TIME-DEPENDENT MODELS FOR THE AFTERGLOWS OF MASSIVE BLACK HOLE MERGERS

Journal Article · Sat May 01 04:00:00 EDT 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/714/1/404· OSTI ID:21448933

Tanaka, Takamitsu; Menou, Kristen ^[1]

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1. Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027 (United States)

The Laser Interferometer Space Antenna (LISA) will detect gravitational wave signals from coalescing pairs of massive black holes (MBHs) in the total mass range (10{sup 5}-10{sup 7})/(1 + z) M{sub sun} out to cosmological distances. Identifying and monitoring the electromagnetic (EM) counterparts of these events would enable cosmological studies and offer new probes of gas physics around well-characterized MBHs. Milosavljevic and Phinney proposed that a circumbinary disk around a binary of mass {approx}10{sup 6} M{sub sun} will emit an accretion-powered X-ray afterglow approximately one decade after the gravitational wave event. We revisit this scenario by using Green's function solutions to calculate the temporal viscous evolution and the corresponding EM signature of the circumbinary disk. Our calculations suggest that an EM counterpart may become observable as a rapidly brightening source soon after the merger, i.e., several years earlier than previously thought. The afterglow can reach super-Eddington luminosities without violating the local Eddington flux limit. It is emitted in the soft X-ray by the innermost circumbinary disk, but it may be partially reprocessed at optical and infrared frequencies. We also find that the spreading disk becomes increasingly geometrically thick close to the central object as it evolves, indicating that the innermost flow could become advective and radiatively inefficient, and generate a powerful outflow. We conclude that the mergers of MBHs detected by LISA offer unique opportunities for monitoring, on humanly tractable timescales, the viscous evolution of accretion flows and the emergence of outflows around MBHs with precisely known masses, spins, and orientations.

• OSTI ID: 21448933
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 714; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ACCRETION DISKS
AFTERGLOW
ANTENNAS
BLACK HOLES
COSMIC RADIO SOURCES
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
ELECTRICAL EQUIPMENT
ELECTROMAGNETIC RADIATION
EQUIPMENT
EVOLUTION
FUNCTIONS
GALACTIC EVOLUTION
GALAXIES
GRAVITATIONAL WAVES
GREEN FUNCTION
INTERFEROMETERS
IONIZING RADIATIONS
LUMINOSITY
MASS
MEASURING INSTRUMENTS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
QUASARS
RADIATIONS
SOFT X RADIATION
TIME DEPENDENCE
X RADIATION
X-RAY GALAXIES