Full-sky bispectrum in redshift space for 21cm intensity maps
Ruth Durrer, Mona Jalilvand, Rahul Kothari, Roy Maartens, Francesco Montanari
Abstract
We compute the tree-level bispectrum of 21cm intensity mapping after reionisation. We work in directly observable angular and redshift space, focusing on equal-redshift \ncorrelations and thin redshift bins, for which the lensing contribution is negligible. We demonstrate the importance of the contributions from redshift-space distortions which typically dominate the result. Taking into account the effects of telescope beams and foreground cleaning, \nwe estimate the signal to noise, and show that the bispectrum is detectable by both SKA \nin single-dish mode and HIRAX in interferometer mode, especially at the lower redshifts in \ntheir respective ranges.