A test of gravity with Pulsar Timing Arrays

A successful measurement of the Stochastic Gravitational Wave Background (SGWB) in Pulsar Timing Arrays (PTAs) would open up a new window through which to test the predictions of General Relativity (GR). We consider how these measurements might reveal deviations from GR by studying the overlap reduc...

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Bibliographic Details
Published in:Journal of cosmology and astroparticle physics 2023-11, Vol.2023 (11), p.42
Main Authors: Liang, Qiuyue, Lin, Meng-Xiang, Trodden, Mark
Format: Article
Language:English
Subjects:
Angular distribution
Arrays
Gravitational waves
gravitational waves / theory
Gravitational waves in GR and beyond: theory
Parameter modification
particle physics - cosmology connection
Phase velocity
Pulsars
Relativity
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Summary:A successful measurement of the Stochastic Gravitational Wave Background (SGWB) in Pulsar Timing Arrays (PTAs) would open up a new window through which to test the predictions of General Relativity (GR). We consider how these measurements might reveal deviations from GR by studying the overlap reduction function — the quantity that in GR is approximated by the Hellings-Downs curve — in some sample modifications of gravity, focusing on the generic prediction of a modified dispersion relation for gravitational waves. We find a distinct signature of such modifications to GR — a shift in the minimum angle of the angular distribution — and demonstrate that this shift is quantitatively sensitive to any change in the phase velocity. In a given modification of gravity, this result can be used, in some regions of parameter space, to distinguish the effect of a modified dispersion relation from that due to the presence of extra polarization modes.
ISSN:1475-7516
1475-7516
DOI:10.1088/1475-7516/2023/11/042