Detecting the First Stars with REACH and Bayesian Statistics

The development of the universe between the emission of the CMB at the epoch of recombination and the emergence of modern structure is currently quite poorly understood. One of the most promising mechanisms for probing this period is the absorption of radiation at 21cm by neutral hydrogen, as the magnitude of absorption is affected by the properties of the surrounding gas and radiation field. As a result, the development of these properties can be traced if this absorption signal can be measured.
 
In this talk, I will give an overview of the current state of 21-cm cosmology and introduce the Radio Experiment for the Analysis of Cosmic Hydrogen (REACH). I will also discuss of the challenges involved in detecting the 21-cm signal, particularly the presence of bright radio foregrounds that can overwhelm the signal and systematic distortions arising from the antenna, and my work on overcoming these as part of REACH, using Bayesian statistical techniques.