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Scalar-induced gravitational wave interpretation of PTA data: the role of scalar fluctuation propagation speed

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arxiv 2307.08552 v1 pith:YULDKJX2 submitted 2023-07-17 gr-qc astro-ph.CO

Scalar-induced gravitational wave interpretation of PTA data: the role of scalar fluctuation propagation speed

classification gr-qc astro-ph.CO
keywords gravitationalwavebackgroundprimordialblackfluctuationspropagationscalar
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved
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Pulsar timing arrays gathered evidence of the presence of a gravitational wave background around nHz frequencies. If the gravitational wave background was induced by large and Gaussian primordial fluctuations, they would then produce too many sub-solar mass primordial black holes. We show that if at the time of gravitational wave generation the universe was dominated by a canonical scalar field, with the same equation of state as standard radiation but a higher propagation speed of fluctuations, one can explain the gravitational wave background with a primordial black hole counterpart consistent with observations. Lastly, we discuss possible ways to test this model with future gravitational wave detectors.

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Cited by 11 Pith papers

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