Concerns about Modelling of the EDGES Data
Abstract
It is predicted that the spectrum of radio emission from the whole sky should show a dip arising from the action of the light from the first stars on the hydrogen atoms in the surrounding gas, which causes the 21-cm line to appear in absorption against the cosmic microwave background. Bowman et al. 2018 identified a broad flat-bottomed absorption profile centred at 78 MHz, which could be this feature, although the depth of the profile is much larger than expected. We have examined the modelling process they used and find that their data implies unphysical parameters for the foreground emission and also that their solution is not unique in the sense that we found other simple formulations for the signal that are different in shape but that also fit their data. We argue that this calls into question the interpretation of these data as an unambiguous detection of the cosmological 21-cm absorption signature.
Cite
@article{arxiv.1805.01421,
title = {Concerns about Modelling of the EDGES Data},
author = {Richard Hills and Girish Kulkarni and P. Daniel Meerburg and Ewald Puchwein},
journal= {arXiv preprint arXiv:1805.01421},
year = {2020}
}
Comments
6 pages, 2 figures; Accepted version of article published December 19, 2018. Full edited version (incl. supplementary information) available through Springer Nature at https://doi.org/10.1038/s41586-018-0796-5