417 research outputs found
Cosmic Background of Gravitational Waves from Rotating Neutron Stars
No full textaccepted for publication in Astronomy & AstrophysicsInternational audienceThe extragalactic background of gravitational waves produced by tri-axial rotating neutron stars was calculated, under the assumption that the properties of the underlying pulsar population are the same of those of the galactic population, recently derived by Regimbau & de Freitas Pacheco (2000). For an equatorial ellipticity of = 10, the equivalent density parameter due to gravitational waves has a maximum amplitude in the range 2, around 0.9-1.5 kHz. The main reasons affecting the theoretical predictions are discussed. This background is comparable to that produced by the ''ring-down'' emission from distorted black holes. The detection possibility of this background by a future generation of gravitational antennas is also examined
Prospects for stochastic background searches using Virgo and LSC interferometers
No full textWe consider the question of cross-correlation measurements using Virgo and
the LSC Interferometers (LIGO Livingston, LIGO Hanford and GEO600) to
search for a stochastic gravitational-wave background. We find that inclusion of
Virgo into the network will substantially improve the sensitivity to correlations
above 200 Hz if all detectors are operating at their design sensitivity. This is
illustrated using a simulated isotropic stochastic background signal, generated
with an astrophysically-motivated spectral shape, injected into 24 h of simulated
noise for the LIGO and Virgo interferometers
Deep learning searches for gravitational wave stochastic backgrounds
No full textThe background of gravitational waves (GW) has long been studied and remains one of the most exciting aspects in the observation and analysis of gravitational radiation. The paper focuses on the search for the background of gravitational waves using deep neural networks. An astrophysical background due to the presence of many binary black hole coalescences was simulated for Advanced LIGO O3 sensitivity and the Einstein Telescope (ET) design sensitivity. The detection pipeline targets signal data out of the noisy detector background. Its architecture comprises of simulated whitened data as input to three classes of deep neural networks algorithms: a 1D and a 2D convolutional neural network (CNN) and a Long Short Term Memory (LSTM) network. It was found that all three algorithms could distinguish signals from noise with high precision for the ET sensitivity, but the current sensitivity of LIGO is too low to permit the algorithms to learn signal features from the input vectors
Gravitational background from dynamical binaries and detectability with 2G detectors
No full textWe study the impact of young clusters on the gravitational wave background from compact binary coalescence. We simulate a catalog of sources from population I/II isolated binary stars and stars born in young clusters, corresponding to one year of observations with second-generation (2G) detectors. Taking into account uncertainties on the fraction of dynamical binaries and star formation parameters, we find that the background is dominated by the population of binary black holes, and we obtain a value of ωgw(25 Hz)=1.2-0.65+1.38×10-9 for the energy density, in agreement with the actual upper limits derived from the latest observation run of LIGO-Virgo. We demonstrate that a large number of sources in a specific corrected mass range yields to a bump in the background. This background could be detected with 8 years of coincident data by a network of 2G detectors
The astrophysical gravitational wave stochastic background
No full textInternational audienceA stochastic background of gravitational waves with astrophysical origins may have resulted from the superposition of a large number of unresolved sources since the beginning of stellar activity. Its detection would put very strong constraints on the physical properties of compact objects, the initial mass function and star formation history. On the other hand, it could be a ‘noise’ that would mask the stochastic background of its cosmological origin. We review the main astrophysical processes which are able to produce a stochastic background and discuss how they may differ from the primordial contribution in terms of statistical properties. Current detection methods are also presented
Continuous gravitational-wave data analysis with general purpose computing on graphic processing units
No full textWe present a new approach to searching for Continuous gravitational Waves (CWs) emitted by isolated rotating neutron stars, using the high parallel computing efficiency and computational power of modern Graphic Processing Units (GPUs). Specifically, in this paper the porting of one of the algorithms used to search for CW signals, the so-called FrequencyHough transform, on the TensorFlow framework, is described. The new code has been fully tested and its performance on GPUs has been compared to those in a CPU multicore system of the same class, showing a factor of 10 speed-up. This demonstrates that GPU programming with general purpose libraries (the those of the TensorFlow framework) of a high-level programming language can provide a significant improvement of the performance of data analysis, opening new perspectives on wide-parameter searches for CWs
Confusion background from compact binaries
No full textURL to conference site: http://www.amaldi8.org/index.htmlDouble neutron stars are one of the most promizing sources for terrestrial gravitational wave interferometers. For actual interferometers and their planned upgrades, the probability of having a signal present in the data is small, but as the sensitivity improves, the detection rate increases and the waveforms may start to overlap, creating a confusion background, ultimately limiting the capabilities of future detectors. The third generation Einstein Telescope, with an horizon of z > 1 and very low frequency "seismic wall" may be affected by such confusion noise. At a minimum, careful data analysis will be require to separate signals which will appear confused. This result should be borne in mind when designing highly advanced future instruments
Gravitational-wave confusion background from cosmological compact binaries: Implications for future terrestrial detectors
No full textIncreasing the sensitivity of a gravitational-wave (GW) detector improves our ability to measure the characteristics of detected sources. It also increases the number of weak signals that contribute to the data. Because GW detectors have nearly all-sky sensitivity, they can be subject to a confusion limit: Many sources which cannot be distinguished may be measured simultaneously, defining a stochastic noise floor to the sensitivity. For GW detectors operating at present and for their planned upgrades, the projected event rate is sufficiently low that we are far from the confusion-limited regime. However, some detectors currently under discussion may have large enough reach to binary inspiral that they enter the confusion-limited regime. In this paper, we examine the binary inspiral confusion limit for terrestrial detectors. We consider a broad range of inspiral rates in the literature, several planned advanced gravitational-wave detectors, and the highly advanced “Einstein telescope” design. Though most advanced detectors will not be impacted by this limit, the Einstein telescope with a very low-frequency “seismic wall” may be subject to confusion noise. At a minimum, careful data analysis will be require to separate signals which will appear confused. This result should be borne in mind when designing highly advanced future instruments.MIT Class of 1956 Career Development FundNASANational Science Foundatio
On the (In)Efficiency of the Cross-Correlation Statistic for Gravitational Wave Stochastic Background Signals with Non-Gaussian Noise and Heterogeneous Detector Sensitivities
No full textInternational audienc
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