BLINDLY DETECTING MERGING SUPERMASSIVE BLACK HOLES WITH RADIO SURVEYS

Journal Article · Mon Jun 20 04:00:00 EDT 2011 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/734/2/L37· OSTI ID:21562593

Kaplan, D L; O'Shaughnessy, R ^[1]; Sesana, A ^[2]; Volonteri, M ^[3]

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1. Physics Department and Center for Gravitation and Cosmology, University of Wisconsin-Milwaukee, Milwaukee WI 53211 (United States)
2. Albert Einstein Institute, Am Muhlenberg 1 D-14476 Golm (Germany)
3. Astronomy Department, University of Michigan, Ann Arbor, MI 48109 (United States)

Supermassive black holes (SMBHs) presumably grow through numerous mergers throughout cosmic time. During each merger, SMBH binaries are surrounded by a circumbinary accretion disk that imposes a significant ({approx}10{sup 4} G for a binary of 10{sup 8} M{sub sun}) magnetic field. The motion of the binary through that field will convert the field energy to Poynting flux, with a luminosity {approx}10{sup 43} erg s{sup -1} (B/10{sup 4} G){sup 2}(M/10{sup 8} M{sub sun}){sup 2}, some of which may emerge as synchrotron emission at frequencies near 1 GHz where current and planned wide-field radio surveys will operate. We find that the short timescales of many mergers will limit their detectability with most planned blind surveys to <1 per year over the whole sky, independent of the details of the emission process and flux distribution. Including an optimistic estimate for the radio flux makes detection even less likely, with <0.1 mergers per year over the whole sky. However, wide-field radio instruments may be able to localize systems identified in advance of merger by gravitational waves. Further, radio surveys may be able to detect the weaker emission produced by the binary's motion as it is modulated by spin-orbit precession and inspiral well in advance of merger.

• OSTI ID: 21562593
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 2 Vol. 734; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ACCRETION DISKS
BINARY STARS
BLACK HOLES
EMISSION
GRAVITATIONAL WAVES
LUMINOSITY
MAGNETIC FIELDS
MOTION
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
STARS