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

TL;DR

Future 21cm intensity mapping surveys, especially in interferometer mode, can effectively constrain primordial non-Gaussianity by analyzing the combined power spectrum and bispectrum signals, with different modes excelling in different measurements.

Contribution

This study compares the effectiveness of single-dish and interferometer mode surveys in constraining primordial non-Gaussianity using 21cm intensity mapping, highlighting mode-specific advantages.

Findings

Single-dish surveys outperform interferometers in power spectrum measurements.

Interferometer mode surveys are more effective for bispectrum constraints.

Combined analysis enhances the potential to probe primordial non-Gaussianity.

Abstract

After reionisation, the 21cm 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, \rev{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.