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

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Hauptverfasser: Guedezounme, Sêcloka L., Jolicoeur, Sheean, Maartens, Roy
Format: Preprint
Veröffentlicht: 2024
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author Guedezounme, Sêcloka L.
Jolicoeur, Sheean
Maartens, Roy
author_facet Guedezounme, Sêcloka L.
Jolicoeur, Sheean
Maartens, Roy
contents Wide-angle and relativistic corrections to the Newtonian and flat-sky approximations are important for accurate modeling 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 $f_{\mathrm{NL}}$, 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 $f_{\mathrm{NL}}$ by $\sim {45}\%$ and $\sim {63}\%$ for SKAO2 and MegaMapper respectively. {Neglecting the wide-angle and relativistic corrections produces a shift in $f_{\mathrm{NL}}$ which is very sensitive to the magnification bias and the redshift evolution of the comoving number density. In the case of SKAO2, the shift in $f_{\mathrm{NL}}$ is negligible -- since the contributions to the shift from integrated and non-integrated effects nearly cancel. For MegaMapper, there is only partial cancellation of integrated and non-integrated effects and the shift is $\sim {0.6} \, σ$.} We point out that some of the approximations made in the wide-angle and relativistic corrections may artificially suppress the shift in $f_{\mathrm{NL}}$.
format Preprint
id arxiv_https___arxiv_org_abs_2412_06553
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Primordial non-Gaussianity -- the effects of relativistic and wide-angle corrections to the power spectrum
Guedezounme, Sêcloka L.
Jolicoeur, Sheean
Maartens, Roy
Cosmology and Nongalactic Astrophysics
Wide-angle and relativistic corrections to the Newtonian and flat-sky approximations are important for accurate modeling 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 $f_{\mathrm{NL}}$, 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 $f_{\mathrm{NL}}$ by $\sim {45}\%$ and $\sim {63}\%$ for SKAO2 and MegaMapper respectively. {Neglecting the wide-angle and relativistic corrections produces a shift in $f_{\mathrm{NL}}$ which is very sensitive to the magnification bias and the redshift evolution of the comoving number density. In the case of SKAO2, the shift in $f_{\mathrm{NL}}$ is negligible -- since the contributions to the shift from integrated and non-integrated effects nearly cancel. For MegaMapper, there is only partial cancellation of integrated and non-integrated effects and the shift is $\sim {0.6} \, σ$.} We point out that some of the approximations made in the wide-angle and relativistic corrections may artificially suppress the shift in $f_{\mathrm{NL}}$.
title Primordial non-Gaussianity -- the effects of relativistic and wide-angle corrections to the power spectrum
topic Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2412.06553