Cosmological Background Interpretation of Pulsar Timing Array Data

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Hauptverfasser: Figueroa, Daniel G., Pieroni, Mauro, Ricciardone, Angelo, Simakachorn, Peera
Format: Preprint
Veröffentlicht: 2023
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author Figueroa, Daniel G.
Pieroni, Mauro
Ricciardone, Angelo
Simakachorn, Peera
author_facet Figueroa, Daniel G.
Pieroni, Mauro
Ricciardone, Angelo
Simakachorn, Peera
contents We discuss the interpretation of the detected signal by Pulsar Timing Array (PTA) observations as a gravitational wave background (GWB) of cosmological origin. We combine NANOGrav 15-years and EPTA-DR2new data sets and confront them against backgrounds from supermassive black hole binaries (SMBHBs), and cosmological signals from inflation, cosmic (super)strings, first-order phase transitions, Gaussian and non-Gaussian large scalar fluctuations, and audible axions. We find that scalar-induced, and to a lesser extent audible axion and cosmic superstring signals, provide a better fit than SMBHBs. These results depend, however, on modeling assumptions, so further data and analysis are needed to reach robust conclusions. Independently of the signal origin, the data strongly constrain the parameter space of cosmological signals, for example, setting an upper bound on primordial non-Gaussianity at PTA scales as $|f_{nl}| \lesssim 2.34$ at 95% CL.
format Preprint
id arxiv_https___arxiv_org_abs_2307_02399
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Cosmological Background Interpretation of Pulsar Timing Array Data
Figueroa, Daniel G.
Pieroni, Mauro
Ricciardone, Angelo
Simakachorn, Peera
Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
High Energy Physics - Phenomenology
We discuss the interpretation of the detected signal by Pulsar Timing Array (PTA) observations as a gravitational wave background (GWB) of cosmological origin. We combine NANOGrav 15-years and EPTA-DR2new data sets and confront them against backgrounds from supermassive black hole binaries (SMBHBs), and cosmological signals from inflation, cosmic (super)strings, first-order phase transitions, Gaussian and non-Gaussian large scalar fluctuations, and audible axions. We find that scalar-induced, and to a lesser extent audible axion and cosmic superstring signals, provide a better fit than SMBHBs. These results depend, however, on modeling assumptions, so further data and analysis are needed to reach robust conclusions. Independently of the signal origin, the data strongly constrain the parameter space of cosmological signals, for example, setting an upper bound on primordial non-Gaussianity at PTA scales as $|f_{nl}| \lesssim 2.34$ at 95% CL.
title Cosmological Background Interpretation of Pulsar Timing Array Data
topic Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
High Energy Physics - Phenomenology
url https://arxiv.org/abs/2307.02399