https://doi.org/10.1140/epjc/s10052-023-12370-5
Regular Article - Theoretical Physics
Overlap reduction function for pulsar timing arrays in an expanding Universe
Department of Physics, Chongqing University, 401331, Chongqing, China
Received:
16
November
2023
Accepted:
17
December
2023
Published online:
4
January
2024
Since it was confirmed two decades ago that the expansion of the Universe is accelerating, it would be of theoretical interests to figure out what is the influence from cosmological constant on detection of stochastic gravitational wave background. This paper studies the overlap reduction functions in de-Sitter space-time for a pair of one-way tracking gravitational wave detectors. It is shown to be non-trivial in an expanding Universe, because the propagation of light along line of sight also has effect on the response of GW detectors. It is found that the expansion of the Universe can enhance the value of magnitude of the overlap reduction functions, when the detector pairs are close to each other. For nanohertz gravitational waves, this effect can dominate the values of overlap reduction functions when the galactic pulsar pairs are separated by milliarcsecond.
© The Author(s) 2024
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