Observations of the 21-cm line from primordial hydrogen promise to be one of the best tools
to study the early epochs of the Universe: the dark ages, the cosmic dawn and the …

Cosmic dawn, the onset of star formation in the early universe, can in principle be studied
via the 21-cm transition of neutral hydrogen, for which a sky-averaged absorption signal …

Modeling the 21-cm global signal from the Cosmic Dawn is challenging due to the many
poorly constrained physical processes that come into play. We address this problem using …

The observation of the global 21 cm signal produced by neutral hydrogen gas in the
intergalactic medium (IGM) during the Dark Ages, Cosmic Dawn, and Epoch of Reionization …

The 21-cm signal from cosmic hydrogen is one of the most propitious probes of the early
Universe. The detection of this signal would reveal key information about the first stars, dark …

We present a Bayesian re-analysis of the sky-averaged 21-cm experimental data from
SARAS2 using nested sampling implemented with polychord, spectrally smooth foreground …

Considerable observational efforts are being dedicated to measuring the sky-averaged
(global) 21 cm signal of neutral hydrogen from Cosmic Dawn and the Epoch of Reionization …

The 21cm line refers to a forbidden transition in neutral hydrogen associated with alignment
of spins of the proton and electron. It is a very low energy transition that is emitted whenever …

Radio observations of the neutral hydrogen signal from the Cosmic Dawn and Epoch of
Reionization have helped to provide constraints on the properties of the first stars and …

We detail the REACH radiometric system designed to enable measurements of the 21-cm
neutral hydrogen line. Included is the radiometer architecture and end-to-end system …