Using Pulsars to Detect Massive Black Hole Binaries via Gravitational Radiation: Sagittarius A~* and Nearby Galaxies

摘要

Pulsar timing measurements can be used to detect gravitational radiation from massive black hole binaries. The ～106 day quasi-periodic flux variations in Sagittarius A~* (Sgr A~*) at radio wavelengths reported by Zhao, Bower, & Goss may be due to binarity of the massive black hole that is presumed to be responsible for the radio emission. A 106 day equal-mass binary black hole is unlikely based on its short inspiral lifetime and other arguments. Nevertheless the reported quasi-periodicity has led us to consider whether the long-wavelength gravitational waves from a conjectured binary might be detected in present or future precision timing of millisecond pulsars.