Last orbit of binary black holes

Abstract

We have used our new technique for fully numerical evolutions of orbiting black-hole binaries without excision to model the last orbit and merger of an equal-mass black-hole system. We track the trajectories of the individual apparent horizons and find that the binary completed approximately one and a third orbits before forming a common horizon. Upon calculating the complete gravitational radiation waveform, horizon mass, and spin, we find that the binary radiated 3.2% of its mass and 24% of its angular momentum. The early part of the waveform, after a relatively short initial burst of spurious radiation, is oscillatory with increasing amplitude and frequency, as expected from orbital motion. The waveform then transitions to a typical 'plunge' waveform; i.e. a rapid rise in amplitude followed by quasinormal ringing. The plunge part of the waveform is remarkably similar to the waveform from the previously studied 'ISCO' configuration. We anticipate that the plunge waveform, when starting from quasicircular orbits, has a generic shape that is essentially independent of the initial separation of the binary.

Measuring orbital eccentricity and periastron advance in quasicircular black hole simulations

“…The late stage of the inspiral, corresponding to the final few orbits and merger of the binary, is highly dynamical and involves strong gravitational fields, and it must be handled by numerical relativity. Breakthroughs in numerical relativity have allowed a system of two inspiraling black holes to be evolved through merger and the ringdown of the remnant black hole [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15].…”

Unstable flip-flopping spinning binary black holes

“…These results implies that using (anti-)aligned spin models should remain a good approximation to more general systems for a large portion of the parameter space if the instability depletion is taken into account for quasiantialigned spins, since the main binary dynamical effect is dominated by the hangup [5] that depends on the spin components alongL.…”

“…The strongest dynamical effect of the spins on the orbit of BBH is the hangup effect [5], that depending on the spin components along the orbital angular momentum (aligned or counteraligned) delays or prompts the merger of BBH with respect to the nonspinning case.…”

Black hole evolution with the BSSN system by pseudospectral methods

“…As our numerical domain we use a spherical shell, which extends from R in = 1.85M to R out = 16M , with collocation points given by Eqs. (11)- (13). On this shell we will use the Chebyshev basis (8) in the radial direction and the Fourier basis (9) and (10) in the angular directions.…”

“…Nevertheless, the majority of the astrophysically relevant binary black hole simulations to date have used one particular combination: The BSSN evolution system together with finite differencing techniques. With this choice, several groups have recently performed binary black hole simulations of one orbit or more [10,11,12,13,14,15,16]. However, the BSSN system has never before been tested with a spectral method.…”