48 research outputs found
Detection of gravitational-wave bursts with chirplet-like template families
Gravitational Wave (GW) burst detection algorithms typically rely on the
hypothesis that the burst signal is "locally stationary", that is it changes
slowly with frequency. Under this assumption, the signal can be decomposed into
a small number of wavelets with constant frequency. This justifies the use of a
family of sine-Gaussian templates in the Omega pipeline, one of the algorithms
used in LIGO-Virgo burst searches. However there are plausible scenarios where
the burst frequency evolves rapidly, such as in the merger phase of a binary
black hole and/or neutron star coalescence. In those cases, the local
stationarity of sine-Gaussians induces performance losses, due to the mismatch
between the template and the actual signal. We propose an extension of the
Omega pipeline based on chirplet-like templates. Chirplets incorporate an
additional parameter, the chirp rate, to control the frequency variation. In
this paper, we show that the Omega pipeline can easily be extended to include a
chirplet template bank. We illustrate the method on a simulated data set, with
a family of phenomenological binary black-hole coalescence waveforms embedded
into Gaussian LIGO/Virgo-like noise. Chirplet-like templates result in an
enhancement of the measured signal-to-noise ratio.Comment: 8 pages, 6 figures. Submitted to Class. Quantum Grav. Special issue:
Proceedings of GWDAW-14, Rome (Italy), 2010; fixed several minor issue
Exploring the Use of Numerical Relativity Waveforms in Burst Analysis of Precessing Black Hole Mergers
Recent years have witnessed tremendous progress in numerical relativity and
an ever improving performance of ground-based interferometric gravitational
wave detectors. In preparation for Advanced LIGO and a new era in gravitational
wave astronomy, the numerical relativity and gravitational wave data analysis
communities are collaborating to ascertain the most useful role for numerical
relativity waveforms in the detection and characterization of binary black hole
coalescences. In this paper, we explore the detectability of equal mass,
merging black hole binaries with precessing spins and total mass M_T in
[80,350]Msol, using numerical relativity waveforms and template-less search
algorithms designed for gravitational wave bursts. In particular, we present a
systematic study using waveforms produced by the MAYAKRANC code that are added
to colored, Gaussian noise and analyzed with the Omega burst search algorithm.
Detection efficiency is weighed against the orientation of one of the
black-hole's spin axes. We find a strong correlation between the detection
efficiency and the radiated energy and angular momentum, and that the inclusion
of the l=2, m=+/-1,0 modes, at a minimum, is necessary to account for the full
dynamics of precessing systems.Comment: 9 pages, 15 figure
Performance of a Chirplet-based analysis for gravitational waves from binary black hole mergers
The gravitational wave (GW) signature of a binary black hole (BBH)
coalescence is characterized by rapid frequency evolution in the late inspiral
and merger phases. For a system with total mass larger than 100 M_sun, ground
based GW detectors are sensitive to the merger phase, and the in-band whitened
waveform is a short-duration transient lasting about 10-30 ms. For a symmetric
mass system with total mass between 10 and 100 M_sun, the detector is sensitive
instead to the inspiral phase and the in-band signal has a longer duration,
between 30 ms - 3 s. Omega is a search algorithm for GW bursts that, with the
assumption of locally stationary frequency evolution, uses sine-Gaussian
wavelets as a template bank to decompose interferometer strain data. The local
stationarity of sine-Gaussians induces a performance loss for the detection of
lower mass BBH signatures, due to the mismatch between template and signal. We
present the performance of a modified version of the Omega algorithm, Chirplet
Omega, which allows a linear variation of frequency, to target BBH
coalescences. The use of Chirplet-like templates enhances the measured
signal-to-noise ratio due to less mismatch between template and data, and
increases the detectability of lower mass BBH coalescences. We present the
results of a performance study of Chirplet Omega in colored Gaussian noise at
initial LIGO sensitivity.Comment: 7 pages, 12 figures. Proceedings of Amaldi-9, Cardiff (UK), 201
Sensitivity Comparison of Searches for Binary Black Hole Coalescences with Ground-based Gravitational-Wave Detectors
Searches for gravitational-wave transients from binary black hole
coalescences typically rely on one of two approaches: matched filtering with
templates and morphology-independent excess power searches. Multiple
algorithmic implementations in the analysis of data from the first generation
of ground-based gravitational wave interferometers have used different
strategies for the suppression of non-Gaussian noise transients, and targeted
different regions of the binary black hole parameter space. In this paper we
compare the sensitivity of three such algorithms: matched filtering with full
coalescence templates, matched filtering with ringdown templates and a
morphology-independent excess power search. The comparison is performed at a
fixed false alarm rate and relies on Monte-carlo simulations of binary black
hole coalescences for spinning, non-precessing systems with total mass 25-350
solar mass, which covers the parameter space of stellar mass and intermediate
mass black hole binaries. We find that in the mass range of 25 -100 solar mass
the sensitive distance of the search, marginalized over source parameters, is
best with matched filtering to full waveform templates, to within 10 percent at
a false alarm rate of 3 events per year. In the mass range of 100-350 solar
mass, the same comparison favors the morphology-independent excess power search
to within 20 percent. The dependence on mass and spin is also explored.Comment: 11 pages, 2 tables, 25 figure
Reconstructing gravitational wave signals from binary black hole mergers with minimal assumptions
We present a systematic comparison of the binary black hole (BBH) signal waveform reconstructed by two independent and complementary approaches used in LIGO and Virgo source inference: a template-based analysis, and a morphology-independent analysis. We apply the two approaches to real events and to two sets of simulated observations made by adding simulated BBH signals to LIGO and Virgo detector noise. The first set is representative of the 10 BBH events in the first Gravitational Wave Transient Catalog (GWTC-1). The second set is constructed from a population of BBH systems with total mass and signal strength in the ranges that ground based detectors are typically sensitive. We find that the reconstruction quality of the GWTC-1 events is consistent with the results of both sets of simulated signals. We also demonstrate a simulated case where the presence of a mismodelled effect in the observed signal, namely higher order modes, can be identified through the morphology-independent analysis. This study is relevant for currently progressing and future observational runs by LIGO and Virgo
Characterizing the efficacy of methods to subtract terrestrial transient noise near gravitational wave events and the effects on parameter estimation
We investigate the impact of transient noise artifacts, or {\it glitches}, on
gravitational wave inference, and the efficacy of data cleaning procedures in
recovering unbiased source properties. Due to their time-frequency morphology,
broadband glitches demonstrate moderate to significant biasing of posterior
distributions away from true values. In contrast, narrowband glitches have
negligible biasing effects owing to distinct signal and glitch morphologies. We
inject simulated binary black hole signals into data containing three common
glitch types from past LIGO-Virgo observing runs, and reconstruct both signal
and glitch waveforms using {\tt BayesWave}, a wavelet-based Bayesian analysis.
We apply the standard LIGO-Virgo-KAGRA deglitching procedure to the detector
data - we subtract the glitch waveform estimated by the joint {\tt BayesWave}
inference before performing parameter estimation with detailed compact binary
waveform models. We find that this deglitching effectively mitigates bias from
broadband glitches, with posterior peaks aligning with true values post
deglitching. This provides a baseline validation of existing techniques, while
demonstrating waveform reconstruction improvements to the Bayesian algorithm
for robust astrophysical characterization in glitch-prone detector data.Comment: 22 pages, 17 figure
Plans for the LIGO-TAMA Joint Search for Gravitational Wave Bursts
We describe the plans for a joint search for unmodelled gravitational wave
bursts being carried out by the LIGO and TAMA collaborations using data
collected during February-April 2003. We take a conservative approach to
detection, requiring candidate gravitational wave bursts to be seen in
coincidence by all four interferometers. We focus on some of the complications
of performing this coincidence analysis, in particular the effects of the
different alignments and noise spectra of the interferometers.Comment: Proceedings of the 8th Gravitational Wave Data Analysis Workshop,
Milwaukee, WI, USA. 10 pages, 3 figures, documentclass ``iopart'
Cosmogenic 11C production and sensitivity of organic scintillator detectors to pep and CNO neutrinos
Several possible background sources determine the detectability of pep and
CNO solar neutrinos in organic liquid scintillator detectors. Among such
sources, the cosmogenic 11C nuclide plays a central role. 11C is produced
underground in reactions induced by the residual cosmic muon flux. Experimental
data available for the effective cross section for 11C by muons indicate that
11C will be the dominant source of background for the observation of pep and
CNO neutrinos. 11C decays are expected to total a rate 2.5 (20) times higher
than the combined rate of pep and CNO neutrinos in Borexino (KamLAND) in the
energy window preferred for the pep measurement, between 0.8 and 1.3 MeV.
This study examines the production mechanism of 11C by muon-induced showers
in organic liquid scintillators with a novel approach: for the first time, we
perform a detailed ab initio calculation of the production of a cosmogenic
nuclide, 11C, taking into consideration all relevant production channels.
Results of the calculation are compared with the effective cross sections
measured by target experiments in muon beams.
This paper also discusses a technique for reduction of background from 11C in
organic liquid scintillator detectors, which allows to identify on a one-by-one
basis and remove from the data set a large fraction of 11C decays. The
background reduction technique hinges on an idea proposed by Martin Deutsch,
who suggested that a neutron must be ejected in every interaction producing a
11C nuclide from 12C. 11C events are tagged by a three-fold coincidence with
the parent muon track and the subsequent neutron capture on protons.Comment: 11 pages, 6 figures; added one section detailing comparison with
previous estimates; added reference