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arXiv · 2511.01919

Optimal strategies for continuous wave detection in pulsar timing arrays: Realistic pulsar noise and a gravitational wave background

Shashwat C. Sardesai·Gabriel E. Freedman·Sarah J. Vigeland·Caitlin A. Witt
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Abstract

Pulsar timing arrays are sensitive to low-frequency gravitational waves (GWs), such as those produced by supermassive binary black holes at subparsec separations. The incoherent superposition of GWs emitted by a cosmological population of these sources produces a gravitational wave background (GWB), while some individual sources may be resolvable as deterministic signals with slowly varying GW frequencies, which are often referred to as "continuous waves" (CWs). The Fp-statistic is a frequentist method of detecting these CWs. In this paper, we study how the presence of pulsar red noise and a GWB affect the Fp-statistic. We compare results when marginalizing over the red noise and using the maximum-likelihood values of the red noise, and find little difference between the two. We also present results of using the Fp-statistic to analyze the NANOGrav 12.5-year data set, where we find no evidence for CWs in agreement with the previously published Bayesian results.

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Shashwat C. Sardesai, Gabriel E. Freedman, Sarah J. Vigeland, Caitlin A. Witt. 2025-11-01. Optimal strategies for continuous wave detection in pulsar timing arrays: Realistic pulsar noise and a gravitational wave background. https://arxiv.org/abs/2511.01919

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