Speaker
Lorenz Zwick
(ICS UZH)
Description
We compute a revised version of Peters' (1964) time-scale for the gravitational-wave (GW) induced decay of two point masses, by taking into account post-Newtonian (PN) perturbations of the orbital motion. In the standard approach of neglecting the time evolution of the eccentricity, the corrected time-scale can be approximated by multiplying Peters' estimate by the simple factor $Q = 1 + 5 (r_{\rm S}/p)$, where $p$ is the periapsis and $r_{\rm S}$ the Schwarzschild radius of the system. The difference between the Newtonian and the corrected result increases if large eccentricities (-0.5) are evolved self-consistently, and we provide both a fit and a simple recipe to compute the correct time-scale.
We apply the revised time-scalereds to a set of typical sources for existing ground-based laser interferometers and for the future Laser Interferometer Space Antenna (LISA), at the onset of their GW driven decay. We argue that our more accurate model for the orbital evolution will affect current event- and detection-rate estimates for mergers of compact object binaries, with stronger deviations for LISA sources, such as extreme and intermediate mass-ratio inspirals and supermassive black hole binaries. We propose the correction factor $Q$ as a simple analytical prescription to quantify decay time-scales more accurately in future population synthesis models.
Primary author
Lorenz Zwick
(ICS UZH)
Co-authors
Dr
Elisa Bortolas
(University of Zurich)
Prof.
Lucio Mayer
(University of Zurich)
Dr
Pedro Capelo
(University of Zurich)
