Constraining the origin of the nanohertz gravitational-wave background by pulsar timing array observations of both the background and individual supermassive binary black holes

Fuente: arXiv
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Main Authors: Chen, Yunfeng, Yu, Qingjuan, Lu, Youjun
Format: Preprint
Published: 2024
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author Chen, Yunfeng
Yu, Qingjuan
Lu, Youjun
author_facet Chen, Yunfeng
Yu, Qingjuan
Lu, Youjun
contents The gravitational waves (GWs) from supermassive binary black holes (BBHs) are long sought by pulsar timing array experiments (PTAs), in the forms of both a stochastic GW background (GWB) and individual sources. The evidence for a GWB was reported recently by several PTAs with origins to be determined. Here we use a BBH population synthesis model to investigate the detection probability of individual BBHs by the Chinese PTA (CPTA) and the constraint on the GWB origin that may be obtained by PTA observations of both GWB and individual BBHs. If the detected GWB signal is entirely due to BBHs, a significantly positive redshift evolution ($\propto(1+z)^{2.07}$) of the mass scaling relation between supermassive black holes and their host galaxies is required. In this case, we find that the detection probability of individual BBHs is $\sim85\%$ or 64% if using a period of 3.4-year CPTA observation data, with an expectation of $\sim1.9$ or 1.0 BBHs detectable with a signal-to-noise ratio $\geq3$ or $5$, and it is expected to increase to $>95\%$ if extending the observation period to $5$ years or longer. Even if the contribution from BBHs to the GWB power signal is as small as $\sim10\%$, a positive detection of individual BBHs can still be expected within an observation period of $\sim10$ years. A non-detection of individual BBHs within several years from now jointly with the detected GWB signal can put a strong constraint on the upper limit of the BBH contribution to the GWB signal and help identify/falsify a cosmological origin.
format Preprint
id arxiv_https___arxiv_org_abs_2409_18029
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Constraining the origin of the nanohertz gravitational-wave background by pulsar timing array observations of both the background and individual supermassive binary black holes
Chen, Yunfeng
Yu, Qingjuan
Lu, Youjun
High Energy Astrophysical Phenomena
Astrophysics of Galaxies
General Relativity and Quantum Cosmology
The gravitational waves (GWs) from supermassive binary black holes (BBHs) are long sought by pulsar timing array experiments (PTAs), in the forms of both a stochastic GW background (GWB) and individual sources. The evidence for a GWB was reported recently by several PTAs with origins to be determined. Here we use a BBH population synthesis model to investigate the detection probability of individual BBHs by the Chinese PTA (CPTA) and the constraint on the GWB origin that may be obtained by PTA observations of both GWB and individual BBHs. If the detected GWB signal is entirely due to BBHs, a significantly positive redshift evolution ($\propto(1+z)^{2.07}$) of the mass scaling relation between supermassive black holes and their host galaxies is required. In this case, we find that the detection probability of individual BBHs is $\sim85\%$ or 64% if using a period of 3.4-year CPTA observation data, with an expectation of $\sim1.9$ or 1.0 BBHs detectable with a signal-to-noise ratio $\geq3$ or $5$, and it is expected to increase to $>95\%$ if extending the observation period to $5$ years or longer. Even if the contribution from BBHs to the GWB power signal is as small as $\sim10\%$, a positive detection of individual BBHs can still be expected within an observation period of $\sim10$ years. A non-detection of individual BBHs within several years from now jointly with the detected GWB signal can put a strong constraint on the upper limit of the BBH contribution to the GWB signal and help identify/falsify a cosmological origin.
title Constraining the origin of the nanohertz gravitational-wave background by pulsar timing array observations of both the background and individual supermassive binary black holes
topic High Energy Astrophysical Phenomena
Astrophysics of Galaxies
General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2409.18029