The cosmological ultra-low frequency radio background: A solution to the Hubble tension and the 21-cm excess trough

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Abstract

Recent observations of the Cosmic Microwave Background and the Hubble Space Telescope obtain two different values of the Hubble constant with a discrepancy of at least 4.4 σ , which is now known as the Hubble tension. On the other hand, observations of 21-cm signal from the EDGES experiment reveal an unexpected excess absorption trough. These results give a big challenge to the standard cosmological model – the Λ CDM model. In this article, we propose that the existence of a cosmological ultra-low frequency radio background (ULFRB) can simultaneously reconcile both discrepancies. The best-fit amounts of the energy density of this additional radio component based on the two problems give an excellent agreement with each other. The extra radio component could be arisen from the simulated decay of axions in the early universe. Copyright © 2023 The Author(s).

Original languageEnglish
Article number509
JournalEuropean Physical Journal C
Volume83
DOIs
Publication statusPublished - Jun 2023

Citation

Chan, M. H. (2023). The cosmological ultra-low frequency radio background: A solution to the Hubble tension and the 21-cm excess trough. The European Physical Journal C, 83, Article 509. https://doi.org/10.1140/epjc/s10052-023-11669-7

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