Detecting the relativistic bispectrum in 21cm intensity maps. Issue 6 (22nd June 2021)

• Record Type: Journal Article
• Authors: Jolicoeur, Sheean; Maartens, Roy; De Weerd, Eline M.; Umeh, Obinna; Clarkson, Chris; Camera, Stefano
• Is Part Of: Journal of cosmology and astroparticle physics. Volume 2021:Issue 6(2021)
• Publication Date: 2021-06-22
• Subjects: power spectrum -- redshift surveys -- cosmological parameters from LSS; Cosmology -- Periodicals; Astrophysics -- Periodicals; 523.0105
• DOI: 10.1088/1475-7516/2021/06/039
• Languages: English
• ISSNs: 1475-7516

Abstract

Abstract: We investigate the detectability of leading-order relativistic effects in the bispectrum of future 21cm intensity mapping surveys. The relativistic signal arises from Doppler and other line-of-sight effects in redshift space. In the power spectrum of a single tracer, these effects are suppressed by a factor ℋ 2 /k 2 . By contrast, in the bispectrum the relativistic signal couples to short-scale modes, leading to an imaginary contribution that scales as ℋ/k, thus increasing the possibility of detection. Previous work has shown that this relativistic signal is detectable in a Stage IV Hα galaxy survey. We show that the signal is also detectable by next-generation 21cm intensity maps, but typically with a lower signal-to-noise, due to foreground and telescope beam effects.