Constraining primordial non-gaussianity by combining next-generation galaxy and 21 cm intensity mapping surveys
Abstract
Surveys of the matter distribution contain ‘fossil’
information on possible non-Gaussianity that is generated in
the primordialUniverse. 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.