Cunnington, StevenWatkinson, CatherinePourtsidou, Alkistis2021-10-212021-10-212021-07-30Cunnington. (2021). The H i intensity mapping bispectrum including observational effects. Monthly Notices of the Royal Astronomical Society., 507(2), 1623–1639. https://doi.org/10.1093/mnras/stab2200https://doi.org/10.1093/mnras/stab2200http://hdl.handle.net/10566/6933The bispectrum is a three-point statistic with the potential to provide additional information beyond power spectra analyses of survey data sets. Radio telescopes that broadly survey the 21-cm emission from neutral hydrogen (H I) are a promising way to probe LSS and in this work we present an investigation into the H I intensity mapping (IM) bispectrum using simulations. We present a model of the redshift space H I IM bispectrum including observational effects from the radio telescope beam and 21-cm foreground contamination. We validate our modelling prescriptions with measurements from robust IM simulations, inclusive of these observational effects. Our foreground simulations include polarization leakage, on which we use a principal component analysis cleaning method. We also investigate the effects from a non-Gaussian beam including side-lobes. For a MeerKAT-like single-dish IM survey at z = 0.39, we find that foreground removal causes an 8 per cent reduction in the equilateral bispectrum’s signal-to-noise ratio, whereas the beam reduces it by 62 per cent. We find our models perform well, generally providing χ2 dof ∼ 1, indicating a good fit to the data. Whilst our focus is on post-reionization, single-dish IM, our modelling of observational effects, especially foreground removal, can also be relevant to interferometers and reionization studies.endata analysis – methodsstatistical – cosmologyobservations – cosmologyMethodsArticle