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Upper Bounds on the Low-frequency Stochastic Gravitational Wave Background from Pulsar Timing Observations: Current Limits and Future Prospects

Citation

Jenet, FA and Hobbs, GB and van Straten, W and Manchester, RN and Bailes, M and Verbiest, JPW and Edwards, RT and Hotan, AW and Sarkissian, JM and Ord, SM, Upper Bounds on the Low-frequency Stochastic Gravitational Wave Background from Pulsar Timing Observations: Current Limits and Future Prospects, The Astrophysical Journal, 653, (2 I) pp. 1571-1576. ISSN 0004-637X (2006) [Refereed Article]

DOI: doi:10.1086/508702

Abstract

Using a statistically rigorous analysis method, we place limits on the existence of an isotropic stochastic gravitational wave background using pulsar timing observations. We consider backgrounds whose characteristic strain spectra may be described as a power-law dependence with frequency. Such backgrounds include an astrophysical background produced by coalescing supermassive black-hole binary systems and cosmological backgrounds due to relic gravitational waves and cosmic strings. Using the best available data, we obtain an upper limit on the energy density per unit logarithmic frequency interval of Ω g SMBH[1/(8 yr)}h 2 ≤ 1.9 × 10 -8 for an astrophysical background that is 5 times more stringent than the earlier limit of 1.1 × 10 -7 found by Kaspi and colleagues. We also provide limits on a background due to relic gravitational waves and cosmic strings of Ω g relic [1/(8 yr)]h 2 ≤ 2.0 × 10 -8 and Ω g cs [1/(8 yr)]h 2 ≤ 1.9 × 10 -8, respectively. All of the quoted upper limits correspond to a 0.1% false alarm rate together with a 95% detection rate. We discuss the physical implications of these results and highlight the future possibilities of the Parkes Pulsar Timing Array project. We find that our current results can (1) constrain the merger rate of supermassive binary black hole systems at high redshift, (2) rule out some relationships between the black hole mass and the galactic halo mass, (3) constrain the rate of expansion in the inflationary era, and (4) provide an upper bound on the dimensionless tension of a cosmic string background. © 2006. The American Astronomical Society. All rights reserved.

Item Details

Item Type:Refereed Article
Research Division:Physical Sciences
Research Group:Astronomical and Space Sciences
Research Field:Galactic Astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Physical Sciences
Author:Hotan, AW (Dr Aidan Hotan)
ID Code:45121
Year Published:2006
Web of Science® Times Cited:232
Deposited By:Physics
Deposited On:2007-07-03
Last Modified:2007-07-03
Downloads:0

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