An MCMC approach to extracting the global 21-cm signal during the cosmic dawn from sky-averaged radio observations

TL;DR

This paper develops a Markov Chain Monte Carlo method to extract the cosmic dawn 21-cm signal from sky-averaged radio observations, accounting for foregrounds and instrumental effects, demonstrating its application to lunar orbit observations.

Contribution

It introduces a comprehensive model and MCMC approach for analyzing 21-cm signals, enabling better separation from foregrounds and instrumental effects in cosmic dawn studies.

Findings

Demonstrates the effectiveness of MCMC in separating 21-cm signals from foregrounds.

Shows the potential of the DARE mission for constraining properties of the first galaxies.

Provides a detailed observational model for lunar orbit radio measurements.

Abstract

Efforts are being made to observe the 21-cm signal from the 'cosmic dawn' using sky-averaged observations with individual radio dipoles. In this paper, we develop a model of the observations accounting for the 21-cm signal, foregrounds, and several major instrumental effects. Given this model, we apply Markov Chain Monte Carlo techniques to demonstrate the ability of these instruments to separate the 21-cm signal from foregrounds and quantify their ability to constrain properties of the first galaxies. For concreteness, we investigate observations between 40 and 120 MHz with the proposed DARE mission in lunar orbit, showing its potential for science return.