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2–13 juin 2025
Institut Pascal
Fuseau horaire Europe/Paris

Primordial non-Gaussianity - the effects of relativistic and wide-angle corrections to the power spectrum

12 juin 2025, 10:40
20m
Institut Pascal

Institut Pascal

Rue André Rivière 91400 Orsay France

Orateur

Sêcloka Lazare Guedezounme (University of the Western Cape)

Description

Wide-angle and relativistic corrections to the Newtonian and flat-sky approximations are important for accurate modelling of the galaxy power spectrum of next-generation galaxy surveys. In addition to Doppler and Sachs-Wolfe relativistic corrections, we include the effects of lensing convergence, time delay and integrated Sachs-Wolfe. We investigate the impact of these corrections on measurements of the local primordial non-Gaussianity parameter fNL, using two futuristic spectroscopic galaxy surveys, planned for SKAO2 and MegaMapper. In addition to the monopole, we include the quadrupole of the galaxy Fourier power spectrum. The quadrupole is much more sensitive to the corrections than the monopole. The combination with the quadrupole improves the precision on fNL by 40% and 60% for SKAO2 and MegaMapper respectively. Neglecting the wide-angle and relativistic corrections produces a shift in fNL of 0.1σ and 0.2σ for SKAO2 and MegaMapper. The shift in fNL is very sensitive to the magnification bias and the redshift evolution of the comoving number density. For these surveys, the contributions to the shift from integrated and non-integrated effects partly cancel. We point out that some of the approximations made in the corrections may artificially suppress the shift in fNL.

Documents de présentation

Aucun document.