Multimessenger cosmology: Correlating cosmic microwave background and stochastic gravitational wave background measurements

Peter Adshead, Niayesh Afshordi, Emanuela Dimastrogiovanni, Matteo Fasiello, Eugene A. Lim, Gianmassimo Tasinato

Research output: Contribution to journalArticlepeer-review

Abstract

Characterizing the physical properties of the stochastic gravitational wave background (SGWB) is a key step towards identifying the nature of its possible origin. We focus our analysis on SGWB anisotropies. The existence of a nontrivial primordial scalar-tensor-tensor (STT) correlation in the squeezed configuration may be inferred from the effect that a long wavelength scalar mode has on the gravitational wave power spectrum: an anisotropic contribution. Crucially, such a contribution is correlated with temperature anisotropies in the cosmic microwave background (CMB). We show that, for inflationary models that generate suitably large STT non-Gaussianities, cross correlating the CMB with the stochastic background of gravitational waves is a very effective probe of early universe physics. The resulting signal can be a smoking gun for primordial SGWB anisotropies.

Original languageEnglish (US)
Article number023532
JournalPhysical Review D
Volume103
Issue number2
DOIs
StatePublished - Jan 26 2021

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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