3 research outputs found
Gravitational Waves from Hyper-Accretion onto Nascent Black Holes
We examine the possibility that hyper-accretion onto newly born, black holes
occurs in highly intermittent, non-asymmetric fashion favorable to
gravitational wave emission in a neutrino cooled disk. This picture of
near-hole accretion is motivated by magneto-rotationally induced,
ultra-relativistic disk dynamics in the region of the flow bounded from below
by the marginally bound geodesic radius. 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, MRI modes.
When neutrino stress competes favorably for the disk dynamical structure, the
matter clumps may be rather dense and sufficiently long-lived to excite the
Quasi-Normal Ringing (a.k.a. QNR) modes of the Kerr geometry upon their
in-fall. We find that such accretion flow may drive bar-like, quadrupole
(l,m=2,2) modes in nearly resonant fashion for spin parameters . 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 \msun \sec^{-1}. Thus, a 15 \msun Kerr black hole
spinning at ( Hz), and located at 27
Mpc (e.g., GRB980425), will deliver a characteristic strain amplitude, , 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 GRB light-curve, these
objects could be detected by LIGO I at very low redshifts.Comment: 12 pages, 4 figures, M.N.R.A.S. submissio