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Main Authors: Kumar, Neha Anil, Kamionkowski, Marc
Format: Preprint
Published: 2023
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Online Access:https://arxiv.org/abs/2311.14159
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author Kumar, Neha Anil
Kamionkowski, Marc
author_facet Kumar, Neha Anil
Kamionkowski, Marc
contents Pulsar timing arrays seek and study gravitational waves (GWs) through the angular two-point correlation function of timing residuals they induce in pulsars. The two-point correlation function induced by the standard transverse-traceless GWs is the famous Hellings-Downs curve, a function only of the angle between the two pulsars. Additional polarization modes (vector/scalar) that may arise in alternative-gravity theories have different angular correlation functions. Furthermore, anisotropy, linear, or circular polarization in the stochastic GW background gives rise to additional structure in the two-point correlation function that cannot be written simply in terms of the angular separation of the two pulsars. In this paper, we provide a simple formula for the most general two-point correlation function--or overlap reduction function (ORF)--for a gravitational-wave background with an arbitrary polarization state, possibly containing anisotropies in its intensity and polarization (linear or circular). We provide specific expressions for the ORFs sourced by the general-relativistic transverse-traceless GW modes as well as vector (or spin-1) modes that may arise in alternative-gravity theories.
format Preprint
id arxiv_https___arxiv_org_abs_2311_14159
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Efficient Computation of Overlap Reduction Functions for Pulsar Timing Arrays
Kumar, Neha Anil
Kamionkowski, Marc
Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
High Energy Physics - Phenomenology
Pulsar timing arrays seek and study gravitational waves (GWs) through the angular two-point correlation function of timing residuals they induce in pulsars. The two-point correlation function induced by the standard transverse-traceless GWs is the famous Hellings-Downs curve, a function only of the angle between the two pulsars. Additional polarization modes (vector/scalar) that may arise in alternative-gravity theories have different angular correlation functions. Furthermore, anisotropy, linear, or circular polarization in the stochastic GW background gives rise to additional structure in the two-point correlation function that cannot be written simply in terms of the angular separation of the two pulsars. In this paper, we provide a simple formula for the most general two-point correlation function--or overlap reduction function (ORF)--for a gravitational-wave background with an arbitrary polarization state, possibly containing anisotropies in its intensity and polarization (linear or circular). We provide specific expressions for the ORFs sourced by the general-relativistic transverse-traceless GW modes as well as vector (or spin-1) modes that may arise in alternative-gravity theories.
title Efficient Computation of Overlap Reduction Functions for Pulsar Timing Arrays
topic Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
High Energy Physics - Phenomenology
url https://arxiv.org/abs/2311.14159