Observing the Galaxy's massive black hole with gravitational wave bursts
Abstract
An extrememassratio burst (EMRB) is a gravitational wave signal emitted when a compact object passes through periapsis on a highly eccentric orbit about a much more massive body, in our case a stellar mass object about a 10^{6} M_{☉} black hole. EMRBs are a relatively unexplored means of probing the spacetime of massive black holes (MBHs). We conduct an investigation of the properties of EMRBs and how they could allow us to constrain the parameters, such as spin, of the Galaxy's MBH. We find that if an EMRB event occurs in the Galaxy, it should be detectable for periapse distances r_{p} < 65r_{g} for a μ = 10 M_{☉} orbiting object, where r_{g} = GM_{∙}/c^{2} is the gravitational radius. The signaltonoise ratio scales as log (ρ) ≃ 2.7 log (r_{p}/r_{g}) + log (μ/M_{☉}) + 4.9. For periapses r_{p} ≲ 10r_{g}, EMRBs can be informative, and provide good constraints on both the MBH's mass and spin. Closer orbits provide better constraints, with the best giving accuracies of better than one part in 10^{4} for both the mass and spin parameter.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 February 2013
 DOI:
 10.1093/mnras/sts360
 arXiv:
 arXiv:1210.2778
 Bibcode:
 2013MNRAS.429..589B
 Keywords:

 black hole physics;
 gravitational waves;
 methods: data analysis;
 Galaxy: centre;
 Astrophysics  High Energy Astrophysical Phenomena;
 Astrophysics  Cosmology and Extragalactic Astrophysics;
 Astrophysics  Galaxy Astrophysics;
 Astrophysics  Instrumentation and Methods for Astrophysics;
 General Relativity and Quantum Cosmology
 EPrint:
 25 pages, 17 figures, 1 appendix. One more typo fixed