The nanohertz stochastic gravitational wave background from cosmic string loops and the abundant high redshift massive galaxies

• DOI: 10.1007/s11433-023-2262-0
• Publication Date: 2023-11-24T15:02:10Z
• Authors: Ziwei Wang; Lei Lei; Hao Jiao; Lei Feng; Yi-Zhong Fan
• Keywords: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology; Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph); FOS: Physical sciences; General Relativity and Quantum Cosmology (gr-qc); Astrophysics - High Energy Astrophysical Phenomena; General Relativity and Quantum Cosmology; Astrophysics - Cosmology and Nongalactic Astrophysics

Recently, pulsar timing array (PTA) experiments have provided compelling evidence for the existence of the nanohertz stochastic gravitational wave background (SGWB). In this work, we demonstrated that cosmic string loops generated from cosmic global strings offer a viable explanation for the observed nanohertz SGWB data, requiring a cosmic string tension parameter of $\log(Gμ) \sim -12$ and a loop number density of $\log N \sim 4$. Additionally, we revisited the impact of cosmic string loops on the abundance of massive galaxies at high redshifts. However, our analysis revealed challenges in identifying a consistent parameter space that can concurrently explain both the SGWB data and observations from the James Webb Space Telescope. This indicates the necessity for either extending the existing model employed in this research or acknowledging distinct physical origins for these two phenomena.<br/>7 pages, 4 figures, accepted for publication in Sci. China-Phys. Mech. Astron. (SCPMA)<br/>