Radio-optical synergies at high redshift to constrain primordial non-gaussianity

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dc.contributor.authorSquarotti, Matilde Barberi
dc.contributor.authorMaartens, Roy
dc.contributor.authorCamera, Stefano
dc.date.accessioned2025-01-22T08:00:27Z
dc.date.available2025-01-22T08:00:27Z
dc.date.issued2024
dc.description.abstractWe apply the multi-tracer technique to test the possibility of improved constraints on the amplitude of local primordial non-Gaussianity, fNL, in the cosmic large-scale structure. A precise measurement of fNL is difficult because the effects of non-Gaussianity mostly arise on the largest scales, which are heavily affected by the low statistical sampling commonly referred to as cosmic variance. The multi-tracer approach suppresses cosmic variance and we implement it by combining the information from next-generation galaxy surveys in the optical/near-infrared band and neutral hydrogen (Hi) intensity mapping surveys in the radio band. High-redshift surveys enhance the precision on fNL, due to the larger available volume, and Hi intensity mapping surveys can naturally reach high redshifts. In order to extend the redshift coverage of a galaxy survey, we consider different emission-line galaxy populations, focusing on the Hα line at low redshift and on oxygen lines at higher redshift. By doing so, we cover a wide redshift range 1 ≲ z ≲ 4. To assess the capability of our approach, we implement a synthetic-data analysis by means of Markov chain Monte Carlo sampling of the (cosmological+nuisance) parameter posterior, to evaluate the constraints on fNL obtained in different survey configurations. We find significant improvements from the multi-tracer technique: the full data set leads to a precision of σ(fNL) < 1.
dc.identifier.citationSquarotti, M.B., Camera, S. and Maartens, R., 2024. Radio-optical synergies at high redshift to constrain primordial non-Gaussianity. Journal of Cosmology and Astroparticle Physics, 2024(02), p.043.
dc.identifier.urihttps://doi.org/10.1088/1475-7516/2024/02/043
dc.identifier.urihttps://hdl.handle.net/10566/19902
dc.language.isoen
dc.publisherInstitute of Physics
dc.subjectCosmological parameters from LSS
dc.subjectNon-gaussianity
dc.subjectPower spectrum
dc.subjectRedshift surveys
dc.subjectRadio-optical synergies
dc.titleRadio-optical synergies at high redshift to constrain primordial non-gaussianity
dc.typeArticle

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