Constraining primordial non-Gaussianity by combining next-generation galaxy and 21 cm intensity mapping surveys
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Date
2023
Journal Title
Journal ISSN
Volume Title
Publisher
Institute for Ionics
Abstract
Surveys of the matter distribution contain ‘fossil’ information on possible non-Gaussianity that is generated in
the primordial universe. This primordial signal survives only on the largest scales where cosmic variance is strongest. By
combining different surveys in a multi-tracer approach, we can suppress the cosmic variance and significantly improve
the precision on the level of primordial non-Gaussianity.We consider a combination of an optical galaxy survey, like the
recently initiated DESI survey, together with a new and very different type of survey, a 21cm intensity mapping survey,
like the upcoming SKAO survey. A Fisher forecast of the precision on the local primordial non-Gaussianity parameter
fNL, shows that this multi-tracer combination, together with non-overlap single-tracer information, can deliver precision
comparable to that from the CMB. Taking account of the largest systematic, i.e. foreground contamination in intensity
mapping, we find that σ( fNL) ∼ 4
Description
Keywords
Cosmic variance, Primordial Universe, Optical galaxy survey, Primordial non-Gaussianity parameter
Citation
Jolicoeur, S., Maartens, R., & Dlamini, S. (2023). Constraining primordial non-gaussianity by combining next-generation galaxy and 21 cm intensity mapping surveys. European Physical Journal C, 83(4) doi:10.1140/epjc/s10052-023-11482-2