Prospects for precision cosmology with the 21 cm signal from the dark ages

Rajesh Mondal*, Rennan Barkana

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


The 21 cm signal from the dark ages provides a potential new probe of fundamental cosmology. While exotic physics could be discovered, here we quantify the expected benefits within the standard cosmology. A measurement of the global (sky-averaged) 21 cm signal to the precision of thermal noise from a 1,000 h integration would yield a measurement within 10% of a combination of cosmological parameters. A 10,000 h integration would improve this measurement to 3.2% and constrain the cosmic helium fraction to 9.9%. Precision cosmology with 21 cm fluctuations requires a collecting area of 10 km2 (corresponding to 400,000 stations), which, with a 1,000 h integration, would exceed the same global case by a factor of ~2. Enhancing the collecting area or integration time by an order of magnitude would yield a 0.5% parameter combination, a helium measurement five times better than Planck and a constraint on the neutrino mass as good as Planck. Our analysis sets a baseline for upcoming lunar and space-based dark-ages experiments.

Original languageEnglish
Pages (from-to)1025-1030
Number of pages6
JournalNature Astronomy
Issue number9
StatePublished - Sep 2023


FundersFunder number
Israel Academy of Sciences and Humanities & Council for Higher Education Excellence Fellowship Program for International Postdoctoral Researchers
Israel Science Foundation2359/20


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