The International Pulsar Timing Array second data release: Search for an isotropic gravitational wave background

Authors

• J. Antoniadis, Foundation for Research and Technology-Hellas
• Z. Arzoumanian, NASA Goddard Space Flight Center
• S. Babak, Université Paris Cité
• M. Bailes, Swinburne University of Technology
• A.-S. Bak Nielsen, Max Planck Institute for Radio Astronomy
• P. T. Baker, Widener University
• C. G. Bassa, Netherlands Foundation for Research in Astronomy
• B. Bécsy, Montana State University
• A. Berthereau, Université d'Orléans
• M. Bonetti, Università degli Studi di Milano-Bicocca
• A. Brazier, Cornell Center for Astrophysics and Planetary Science
• P. R. Brook, West Virginia University
• M. Burgay, Osservatorio Astronomico di Cagliari
• S. Burke-Spolaor, West Virginia University
• R. N. Caballero, Peking University
• J. A. Casey-Clyde, University of Connecticut
• A. Chalumeau, Université Paris Cité
• D. J. Champion, Max Planck Institute for Radio Astronomy
• M. Charisi, Vanderbilt University
• S. Chatterjee, Cornell Center for Astrophysics and Planetary Science
• S. Chen, Université d'Orléans
• I. Cognard, Université d'Orléans
• D. R. Madison, University of the PacificFollow

Document Type

Article

Publication Title

Monthly Notices of the Royal Astronomical Society

Department

Physics

ISSN

13652966

Volume

510

Issue

4

DOI

10.1093/mnras/stab3418

First Page

4873

Last Page

4887

Publication Date

1-19-2022

Abstract

We searched for an isotropic stochastic gravitational wave background in the second data release of the International Pulsar Timing Array, a global collaboration synthesizing decadal-length pulsar-timing campaigns in North America, Europe, and Australia. In our reference search for a power-law strain spectrum of the form hc = A(f/1, yr-α, we found strong evidence for a spectrally similar low-frequency stochastic process of amplitude A = 3.8+6.3-2.5 × 10-15 and spectral index α =-0.5 ± 0.5, where the uncertainties represent 95 per cent credible regions, using information from the auto- A nd cross-correlation terms between the pulsars in the array. For a spectral index of α =-2/3, as expected from a population of inspiralling supermassive black hole binaries, the recovered amplitude is A = 2.8+1.2-0.8 × 10-15. None the less, no significant evidence of the Hellings-Downs correlations that would indicate a gravitational-wave origin was found. We also analysed the constituent data from the individual pulsar timing arrays in a consistent way, and clearly demonstrate that the combined international data set is more sensitive. Furthermore, we demonstrate that this combined data set produces comparable constraints to recent single-array data sets which have more data than the constituent parts of the combination. Future international data releases will deliver increased sensitivity to gravitational wave radiation, and significantly increase the detection probability.

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

Recommended Citation

Antoniadis, J.; Arzoumanian, Z.; Babak, S.; Bailes, M.; Bak Nielsen, A.-S.; Baker, P. T.; Bassa, C. G.; Bécsy, B.; Berthereau, A.; Bonetti, M.; Brazier, A.; Brook, P. R.; Burgay, M.; Burke-Spolaor, S.; Caballero, R. N.; Casey-Clyde, J. A.; Chalumeau, A.; Champion, D. J.; Charisi, M.; Chatterjee, S.; Chen, S.; Cognard, I.; and Madison, D. R., "The International Pulsar Timing Array second data release: Search for an isotropic gravitational wave background" (2022). Pacific Faculty Work. 209.
https://scholarlycommons.pacific.edu/all-faculty/209