21 cm intensity mapping with the Five hundred metre Aperture Spherical Telescope

TL;DR

This paper proposes using the FAST telescope to create large-scale 21 cm intensity maps of the sky, aiming to study cosmic structures and features from inflation, complementing galaxy surveys and future SKA observations.

Contribution

It introduces a novel survey method with FAST for large-scale 21 cm intensity mapping, enabling early insights into cosmic structures before SKA.

Findings

Potential to map large-scale structures up to redshift 2.5

Sensitivity to very large-scale features from inflation

Complementary data to galaxy surveys and CMB observations

Abstract

This paper describes a programme to map large-scale cosmic structures on the largest possible scales by using the Five hundred metre Aperture Spherical Telescope (FAST) to make a 21 cm (red-shifted) intensity map of the sky for the range $0.5 < z < 2.5$. The goal is to map to the angular and spectral resolution of FAST a large swath of the sky by simple drift scans with a transverse set of beams. This approach would be complementary to galaxy surveys and could be completed before the Square Kilometre Array (SKA) could begin a more detailed and precise effort. The science would be to measure the large-scale structure on the size of the baryon acoustic oscillations and larger scale, and the results would be complementary to its contemporary observations and significant. The survey would be uniquely sensitive to the potential very large-scale features from inflation at the Grand Unified Theory (GUT) scale and complementary to observations of the cosmic microwave background.