462 research outputs found
Assessing the Energetics of Spinning Binary Black Hole Systems
In this work we study the dynamics of spinning binary black hole systems in
the strong field regime. For this purpose we extract from numerical relativity
simulations the binding energy, specific orbital angular momentum, and
gauge-invariant orbital frequency. The goal of our work is threefold: First, we
extract the individual spin contributions to the binding energy, in particular
the spin-orbit, spin-spin, and cubic-in-spin terms. Second, we compare our
results with predictions from waveform models and find that while
post-Newtonian approximants are not capable of representing the dynamics during
the last few orbits before merger, there is good agreement between our data and
effective-one-body approximants as well as the numerical relativity surrogate
models. Finally, we present phenomenological representations for the binding
energy for non-spinning systems with mass ratios up to and for the
spin-orbit interaction for mass ratios up to obtaining accuracies of
and , respectively
Distinguishing Boson Stars from Black Holes and Neutron Stars from Tidal Interactions in Inspiraling Binary Systems
Binary systems containing boson stars---self-gravitating configurations of a
complex scalar field--- can potentially mimic black holes or neutron stars as
gravitational-wave sources. We investigate the extent to which tidal effects in
the gravitational-wave signal can be used to discriminate between these
standard sources and boson stars. We consider spherically symmetric boson stars
within two classes of scalar self-interactions: an
effective-field-theoretically motivated quartic potential and a solitonic
potential constructed to produce very compact stars. We compute the tidal
deformability parameter characterizing the dominant tidal imprint in the
gravitational-wave signals for a large span of the parameter space of each
boson star model. We find that the tidal deformability for boson stars with a
quartic self-interaction is bounded below by and
for those with a solitonic interaction by .
Employing a Fisher matrix analysis, we estimate the precision with which
Advanced LIGO and third-generation detectors can measure these tidal parameters
using the inspiral portion of the signal. We discuss a new strategy to improve
the distinguishability between black holes/neutrons stars and boson stars by
combining deformability measurements of each compact object in a binary system,
thereby eliminating the scaling ambiguities in each boson star model. Our
analysis shows that current-generation detectors can potentially distinguish
boson stars with quartic potentials from black holes, as well as from
neutron-star binaries if they have either a large total mass or a large mass
ratio. Discriminating solitonic boson stars from black holes using only tidal
effects during the inspiral will be difficult with Advanced LIGO, but
third-generation detectors should be able to distinguish between binary black
holes and these binary boson stars.Comment: 18 pages, 8 figures. Submitted to Physical Review
Improvements to the construction of binary black hole initial data
Construction of binary black hole initial data is a prerequisite for
numerical evolutions of binary black holes. This paper reports improvements to
the binary black hole initial data solver in the Spectral Einstein Code, to
allow robust construction of initial data for mass-ratio above 10:1, and for
dimensionless black hole spins above 0.9, while improving efficiency for lower
mass-ratios and spins. We implement a more flexible domain decomposition,
adaptive mesh refinement and an updated method for choosing free parameters. We
also introduce a new method to control and eliminate residual linear momentum
in initial data for precessing systems, and demonstrate that it eliminates
gravitational mode mixing during the evolution. Finally, the new code is
applied to construct initial data for hyperbolic scattering and for binaries
with very small separation.Comment: 28 pages, 13 figures, 1 tabl
Enriching the Symphony of Gravitational Waves from Binary Black Holes by Tuning Higher Harmonics
For the first time, we construct an inspiral-merger-ringdown waveform model
within the effective-one-body formalism for spinning, nonprecessing binary
black holes that includes gravitational modes beyond the dominant mode, specifically . Our multipolar
waveform model incorporates recent (resummed) post-Newtonian results for the
inspiral and information from 157 numerical-relativity simulations, and 13
waveforms from black-hole perturbation theory for the (plunge-)merger and
ringdown. We quantify the improved accuracy including higher-order modes by
computing the faithfulness of the waveform model against the
numerical-relativity waveforms used to construct the model. We define the
faithfulness as the match maximized over time, phase of arrival,
gravitational-wave polarization and sky position of the waveform model, and
averaged over binary orientation, gravitational-wave polarization and sky
position of the numerical-relativity waveform. When the waveform model contains
only the mode, we find that the averaged faithfulness to
numerical-relativity waveforms containing all modes with 5 ranges
from to for binaries with total mass (using
the Advanced LIGO's design noise curve). By contrast, when the
modes are also included in the model, the
faithfulness improves to for all but four configurations in the
numerical-relativity catalog, for which the faithfulness is greater than
. Using our results, we also develop also a (stand-alone) waveform
model for the merger-ringdown signal, calibrated to numerical-relativity
waveforms, which can be used to measure multiple quasi-normal modes. The
multipolar waveform model can be extended to include spin-precession, and will
be employed in upcoming observing runs of Advanced LIGO and Virgo.Comment: 28 page
Comparing Post-Newtonian and Numerical-Relativity Precession Dynamics
Binary black-hole systems are expected to be important sources of
gravitational waves for upcoming gravitational-wave detectors. If the spins are
not colinear with each other or with the orbital angular momentum, these
systems exhibit complicated precession dynamics that are imprinted on the
gravitational waveform. We develop a new procedure to match the precession
dynamics computed by post-Newtonian (PN) theory to those of numerical binary
black-hole simulations in full general relativity. For numerical relativity NR)
simulations lasting approximately two precession cycles, we find that the PN
and NR predictions for the directions of the orbital angular momentum and the
spins agree to better than with NR during the inspiral,
increasing to near merger. Nutation of the orbital plane on the
orbital time-scale agrees well between NR and PN, whereas nutation of the spin
direction shows qualitatively different behavior in PN and NR. We also examine
how the PN equations for precession and orbital-phase evolution converge with
PN order, and we quantify the impact of various choices for handling partially
known PN terms
Detectability and parameter estimation of GWTC-3 events with LISA
Multiband observations of coalescing stellar-mass black holes binaries could deliver valuable information on the formation of those sources and potential deviations from General Relativity. Some of these binaries might be first detected by the space-based detector LISA and, then, several years later, observed with ground-based detectors. Due to large uncertainties in astrophysical models, it is hard to predict the population of such binaries that LISA could observe. In this work, we assess the ability of LISA to detect the events of the third catalogue of gravitational wave sources released by the LIGO/Virgo/KAGRA collaboration. We consider the possibility of directly detecting the source with LISA and performing archival searches in the LISA data stream, after the event has been observed with ground-based detectors. We also assess how much could LISA improve the determination of source parameters. We find that it is not guaranteed that any event other than GW150914 would have been detected. Nevertheless, if any event is detected by LISA, even with a very low signal-to-noise ratio, the measurement of source parameters would improve by combining observations of LISA and ground based detectors, in particular for the chirp mass
Detectability and parameter estimation of GWTC-3 events with LISA
Multiband observations of coalescing stellar-mass black holes binaries could
deliver valuable information on the formation of those sources and potential
deviations from General Relativity. Some of these binaries might be first
detected by the space-based detector LISA and, then, several years later,
observed with ground-based detectors. Due to large uncertainties in
astrophysical models, it is hard to predict the population of such binaries
that LISA could observe. In this work, we assess the ability of LISA to detect
the events of the third catalogue of gravitational wave sources released by the
LIGO/Virgo/KAGRA collaboration. We consider the possibility of directly
detecting the source with LISA and performing archival searches in the LISA
data stream, after the event has been observed with ground-based detectors. We
also assess how much could LISA improve the determination of source parameters.
We find that it is not guaranteed that any event other than GW150914 would have
been detected. Nevertheless, if any event is detected by LISA, even with a very
low signal-to-noise ratio, the measurement of source parameters would improve
by combining observations of LISA and ground based detectors, in particular for
the chirp mass.Comment: 10 pages, 11 figure
Fast post-adiabatic waveforms in the time domain: Applications to compact binary coalescences in LIGO and Virgo
We present a computationally efficient (time-domain) multipolar waveform model for quasi-circular spin-aligned compact binary coalescences. The model combines the advantages of the numerical-relativity informed, effective-one-body (EOB) family of models with a post-adiabatic solution of the equations of motion for the inspiral part of the two-body dynamics. We benchmark this model against other state-of-the-art waveforms in terms of efficiency and accuracy. We find a speed-up of one to two orders of magnitude compared to the underlying time-domain EOB model for the total mass range . More specifically, for a low total-mass system, such as a binary neutron star with equal masses of , like GW170817, the computational speedup is around 100 times; for an event with total mass and mass ratio , like GW190412, the speedup is by a factor of , while for a binary system of comparable masses and total mass of , like GW150914, it is by a factor of . We demonstrate that the new model is extremely faithful to the underlying EOB model with unfaithfulness less than across the entire applicable region of parameter space. Finally, we present successful applications of this new waveform model to parameter estimation studies and tests of general relativity
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