25 research outputs found
Post-Newtonian templates for binary black-hole inspirals: the effect of the horizon fluxes and the secular change in the black-hole masses and spins
Black holes (BHs) in an inspiraling compact binary system absorb the
gravitational-wave (GW) energy and angular-momentum fluxes across their event
horizons and this leads to the secular change in their masses and spins during
the inspiral phase. The goal of this paper is to present ready-to-use, 3.5
post-Newtonian (PN) template families for spinning, non-precessing, binary BH
inspirals in quasicircular orbits, including the 2.5PN and 3.5PN horizon flux
contributions as well as the correction due to the secular change in the BH
masses and spins through 3.5PN order, respectively, in phase. We show that, for
binary BHs observable by Advanced LIGO with high mass ratio (larger than ~10)
and large aligned-spins (larger than ~0.7), the mismatch between the
frequency-domain template with and without the horizon-flux contribution is
typically above the 3% mark. For (supermassive) binary BHs observed by LISA,
even a moderate mass-ratios and spins can produce a similar level of the
mismatch. Meanwhile, the mismatch due to the secular time variations of the BH
masses and spins is well below the 1% mark in both cases, hence this is truly
negligible. We also point out that neglecting the cubic-in-spin, point-particle
phase term at 3.5PN order would deteriorate the effect of BH absorption in the
template.Comment: v3: 50 pages, 8 figures, matches the published versio
Cosmic censorship in overcharging a Reissner-Nordstr\"{o}m black hole via charged particle absorption
There is a claim that a static charged black hole (Reissner-Nordstr\"{o}m
black hole) can be overcharged by absorbing a charged test particle. If it is
true, it might give a counter example to the weak cosmic censorship conjecture,
which states that spacetime singularities are never observed by a distant
observer. However, so far the proposed process has only been analyzed within a
test particle approximation. Here we claim that the back reaction effects of a
charged particle cannot be neglected when judging whether the suggested process
is really a counter example to the cosmic censorship conjecture or not.
Furthermore, we argue that all the back reaction effects can be properly taken
into account when we consider the trajectory of a particle on the border
between the plunge and bounce orbits. In such marginal cases we find that the
Reissner-Nordstr\"{o}m black hole can never be overcharged via the absorption
of a charged particle. Since all the plunge orbits are expected to have a
higher energy than the marginal orbit, we conclude that there is no supporting
evidence that indicates the violation of the cosmic censorship in the proposed
overcharging process.Comment: 18 pages, revtex4, minor revision and reference added, version to
appear in PR
Scope out multiband gravitational-wave observations of GW190521-like binary black holes with space gravitational wave antenna B-DECIGO
The gravitational wave event, GW190521 is the most massive binary black hole
merger observed by ground-based gravitational wave observatories LIGO/Virgo to
date. While the observed gravitational-wave signal is mainly in the merger and
ringdown phases, the inspiral gravitational-wave signal of GW190521-like binary
will be more visible by space-based detectors in the low-frequency band. In
addition, the ringdown gravitational-wave signal will be more loud with the
next generation (3G) of ground-based detectors in the high-frequency band,
displaying a great potential of the multiband gravitational wave observations.
In this paper, we explore the scientific potential of multiband observations of
GW190521-like binaries with milli-Hz gravitational wave observatory: LISA,
deci-Hz observatory: B-DECIGO, and (next generation of) hecto-Hz observatories:
aLIGO and ET. In the case of quasicircular evolution, the triple-band
observation by LISA, B-DECIGO and ET will provide parameter estimation errors
of the masses and spin amplitudes of component black holes at the level of
order 1% -- 10%. This would allow consistency tests of general relativity in
the strong-field at an unparalleled precision, particularly with the "B-DECIGO
+ ET" observation. In the case of eccentric evolution, the multiband
signal-to-noise ratio by "B-DECIGO + ET" observation would be larger than 100
for a five year observation prior to coalescence, even with high final
eccentricities.Comment: 26 pages, 2 figures, accepted versio