Scattering and absorption of gravitational plane waves by rotating black holes
| dc.creator | Dolan, Sam R. | |
| dc.date | 2008-01-24 | |
| dc.date | 2008-11-14 | |
| dc.date.accessioned | 2026-07-07T11:55:31Z | |
| dc.date.available | 2026-07-07T11:55:31Z | |
| dc.description | This is a study of the scattering and absorption of planar gravitational waves by a Kerr black hole in vacuum. We apply the partial wave method to compute cross sections for the special case of radiation incident along the rotation axis. A catalogue of numerically-accurate cross sections is presented, for a range of incident wavelengths $Mω\le 4$ and rotation rates $a \le 0.999M$. Three effects are studied in detail: polarization, helicity-reversal and glory scattering. First, a new approximation to the polarization in the long-wavelength limit is derived. We show that black hole rotation distinguishes between co- and counter-rotating wave helicities, leading to a term in the cross section proportional to $aω$. Second, we confirm that helicity is not conserved by the scattering process, and show that superradiance amplifies the effect. For certain wavelengths, the back-scattered flux is enhanced by as much as $\sim 35$ times for a rapidly-rotating hole (e.g. for $a = 0.999M$ at $Mω= 0.945$). Third, we observe regular glory and spiral scattering peaks in the numerically-determined cross sections. We show that the angular width and intensity of the peaks may be estimated via a semi-classical approximation. We conclude with a discussion of the observable implications of our results. | |
| dc.description | 43 pages, 17 figures. To match published version | |
| dc.identifier | https://arxiv.org/abs/0801.3805 | |
| dc.identifier | http://arxiv.org/abs/0801.3805 | |
| dc.identifier | Class.Quant.Grav.25:235002,2008 | |
| dc.identifier | doi:10.1088/0264-9381/25/23/235002 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/205272 | |
| dc.subject | General Relativity and Quantum Cosmology | |
| dc.subject | Astrophysics | |
| dc.title | Scattering and absorption of gravitational plane waves by rotating black holes | |
| dc.type | text |