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

¹ Paris Centre for Cosmological Physics, APC, AstroParticule et Cosmologie, Université Paris Diderot, CNRS/IN2P3, CEA/lrfu, Observatoire de Paris, Sorbonne Paris Cité, 10 rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13, France
e-mail: ivan.debono@apc.univ-paris7.fr
² Physics Department and Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA
e-mail: gfsmoot@lbl.gov
³ Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong

Received: 19 June 2015
Accepted: 14 September 2016

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.