Exact Modeling of Power Spectrum Multipole through Spherical Fourier-Bessel Basis

The three-dimensional galaxy power spectrum is a powerful probe of primordial non-Gaussianity and additional general relativistic effects, which become important on large scales. At the same time, wide-angle (WA) effects due to differing lines-of-sight (LOS) on the curved sky also become important w...

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Bibliographic Details
Published in:arXiv.org 2024-10
Main Authors: Wen, Robin Y, Grasshorn Gebhardt, Henry S, Chen, Heinrich, Doré, Olivier
Format: Article
Language:English
Subjects:
Couplings
Fourier-Bessel transformations
Line of sight
Multipoles
Relativistic effects
Online Access:Get full text
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Summary:The three-dimensional galaxy power spectrum is a powerful probe of primordial non-Gaussianity and additional general relativistic effects, which become important on large scales. At the same time, wide-angle (WA) effects due to differing lines-of-sight (LOS) on the curved sky also become important with large angular separation. In this work, we accurately model WA and Doppler effects using the spherical Fourier-Bessel (SFB) formalism, before transforming the result into the commonly used power spectrum multipoles (PSM). This mapping from the SFB power spectrum to PSM represents a new way to non-perturbatively model WA and GR effects present in the PSM, which we validate with log-normal mocks. Moreover, for the first time, we can compute the analytical PSM Gaussian covariance on large scales, exactly including WA-induced mode-couplings, without resorting to any plane-parallel approximations.
ISSN:2331-8422
DOI:10.48550/arxiv.2404.04812