Inflationary interpretation of the stochastic gravitational wave background signal detected by pulsar timing array experiments
University of Trento · Istituto Nazionale di Fisica Nucleare, Trento Institute for Fundamental Physics And Applications
Abstract
Various pulsar timing array (PTA) experiments (NANOGrav, EPTA, PPTA, CPTA, including data from InPTA) very recently reported evidence for excess red common-spectrum signals in their latest datasets, with inter-pulsar correlations following the Hellings-Downs pattern, pointing to a stochastic gravitational wave background (SGWB) origin. Focusing for concreteness on the NANOGrav signal (given that all signals are in good agreement between each other), I inspect whether it supports an inflationary SGWB explanation, finding that such an interpretation calls for an extremely blue tensor spectrum, with spectral index nT≃1.8±0.3, while Big Bang Nucleosynthesis limits require a very low reheating scale, Trh≲10GeV.…
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Authors
1Topics & keywords
- Pulsar
- Gravitational wave
- Physics
- Gravitational wave background
- Interpretation (philosophy)
- Astrophysics
- SIGNAL (programming language)
- Astronomy