A Multi-messenger view of Cosmic Dawn: Conquering the Final Frontier

TL;DR

This paper reviews how multi-messenger observations of Cosmic Dawn can significantly enhance our understanding of the universe's early structure, baryonic matter distribution, and fundamental physics beyond the standard cosmological model.

Contribution

It introduces an innovative modeling approach linking baryonic gas observations to dark matter haloes, enabling better constraints on cosmology from future multi-messenger data.

Findings

Enhanced mapping of baryonic matter from Cosmic Dawn to today

Potential to test theories beyond the standard $\\Lambda$CDM model

Insights into properties of the first supermassive black holes

Abstract

The epoch of Cosmic Dawn, when the first stars and galaxies were born, is widely considered the final frontier of observational cosmology today. Mapping the period between Cosmic Dawn and the present-day provides access to more than 90% of the baryonic (normal) matter in the Universe, and unlocks several thousand times more Fourier modes of information than available in today's cosmological surveys. We review the progress in modelling baryonic gas observations as tracers of the cosmological large-scale structure from Cosmic Dawn to the present day. We illustrate how the description of dark matter haloes can be extended to describe baryonic gas abundances and clustering. This innovative approach allows us to fully utilize our current knowledge of astrophysics to constrain cosmological parameters from future observations. Combined with the information content of multi-messenger probes, this will also elucidate the properties of the first supermassive black holes at Cosmic Dawn. We present a host of fascinating implications for constraining physics beyond the $\Lambda$CDM model, including tests of the theories of inflation and the cosmological principle, the effects of non-standard dark matter, and possible deviations from Einstein's general relativity on the largest scales.