Finite distance effects on the Hellings–Downs curve in modified gravity

Publikation: Beitrag in FachzeitschriftArtikelForschungPeer-Review

Autorschaft

  • Guillem Domènech
  • Apostolos Tsabodimos

Organisationseinheiten

Externe Organisationen

  • Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut)
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Details

OriginalspracheEnglisch
Aufsatznummer1005
FachzeitschriftEuropean Physical Journal C
Jahrgang84
Ausgabenummer10
PublikationsstatusVeröffentlicht - 7 Okt. 2024

Abstract

There is growing interest in the overlap reduction function in pulsar timing array observations as a probe of modified gravity. However, current approximations to the Hellings–Downs curve for subluminal gravitational wave propagation, say v<1, diverge at small angular pulsar separation. In this paper, we find that the overlap reduction function for the v<1 case is sensitive to finite distance effects. First, we show that finite distance effects introduce an effective cut-off in the spherical harmonics decomposition at ℓ∼1-v2kL, where ℓ is the multipole number, k the wavenumber of the gravitational wave and L the distance to the pulsars. Then, we find that the overlap reduction function in the small angle limit approaches a value given by πkLv2(1-v2)2 times a normalization factor, exactly matching the value for the autocorrelation recently derived. Although we focus on the v<1 case, our formulation is valid for any value of v.

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Finite distance effects on the Hellings–Downs curve in modified gravity. / Domènech, Guillem; Tsabodimos, Apostolos.
in: European Physical Journal C, Jahrgang 84, Nr. 10, 1005, 07.10.2024.

Publikation: Beitrag in FachzeitschriftArtikelForschungPeer-Review

Domènech G, Tsabodimos A. Finite distance effects on the Hellings–Downs curve in modified gravity. European Physical Journal C. 2024 Okt 7;84(10):1005. doi: 10.1140/epjc/s10052-024-13418-w, 10.1140/epjc/s10052-024-13492-0
Domènech, Guillem ; Tsabodimos, Apostolos. / Finite distance effects on the Hellings–Downs curve in modified gravity. in: European Physical Journal C. 2024 ; Jahrgang 84, Nr. 10.
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