2002/11/07 by R. O'Shaughnessy · 1 citation
Physics and Astronomy · #gr-qc
paper · pdf · doi:10.1103/physrevd.67.044004
published as Phys.Rev.D67:044004,2003 · Submitted to PRD
arxiv created 2002/11/07 · arxiv updated 2009/11/30
Ori and Thorne have discussed the duration and observability (with LISA) of the transition from circular, equatorial inspiral to plunge for stellar-mass objects into supermassive (105-108M\odot) Kerr black holes. We extend their computation to eccentric Kerr equatorial orbits. Even with orbital parameters near-exactly determined, we find that there is no universal length for the transition; rather, the length of the transition depends sensitively -- essentially randomly -- on initial conditions. Still, Ori and Thorne's zero-eccentricity results are essentially an upper bound on the length of eccentric transitions involving similar bodies (e.g., a fixed). Hence the implications for observations are no better: if the massive body is M=106M\odot, the captured body has mass m, and the process occurs at distance d from LISA, then S/N \lesssim (m/10 M\odot)(1Gpc/d)× O(1), with the precise constant depending on the black hole spin. For low-mass bodies (m \lesssim 7 M_\odot) for which the event rate is at least vaguely understood, we expect little chance (probably [much] less than 10%, depending strongly on the astrophysical assumptions) of LISA detecting a transition event with S/N>5 during its run; however, even a small infusion of higher-mass bodies or a slight improvement in LISA's noise curve could potentially produce S/N>5 transition events during LISA's lifetime.