[1109.0572] The Chimera Scheme: Approximate Waveforms for Extreme-Mass-Ratio Inspirals

Authors: Carlos F. Sopuerta, Nicolás Yunes

Date: 2 Sep 2011

Abstract: We introduce the Chimera scheme, a new framework to model the dynamics of generic extreme mass-ratio inspirals (stellar compact objects spiraling into a spinning super-massive black hole) and to produce the gravitational waveforms that describe the gravitational wave emission of these systems. The Chimera scheme combines techniques from black hole perturbation theory and post-Minkowskian theory. The orbital evolution is approximated as a sequence of osculating geodesics that shrink due to the stellar compact object's self-acceleration. Lacking a general prescription for this self-force, we here approximate it locally in time via a post-Minkowskian expansion. The orbital evolution is thus equivalent to evolving the geodesic equations with time-dependent orbital elements, as dictated by this post-Minkowskian radiation-reaction prescription. Gravitational radiation is modeled via a multipolar expansion in post-Minkowskian theory, here taken up to mass hexadecapole and current octopole order. To complete the scheme, both the orbital evolution and wave generation require to map the Boyer-Lindquist coordinates of the orbits to the harmonic coordinates in which the different post-Minkowskian quantities have been derived, a mapping that we provide explicitly in this paper. The Chimera scheme is thus a combination of approximations that can be used to model generic inspirals of systems with extreme mass ratios to systems with more moderate mass ratios, and hence can provide valuable information for future space-based gravitational-wave observatories like the Laser Interferometer Space Antenna and even for advanced ground detectors. Finally, due to the local character in time of our post-Minkowskian self-force, the Chimera scheme can be used to perform studies of the possible appearance of transient resonances in generic inspirals.

abs pdf

Sep 09, 2011

1109.0572 (/preprints)
2011-09-09, 06:51 [edit]

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