51 research outputs found
Efficient searches for spinning compact binaries with advanced gravitational-wave observatories
[no abstract
Designing a template bank to observe compact binary coalescences in Advanced LIGO's second observing run
We describe the methodology and novel techniques used to construct a set of
waveforms, or template bank, applicable to searches for compact binary
coalescences in Advanced LIGO's second observing run. This template bank is
suitable for observing systems composed of two neutron stars, two black holes,
or a neutron star and a black hole. The Post-Newtonian formulation is used to
model waveforms with total mass less than 4 and the most recent
effective-one-body model, calibrated to numerical relativity to include the
merger and ringdown, is used for total masses greater than 4 . The
effects of spin precession, matter, orbital eccentricity and radiation modes
beyond the quadrupole are neglected. In contrast to the template bank used to
search for compact binary mergers in Advanced LIGO's first observing run, here
we are including binary-black-hole systems with total mass up to several
hundreds of solar masses, thereby improving the ability to observe such
systems. We introduce a technique to vary the starting frequency of waveform
filters so that our bank can simultaneously contain binary-neutron-star and
high-mass binary-black hole waveforms. We also introduce a lower-bound on the
filter waveform length, to exclude very short-duration, high-mass templates
whose sensitivity is strongly reduced by the characteristics and performance of
the interferometers.Comment: 10 pages, 8 figure
PyCBC Live: Rapid Detection of Gravitational Waves from Compact Binary Mergers
We introduce an efficient and straightforward technique for rapidly detecting
gravitational waves from compact binary mergers. We show that this method
achieves the low latencies required to alert electromagnetic partners of
candidate binary mergers, aids in data monitoring, and makes use of
multidetector networks for sky localization. This approach was instrumental to
the analysis of gravitational-wave candidates during the second observing run
of Advanced LIGO, including the period of coincident operation with Advanced
Virgo, and in particular the analysis of the first observed binary neutron star
merger GW170817, where it led to the first tightly localized sky map
() used to identify AT 2017gfo. Operation of this analysis
also enabled the initial discovery of GW170104 and GW170608 despite non-nominal
observing of the instrument.Comment: 10 pages, 5 figures, submitted to Physical Review
Electromagnetic Chirps from Neutron Star-Black Hole Mergers
We calculate the electromagnetic signal of a gamma-ray flare coming from the
surface of a neutron star shortly before merger with a black hole companion.
Using a new version of the Monte Carlo radiation transport code Pandurata that
incorporates dynamic spacetimes, we integrate photon geodesics from the neutron
star surface until they reach a distant observer or are captured by the black
hole. The gamma-ray light curve is modulated by a number of relativistic
effects, including Doppler beaming and gravitational lensing. Because the
photons originate from the inspiraling neutron star, the light curve closely
resembles the corresponding gravitational waveform: a chirp signal
characterized by a steadily increasing frequency and amplitude. We propose to
search for these electromagnetic chirps using matched filtering algorithms
similar to those used in LIGO data analysis.Comment: 13 pages, 5 figures, submitted to Ap
Detecting binary compact-object mergers with gravitational waves: Understanding and Improving the sensitivity of the PyCBC search
We present an improved search for binary compact-object mergers using a
network of ground-based gravitational-wave detectors. We model a volumetric,
isotropic source population and incorporate the resulting distribution over
signal amplitude, time delay, and coalescence phase into the ranking of
candidate events. We describe an improved modeling of the background
distribution, and demonstrate incorporating a prior model of the binary mass
distribution in the ranking of candidate events. We find a and
increase in detection volume for simulated binary neutron star and
neutron star--binary black hole systems, respectively, corresponding to a
reduction of the false alarm rates assigned to signals by between one and two
orders of magnitude.Comment: 7 pages, 3 figures, as accepted by Ap
The PyCBC search for gravitational waves from compact binary coalescence
We describe the PyCBC search for gravitational waves from compact-object
binary coalescences in advanced gravitational-wave detector data. The search
was used in the first Advanced LIGO observing run and unambiguously identified
two black hole binary mergers, GW150914 and GW151226. At its core, the PyCBC
search performs a matched-filter search for binary merger signals using a bank
of gravitational-wave template waveforms. We provide a complete description of
the search pipeline including the steps used to mitigate the effects of noise
transients in the data, identify candidate events and measure their statistical
significance. The analysis is able to measure false-alarm rates as low as one
per million years, required for confident detection of signals. Using data from
initial LIGO's sixth science run, we show that the new analysis reduces the
background noise in the search, giving a 30% increase in sensitive volume for
binary neutron star systems over previous searches.Comment: 29 pages, 7 figures, accepted by Classical and Quantum Gravit
Gravitational waves: search results, data analysis and parameter estimation
The Amaldi 10 Parallel Session C2 on gravitational wave (GW) search results, data analysis and parameter estimation included three lively sessions of lectures by 13 presenters, and 34 posters. The talks and posters covered a huge range of material, including results and analysis techniques for ground-based GW detectors, targeting anticipated signals from different astrophysical sources: compact binary inspiral, merger and ringdown; GW bursts from intermediate mass binary black hole mergers, cosmic string cusps, core-collapse supernovae, and other unmodeled sources; continuous waves from spinning neutron stars; and a stochastic GW background. There was considerable emphasis on Bayesian techniques for estimating the parameters of coalescing compact binary systems from the gravitational waveforms extracted from the data from the advanced detector network. This included methods to distinguish deviations of the signals from what is expected in the context of General Relativity
- …