Measuring the Primordial Gravitational-Wave Background in the Presence of Astrophysical Foregrounds
Primordial gravitational waves are expected to create a stochastic background encoding information about the early Universe that may not be accessible by other means. However, the primordial background is obscured by an astrophysical foreground consisting of gravitational waves from compact binaries. We demonstrate a Bayesian method for estimating the primordial background in the presence of an astrophysical foreground. Since the background and foreground signal parameters are estimated simultaneously, there is no subtraction step, and therefore we avoid astrophysical contamination of the primordial measurement, sometimes referred to as "residuals." Additionally, since we include the non-Gaussianity of the astrophysical foreground in our model, this method represents the statistically optimal approach to the simultaneous detection of a multicomponent stochastic background.
© 2020 American Physical Society. Received 9 September 2020; accepted 30 October 2020; published 9 December 2020. The authors thank Jan Harms and Salvatore Vitale for thoughtful comments on the manuscript. S. B. and C. T. acknowledge support of the National Science Foundation and the LIGO Laboratory. LIGO was constructed by the California Institute of Technology and Massachusetts Institute of Technology with funding from the National Science Foundation and operates under cooperative agreement No. PHY-1764464. S. B. is also supported by the Paul and Daisy Soros Fellowship for New Americans, the Australian-American Fulbright Commission, and the NSF Graduate Research Fellowship under Grant No. DGE-1122374. E. T. and R. S. are supported by the Australian Research Council (ARC) CE170100004. E. T. is supported by ARC FT150100281. The authors are grateful for computation resources provided by the OzStar cluster. This article carries LIGO Document Number LIGO-P2000297.
Accepted Version - 2009.04418.pdf
Published - PhysRevLett.125.241101.pdf