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Title: Detecting a gravitational-wave background with next-generation space interferometers

Abstract

Future missions of gravitational-wave astronomy will be operated by space-based interferometers, covering a very wide range of frequencies. Search for stochastic gravitational-wave backgrounds (GWBs) is one of the main targets for such missions, and we here discuss the prospects for direct measurement of isotropic and anisotropic components of (primordial) GWBs around the frequency 0.1-10 Hz. After extending the theoretical basis for correlation analysis, we evaluate the sensitivity and the signal-to-noise ratio for the proposed future space interferometer missions, like Big-Bang Observer (BBO), Deci-Hertz Interferometer Gravitational-wave Observer (DECIGO), and the recently proposed Fabry-Perot type DECIGO. The astrophysical foregrounds which are expected at low frequency may be a big obstacle and may significantly reduce the signal-to-noise ratio of GWBs. As a result, the minimum detectable amplitude may reach h{sup 2}{omega}{sub gw}=10{sup -15}{approx}10{sup -16}, as long as foreground point sources are properly subtracted. Based on correlation analysis, we also discuss measurement of anisotropies of GWBs. As an example, the sensitivity level required for detecting the dipole moment of GWB induced by the proper motion of our local system is closely examined.

Authors:
; ;  [1];  [2]
  1. Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan)
  2. Research Center for the Early Universe (RESCEU), School of Science, University of Tokyo, Tokyo 113-0033 (Japan)
Publication Date:
OSTI Identifier:
20782640
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 73; Journal Issue: 6; Other Information: DOI: 10.1103/PhysRevD.73.064006; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; AMPLITUDES; ANISOTROPY; CORRELATIONS; COSMOLOGY; DIPOLE MOMENTS; GRAVITATIONAL WAVES; INTERFEROMETERS; POINT SOURCES; PROPER MOTION; SENSITIVITY; SIGNAL-TO-NOISE RATIO; SPACE

Citation Formats

Kudoh, Hideaki, Hiramatsu, Takashi, Himemoto, Yoshiaki, and Taruya, Atsushi. Detecting a gravitational-wave background with next-generation space interferometers. United States: N. p., 2006. Web. doi:10.1103/PHYSREVD.73.064006.
Kudoh, Hideaki, Hiramatsu, Takashi, Himemoto, Yoshiaki, & Taruya, Atsushi. Detecting a gravitational-wave background with next-generation space interferometers. United States. doi:10.1103/PHYSREVD.73.064006.
Kudoh, Hideaki, Hiramatsu, Takashi, Himemoto, Yoshiaki, and Taruya, Atsushi. Wed . "Detecting a gravitational-wave background with next-generation space interferometers". United States. doi:10.1103/PHYSREVD.73.064006.
@article{osti_20782640,
title = {Detecting a gravitational-wave background with next-generation space interferometers},
author = {Kudoh, Hideaki and Hiramatsu, Takashi and Himemoto, Yoshiaki and Taruya, Atsushi},
abstractNote = {Future missions of gravitational-wave astronomy will be operated by space-based interferometers, covering a very wide range of frequencies. Search for stochastic gravitational-wave backgrounds (GWBs) is one of the main targets for such missions, and we here discuss the prospects for direct measurement of isotropic and anisotropic components of (primordial) GWBs around the frequency 0.1-10 Hz. After extending the theoretical basis for correlation analysis, we evaluate the sensitivity and the signal-to-noise ratio for the proposed future space interferometer missions, like Big-Bang Observer (BBO), Deci-Hertz Interferometer Gravitational-wave Observer (DECIGO), and the recently proposed Fabry-Perot type DECIGO. The astrophysical foregrounds which are expected at low frequency may be a big obstacle and may significantly reduce the signal-to-noise ratio of GWBs. As a result, the minimum detectable amplitude may reach h{sup 2}{omega}{sub gw}=10{sup -15}{approx}10{sup -16}, as long as foreground point sources are properly subtracted. Based on correlation analysis, we also discuss measurement of anisotropies of GWBs. As an example, the sensitivity level required for detecting the dipole moment of GWB induced by the proper motion of our local system is closely examined.},
doi = {10.1103/PHYSREVD.73.064006},
journal = {Physical Review. D, Particles Fields},
number = 6,
volume = 73,
place = {United States},
year = {Wed Mar 15 00:00:00 EST 2006},
month = {Wed Mar 15 00:00:00 EST 2006}
}
  • We show that an isotropic component of circular polarization of a stochastic gravitational wave background can be explored by contriving configuration of multiple laser interferometers for correlation analysis. For the proposed BBO mission, the circular polarization degree {pi} can be measured down to {pi}{approx}0.08({omega}{sub GW}/10{sup -15}){sup -1}(SNR/5) with slightly ({approx}10%) sacrificing the detection limit for the total intensity {omega}{sub GW}. This might allow us to detect a signature of parity violation in the very early universe.
  • This article derives an optimal (i.e., unbiased, minimum variance) estimator for the pseudodetector strain for a pair of colocated gravitational wave interferometers (such as the pair of LIGO interferometers at its Hanford Observatory), allowing for possible instrumental correlations between the two detectors. The technique is robust and does not involve any assumptions or approximations regarding the relative strength of gravitational wave signals in the Hanford pair with respect to other sources of correlated instrumental or environmental noise. An expression is given for the effective power spectral density of the combined noise in the pseudodetector. This can then be introduced intomore » the standard optimal Wiener filter used to cross-correlate detector data streams in order to obtain an optimal estimate of the stochastic gravitational wave background. In addition, a dual to the optimal estimate of strain is derived. This dual is constructed to contain no gravitational wave signature and can thus be used as an 'off-source' measurement to test algorithms used in the 'on-source' observation.« less
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