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Please use this identifier to cite or link to this item: http://hdl.handle.net/2289/8024
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dc.contributor.authorSingh, Saurabh-
dc.contributor.authorNambissan T., Jishnu-
dc.contributor.authorSubrahmanyan, Ravi-
dc.contributor.authorShankar, N. Udaya-
dc.contributor.authorGirish, B.S.-
dc.contributor.authorRaghunathan, A.-
dc.contributor.authorSomashekar, R.-
dc.contributor.authorSrivani, K.S.-
dc.contributor.authorMayuri Sathyanarayana, Rao-
dc.date.accessioned2023-01-19T08:56:46Z-
dc.date.available2023-01-19T08:56:46Z-
dc.date.issued2022-02-28-
dc.identifier.citationNature Astronomy, 2022, Vol.6, p607en_US
dc.identifier.issn2397-3366 (Online)-
dc.identifier.urihttp://hdl.handle.net/2289/8024-
dc.descriptionRestricted Access. An open-access version is available at arXiv.org (one of the alternative locations)en_US
dc.description.abstractThe astrophysics of the cosmic dawn, when star formation commenced in the first collapsed objects, is predicted to be revealed by spectral and spatial signatures in the cosmic radio background at long wavelengths. The sky-averaged redshifted 21 cm absorption line of neutral hydrogen is a probe of the cosmic dawn. The line profile is determined by the evolving thermal state of the gas, radiation background, Lyman α radiation from stars scattering off cold primordial gas, and relative populations of the hyperfine spin levels in neutral hydrogen atoms. We report a radiometer measurement of the spectrum of the radio sky in the 55–85 MHz band, which shows that the profile found by Bowman et al. in data taken with the Experiment to Detect the Global Epoch of Reionization Signature (EDGES) low-band instrument is not of astrophysical origin; their best-fitting profile is rejected with 95.3% confidence. The profile was interpreted to be a signature of the cosmic dawn; however, its amplitude was substantially higher than that predicted by standard cosmological models. Our non-detection bears out earlier concerns and suggests that the profile found by Bowman et al. is not evidence for new astrophysics or non-standard cosmology.en_US
dc.language.isoenen_US
dc.publisherNature Publishingen_US
dc.relation.urihttps://ui.adsabs.harvard.edu/abs/2022NatAs...6..607S/abstracten_US
dc.relation.urihttps://arxiv.org/abs/2112.06778en_US
dc.relation.urihttps://doi.org/10.1038/s41550-022-01610-5en_US
dc.rights2022 The Author(s)en_US
dc.titleOn the detection of a cosmic dawn signal in the radio backgrounden_US
dc.typeArticleen_US
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