holes during the period in which the disk inflow time is comparable to the binary evolution time due to gravitational radiation. Both the changing spacetime and the binary orbital evolution are described by an innovative technique utilizing high-order post-Newtonian approximations. Prior to the beginning of the inspiral, the structure of the circumbinary disk is predicted well by extrapolation from Newtonian results: a gap of roughly two binary separation radii is cleared, and matter piles up at the outer edge of this gap as inflow is retarded by torques exerted by the binary; the accretion rate is roughly half its value at large radius. During inspiral, the inner edge of the disk initially moves inward in coordination with the shrinking binary, but - as the orbital evolution accelerates - the inward motion of the disk edge falls behind the rate of binary compression. In this stage, the binary torque falls substantially, but the accretion rate decreases by only 10%-20%. When the binary separation is tens of gravitational radii, the rest-mass efficiency of disk radiation is a few percent, suggesting that supermassive binary black holes could be very luminous at this stage of their evolution. Inner disk heating is modulated at a beat frequency comparable to the binary orbital frequency. However, a disk with sufficient surface density to be luminous may be optically thick, suppressing periodic modulation of the luminosity.

Original languageEnglish (US)
Article number51
JournalAstrophysical Journal
Issue number1
StatePublished - Aug 10 2012
Externally publishedYes


  • accretion, accretion disks
  • black hole physics
  • galaxies: nuclei
  • magnetohydrodynamics (MHD)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'Circumbinary magnetohydrodynamic accretion into inspiraling binary black holes'. Together they form a unique fingerprint.

Cite this