Gravitational wave energy spectrum of a parabolic encounter
Abstract
We derive an analytic expression for the energy spectrum of gravitational waves from a parabolic Keplerian binary by taking the limit of the Peters and Mathews spectrum for eccentric orbits. This demonstrates that the location of the peak of the energy spectrum depends primarily on the orbital periapse rather than the eccentricity. We compare this weakfield result to strongfield calculations and find it is reasonably accurate (∼10%) provided that the azimuthal and radial orbital frequencies do not differ by more than ∼10%. For equatorial orbits in the Kerr spacetime, this corresponds to periapse radii of r_{p}≳20M. These results can be used to model radiation bursts from compact objects on highly eccentric orbits about massive black holes in the local Universe, which could be detected by the Laser Interferometer Space Antenna (LISA).
 Publication:

Physical Review D
 Pub Date:
 November 2010
 DOI:
 10.1103/PhysRevD.82.107501
 arXiv:
 arXiv:1010.3865
 Bibcode:
 2010PhRvD..82j7501B
 Keywords:

 04.30.w;
 04.25.Nx;
 97.60.Lf;
 98.35.Jk;
 Gravitational waves: theory;
 PostNewtonian approximation;
 perturbation theory;
 related approximations;
 Black holes;
 Galactic center bar circumnuclear matter and bulge;
 General Relativity and Quantum Cosmology;
 Astrophysics  Cosmology and Extragalactic Astrophysics;
 Astrophysics  Galaxy Astrophysics;
 Astrophysics  High Energy Astrophysical Phenomena
 EPrint:
 5 pages, 3 figures. Minor changes to match published version