Cosmological Interpretation for the Stochastic Signal in Pulsar Timing Arrays

Fuente: arXiv
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Main Authors: Wu, Yu-Mei, Chen, Zu-Cheng, Huang, Qing-Guo
Format: Preprint
Published: 2023
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author Wu, Yu-Mei
Chen, Zu-Cheng
Huang, Qing-Guo
author_facet Wu, Yu-Mei
Chen, Zu-Cheng
Huang, Qing-Guo
contents The pulsar timing array (PTA) collaborations have recently reported compelling evidence for the presence of a stochastic signal consistent with a gravitational-wave background. In this letter, we combine the latest data sets from NANOGrav, PPTA and EPTA collaborations to explore the cosmological interpretations for the detected signal from first-order phase transitions, domain walls and cosmic strings, separately. We find that the first-order phase transitions and cosmic strings can give comparable interpretations compared to supermassive black hole binaries (SMBHBs) characterized by a power-law spectrum, but the domain wall model is strongly disfavored with the Bayes factor compared to the SMBHB model being 0.009. Furthermore, the constraints on the parameter spaces indicate that: 1) a strong phase transition at temperatures below the electroweak scale is favored and the bubble collisions make the dominant contribution to the energy density spectrum; 2) the cosmic string tension is $G μ\in [1.46, 15.3]\times 10^{-12}$ at $90\%$ confidence interval and a small reconnection probability $p<6.68\times 10^{-2}$ is preferred at $95\%$ confidence level, implying that the strings in (super)string theory are strongly favored over the classical field strings.
format Preprint
id arxiv_https___arxiv_org_abs_2307_03141
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Cosmological Interpretation for the Stochastic Signal in Pulsar Timing Arrays
Wu, Yu-Mei
Chen, Zu-Cheng
Huang, Qing-Guo
Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
High Energy Physics - Phenomenology
The pulsar timing array (PTA) collaborations have recently reported compelling evidence for the presence of a stochastic signal consistent with a gravitational-wave background. In this letter, we combine the latest data sets from NANOGrav, PPTA and EPTA collaborations to explore the cosmological interpretations for the detected signal from first-order phase transitions, domain walls and cosmic strings, separately. We find that the first-order phase transitions and cosmic strings can give comparable interpretations compared to supermassive black hole binaries (SMBHBs) characterized by a power-law spectrum, but the domain wall model is strongly disfavored with the Bayes factor compared to the SMBHB model being 0.009. Furthermore, the constraints on the parameter spaces indicate that: 1) a strong phase transition at temperatures below the electroweak scale is favored and the bubble collisions make the dominant contribution to the energy density spectrum; 2) the cosmic string tension is $G μ\in [1.46, 15.3]\times 10^{-12}$ at $90\%$ confidence interval and a small reconnection probability $p<6.68\times 10^{-2}$ is preferred at $95\%$ confidence level, implying that the strings in (super)string theory are strongly favored over the classical field strings.
title Cosmological Interpretation for the Stochastic Signal in Pulsar Timing Arrays
topic Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
High Energy Physics - Phenomenology
url https://arxiv.org/abs/2307.03141