Current status and future of cosmology with 21cm Intensity Mapping

TL;DR

This paper reviews the development, current status, and future prospects of 21cm Intensity Mapping for cosmology, highlighting its potential to map matter distribution and constrain cosmological models from the Epoch of Reionisation to late times.

Contribution

It provides a comprehensive overview of 21cm IM technology, recent experimental results, and discusses future large-scale surveys and their scientific goals.

Findings

Recent results from GBT, CHIME, and Tianlai demonstrate progress in 21cm IM.

Upcoming experiments like HIRAX, CHORD, and BINGO aim to improve cosmological constraints.

21cm IM shows promise for studying dark energy, inflation, and the matter distribution.

Abstract

21cm Intensity Mapping (IM) has been proposed about 15 years ago as a cost effective method to carry out cosmological surveys and to map the 3D distribution of matter in the universe, over a large range of post EoR redshifts, from z=0 to z=6. Since then a number of pathfinder instruments have been built, such as CHIME or Tianlai. Several other ones will be commissioned in the next few years (HIRAX, CHORD, BINGO), while even larger arrays, with several thousand antennae are being considered for the next generation experiments. We will briefly review the 21cm cosmology of the Epoch of Reionisation (EoR), and we will then focus on IM for late time cosmology. After presenting some of the promises of this technique to constrain the cosmological model, dark energy and inflation, we will review some of the instrumental and scientific challenges of IM surveys. The second part of the paper presents an overview of the ongoing and future experiments, as well as recent results by GBT, CHIME and Tianlai.