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Gravitational waves from hyper-accretion on to nascent black holes

Araya-Góchez, Rafael A. (2004) Gravitational waves from hyper-accretion on to nascent black holes. Monthly Notices of the Royal Astronomical Society, 355 (2). pp. 336-344. ISSN 0035-8711. doi:10.1111/j.1365-2966.2004.07851.x.

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We examine the possibility that hyper-accretion on to newly born black holes occurs in highly intermittent, non-asymmetric fashion favourable to gravitational-wave emission in a neutrino-cooled disc. This picture of near-hole accretion is motivated by magnetorotationally induced, ultrarelativistic disc dynamics in the region of the flow bounded from below by the marginally bound geodesic radius rmb. For high spin values, a largely coherent magnetic field in this region has the dynamical implication of compact mass segregation at the displacement nodes of the non-axisymmetric, magnetorotational instability modes. When neutrino stress competes favourably for the disc dynamical structure, the matter clumps may be rather dense and sufficiently long-lived to excite the quasi-normal ringing (QNR) modes of the Kerr geometry upon infall. We find that this accretion flow may drive bar-like, quadrupole (l, m = 2, 2) modes in nearly resonant fashion for spin parameters a ≥ 0.9. The ensuing build-up in strain amplitude of the undamped oscillations warrants a brisk rate of energy deposition into gravitational waves. A detectability assessment for the LIGO interferometers through the match filtering technique is given by integrating the energy flux over a one-second epoch of resonant hyper-accretion at 1 M_⊙ s^(−1). Thus, a 15-M_⊙ Kerr black hole spinning at a ≃ 0.98 (f_(QNR) ≃ 1677 Hz), and located at 27 Mpc (e.g. GRB 980425), will deliver a characteristic strain amplitude, h_(char) ≃ 2.2−21, large enough to be detectable by LIGO II. If resonant hyper-accretion were sustainable for a longer period (or at higher rates) possibly associated with a second broad hump in a gamma-ray burst light curve, these objects could be detected by LIGO I at very low redshifts.

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Additional Information:© 2004 RAS. Accepted 2004 March 17. Received 2004 February 18; in original form 2003 December 1. It is a great pleasure to acknowledge stimulating and instructive discussions with Sterl Phinney, Lee Lindblom, Kip Thorne, Ethan Vishniac and Roger Blandford. I am greatly indebted to the Theoretical Astrophysics and Relativity Group at Caltech for their hospitality and to Don Juan's teachings: '… because the warrior, having chosen a path, has but one goal: to traverse its full length’.
Subject Keywords:black hole physics – gravitational waves – instabilities – MHD
Issue or Number:2
Record Number:CaltechAUTHORS:20170408-205753601
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Official Citation:Rafael A. Araya-Góchez; Gravitational waves from hyper-accretion on to nascent black holes, Monthly Notices of the Royal Astronomical Society, Volume 355, Issue 2, 1 December 2004, Pages 336–344,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:76395
Deposited By: 1Science Import
Deposited On:30 Mar 2018 23:46
Last Modified:15 Nov 2021 16:59

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