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Does a "stochastic" background of gravitational waves exist in the pulsar timing band?

Ravi, V. and Wyithe, J. S. B. and Hobbs, G. and Shannon, R. M. and Manchester, R. N. and Yardley, D. R. B. and Keith, M. J. (2012) Does a "stochastic" background of gravitational waves exist in the pulsar timing band? Astrophysical Journal, 761 (2). Art. No. 84. ISSN 0004-637X. doi:10.1088/0004-637x/761/2/84.

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We investigate the effects of gravitational waves (GWs) from a simulated population of binary supermassive black holes (SMBHs) on pulsar timing array data sets. We construct a distribution describing the binary SMBH population from an existing semi-analytic galaxy formation model. Using realizations of the binary SMBH population generated from this distribution, we simulate pulsar timing data sets with GW-induced variations. We find that the statistics of these variations do not correspond to an isotropic, stochastic GW background. The "Hellings & Downs" correlations between simulated data sets for different pulsars are recovered on average, though the scatter of the correlation estimates is greater than expected for an isotropic, stochastic GW background. These results are attributable to the fact that just a few GW sources dominate the GW-induced variations in every Fourier frequency bin of a five-year data set. Current constraints on the amplitude of the GW signal from binary SMBHs will be biased. Individual binary systems are likely to be detectable in five-year pulsar timing array data sets where the noise is dominated by GW-induced variations. Searches for GWs in pulsar timing array data therefore need to account for the effects of individual sources of GWs.

Item Type:Article
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URLURL TypeDescription Paper
Ravi, V.0000-0002-7252-5485
Additional Information:© 2012 The American Astronomical Society. Received 2012 August 10; accepted 2012 October 11; published 2012 November 27. V.R. is a recipient of a John Stocker Postgraduate Scholarship from the Science and Industry Endowment Fund. J.S.B.W. acknowledges an Australian Research Council Laureate Fellowship. G.H. is the recipient of an Australian Research Council QEII Fellowship (project DP0878388). The Millennium and Millennium-II Simulation databases used in this paper and the web application providing online access to them were constructed as part of the activities of the German Astrophysical Virtual Observatory. We acknowledge use of the mpfit IDL routines of C. B. Markwardt. We thank W. Coles for his extensive and insightful comments into draft versions of the manuscript. We also thank the anonymous referee for comments that were useful in improving the manuscript.
Funding AgencyGrant Number
Science and Industry Endowment FundUNSPECIFIED
Australian Research CouncilDP0878388
Subject Keywords:black hole physics – galaxies: evolution – gravitational waves – methods: data analysis
Issue or Number:2
Record Number:CaltechAUTHORS:20190621-140739565
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Official Citation:V. Ravi et al 2012 ApJ 761 84
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:96632
Deposited By: Tony Diaz
Deposited On:23 Jun 2019 14:26
Last Modified:16 Nov 2021 17:22

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