On the Prospects of Measuring the Cosmic Dawn 21-cm Power Spectrum using the Upgraded Giant Meterwave Radio Telescope (uGMRT)

Abstract

A recent observation by the Experiment to Detect the Global Epoch of Reionization Signature collaboration shows a strong absorption signal in the global 21-cm spectrum from around a redshift of z = 17. This absorption is stronger than the maximum prediction by existing models and indicates that the spatial fluctuations of the H I 21-cm brightness temperature at cosmic dawn could be an order of magnitude larger than previously expected. In this paper, we investigate the prospects of detecting the H I 21-cm power spectrum from cosmic dawn using uGMRT. We find that a 10σ detection of the enhanced H I 21-cm signal power spectrum is possible within 70, 140, and 400 h of observation for an optimistic, moderate, and pessimistic scenario, respectively, using the Band-1 of uGMRT. This could be a useful probe of the interaction between the baryon and dark matter particles in the early Universe. We also present a comparison of the uGMRT predictions with those for the future SKA-Low.