Journal
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Volume 499, Issue 4, Pages 5993-6008Publisher
OXFORD UNIV PRESS
DOI: 10.1093/mnras/staa3091
Keywords
cosmology: theory; (cosmology:) dark ages, reionization, first stars; (cosmology:) early Universe
Categories
Funding
- Royal Society University Research Fellowship
- ISF-NSFC joint research program [2580/17]
Ask authors/readers for more resources
Radio sources are expected to have formed at high redshifts, producing an excess radiation background above the cosmic microwave background (CMB) at low frequencies. Their effect on the redshifted 21-cm signal of neutral hydrogen is usually neglected, as it is assumed that the associated background is small. Recently, an excess radio background has been proposed as a possible explanation for the unusually strong 21-cm signal reported by EDGES. As a result, the implications of a smooth and extremely strong excess radio background on both the sky-averaged 21-cm signal and its fluctuations have been considered. Here, we take into account the inhomogeneity of the radio background created by a population of high-redshift galaxies and show that it adds a new type of 21-cm fluctuations to the well-known contributions of density, velocity, Ly alpha coupling, heating, and reionization. We find that a population of high-redshift galaxies even with a moderately enhanced radio efficiency (unrelated to the EDGES result) can have a significant effect on the 21-cm power spectrum and global signal. For models that can explain the EDGES data, we show that the 21-cm power spectrum at z similar to 17 is enhanced by up to two orders of magnitude compared to the CMB-only standard case, with a significantly modified shape and time evolution due to radio fluctuations. These fluctuations are within reach of upcoming radio interferometers. We also find that these models can be significantly constrained by current and future observations of radio sources.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available