161 research outputs found
Interpolating compact binary waveforms using the singular value decomposition
Compact binary systems with total masses between tens and hundreds of solar
masses will produce gravitational waves during their merger phase that are
detectable by second-generation ground-based gravitational-wave detectors. In
order to model the gravitational waveform of the merger epoch of compact binary
coalescence, the full Einstein equations must be solved numerically for the
entire mass and spin parameter space. However, this is computationally
expensive. Several models have been proposed to interpolate the results of
numerical relativity simulations. In this paper we propose a numerical
interpolation scheme that stems from the singular value decomposition. This
algorithm shows promise in allowing one to construct arbitrary waveforms within
a certain parameter space given a sufficient density of numerical simulations
covering the same parameter space. We also investigate how similar approaches
could be used to interpolate waveforms in the context of parameter estimation.Comment: 5 pages, 3 figures, presented at the joint 9th Edoardo Amaldi
Conference on Gravitational Waves and 2011 Numerical Relativity - Data
Analysis (NRDA) meetin
A method to estimate the significance of coincident gravitational-wave observations from compact binary coalescence
Coalescing compact binary systems consisting of neutron stars and/or black
holes should be detectable with upcoming advanced gravitational-wave detectors
such as LIGO, Virgo, GEO and {KAGRA}. Gravitational-wave experiments to date
have been riddled with non-Gaussian, non-stationary noise that makes it
challenging to ascertain the significance of an event. A popular method to
estimate significance is to time shift the events collected between detectors
in order to establish a false coincidence rate. Here we propose a method for
estimating the false alarm probability of events using variables commonly
available to search candidates that does not rely on explicitly time shifting
the events while still capturing the non-Gaussianity of the data. We present a
method for establishing a statistical detection of events in the case where
several silver-plated (3--5) events exist but not necessarily any
gold-plated () events. We use LIGO data and a simulated, realistic,
blind signal population to test our method
Interpolation in waveform space: enhancing the accuracy of gravitational waveform families using numerical relativity
Matched-filtering for the identification of compact object mergers in
gravitational-wave antenna data involves the comparison of the data stream to a
bank of template gravitational waveforms. Typically the template bank is
constructed from phenomenological waveform models since these can be evaluated
for an arbitrary choice of physical parameters. Recently it has been proposed
that singular value decomposition (SVD) can be used to reduce the number of
templates required for detection. As we show here, another benefit of SVD is
its removal of biases from the phenomenological templates along with a
corresponding improvement in their ability to represent waveform signals
obtained from numerical relativity (NR) simulations. Using these ideas, we
present a method that calibrates a reduced SVD basis of phenomenological
waveforms against NR waveforms in order to construct a new waveform approximant
with improved accuracy and faithfulness compared to the original
phenomenological model. The new waveform family is given numerically through
the interpolation of the projection coefficients of NR waveforms expanded onto
the reduced basis and provides a generalized scheme for enhancing
phenomenological models.Comment: 10 pages, 7 figure
LADEE Satellite Modeling and Simulation Development
As human activity on and around the Moon increases, so does the likelihood that our actions will have an impact on its atmosphere. The Lunar Atmosphere and Dust Environment Explorer (LADEE), a NASA satellite scheduled to launch in 2013, will orbit the Moon collecting composition, density, and time variability data to characterize the current state of the lunar atmosphere. LADEE will also test the concept of the "Modular Common Bus" spacecraft architecture, an effort to reduce both development time and cost by designing reusable, modular components for use in multiple missions with similar requirements. An important aspect of this design strategy is to both simulate the spacecraft and develop the flight code in Simulink, a block diagram-style programming language that allows easy algorithm visualization and performance testing. Before flight code can be tested, however, a realistic simulation of the satellite and its dynamics must be generated and validated. This includes all of the satellite control system components such as actuators used for force and torque generation and sensors used for inertial orientation reference. My primary responsibilities have included designing, integrating, and testing models for the LADEE thrusters, reaction wheels, star trackers, and rate gyroscopes
Application of a Zero-latency Whitening Filter to Compact Binary Coalescence Gravitational-wave Searches
Joint electromagnetic and gravitational-wave (GW) observation is a major goal
of both the GW astronomy and electromagnetic astronomy communities for the
coming decade. One way to accomplish this goal is to direct follow-up of GW
candidates. Prompt electromagnetic emission may fade quickly, therefore it is
desirable to have GW detection happen as quickly as possible. A leading source
of latency in GW detection is the whitening of the data. We examine the
performance of a zero-latency whitening filter in a detection pipeline for
compact binary coalescence (CBC) GW signals. We find that the filter reproduces
signal-to-noise ratio (SNR) sufficiently consistent with the results of the
original high-latency and phase-preserving filter for both noise and artificial
GW signals (called "injections"). Additionally, we demonstrate that these two
whitening filters show excellent agreement in value, a discriminator
for GW signals.Comment: 8 pages, 12 figure
Efficiently enclosing the compact binary parameter space by singular-value decomposition
Gravitational-wave searches for the merger of compact binaries use
matched-filtering as the method of detecting signals and estimating parameters.
Such searches construct a fine mesh of filters covering a signal parameter
space at high density. Previously it has been shown that singular value
decomposition can reduce the effective number of filters required to search the
data. Here we study how the basis provided by the singular value decomposition
changes dimension as a function of template bank density. We will demonstrate
that it is sufficient to use the basis provided by the singular value
decomposition of a low density bank to accurately reconstruct arbitrary points
within the boundaries of the template bank. Since this technique is purely
numerical it may have applications to interpolating the space of numerical
relativity waveforms.Comment: 5 pages, 6 figure
Singular value decomposition applied to compact binary coalescence gravitational-wave signals
We investigate the application of the singular value decomposition to
compact-binary, gravitational-wave data-analysis. We find that the truncated
singular value decomposition reduces the number of filters required to analyze
a given region of parameter space of compact binary coalescence waveforms by an
order of magnitude with high reconstruction accuracy. We also compute an
analytic expression for the expected signal-loss due to the singular value
decomposition truncation.Comment: 4 figures, 6 page
Second Einstein Telescope mock data and science challenge: Low frequency binary neutron star data analysis
The Einstein Telescope is a conceived third generation gravitational-wave
detector that is envisioned to be an order of magnitude more sensitive than
advanced LIGO, Virgo and Kagra, which would be able to detect
gravitational-wave signals from the coalescence of compact objects with
waveforms starting as low as 1Hz. With this level of sensitivity, we expect to
detect sources at cosmological distances. In this paper we introduce an
improved method for the generation of mock data and analyse it with a new low
latency compact binary search pipeline called gstlal. We present the results
from this analysis with a focus on low frequency analysis of binary neutron
stars. Despite compact binary coalescence signals lasting hours in the Einstein
Telescope sensitivity band when starting at 5 Hz, we show that we are able to
discern various overlapping signals from one another. We also determine the
detection efficiency for each of the analysis runs conducted and and show a
proof of concept method for estimating the number signals as a function of
redshift. Finally, we show that our ability to recover the signal parameters
has improved by an order of magnitude when compared to the results of the first
mock data and science challenge. For binary neutron stars we are able to
recover the total mass and chirp mass to within 0.5% and 0.05%, respectively
Composite gravitational-wave detection of compact binary coalescence
The detection of gravitational waves from compact binaries relies on a
computationally burdensome processing of gravitational-wave detector data. The
parameter space of compact-binary-coalescence gravitational waves is large and
optimal detection strategies often require nearly redundant calculations.
Previously, it has been shown that singular value decomposition of search
filters removes redundancy. Here we will demonstrate the use of singular value
decomposition for a composite detection statistic. This can greatly improve the
prospects for a computationally feasible rapid detection scheme across a large
compact binary parameter space.Comment: 6 pages, 3 figure
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