Probing primordial non-Gaussianity with the power spectrum and bispectrum of future 21 cm intensity maps

After reionisation, the 21 cm emission line of neutral hydrogen within galaxies provides a tracer of dark matter. Next-generation intensity mapping surveys, with the SKA and other radio telescopes, will cover large sky areas and a wide range of redshifts, facilitating their use as probes of primordial non-Gaussianity. Previous works have shown that the bispectrum can achieve tight constraints on primordial non-Gaussianity with future surveys that are purposely designed for intensity mapping in interferometer mode. Here we investigate the constraints attainable from surveys operating in single-dish mode, using the combined power spectrum and bispectrum signal. In the case of the power spectrum, single-dish surveys typically outperform interferometer surveys. We find that the reverse holds for the bispectrum: single-dish surveys are not competitive with surveys designed for interferometer mode. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The 21 cm emission line of neutral hydrogen can trace dark matter after reionisation; Next-generation intensity mapping surveys may serve as probes of primordial non-Gaussianity; Single-dish surveys typically outperform interferometer surveys in power spectrum but are not competitive in bispectrum.