Effects of Linear Redshift Space Distortions and Perturbation Theory on BAOs: A 3D Spherical Analysis

TL;DR

This paper analyzes how linear redshift space distortions and perturbation theory affect BAO features in galaxy surveys using a spherical Fourier-Bessel formalism, highlighting the radialization of information and damping effects.

Contribution

It extends BAO analysis with spherical Fourier-Bessel expansion by incorporating non-linearities and redshift distortions, revealing the radialization of the power spectrum.

Findings

sFB power spectrum becomes purely radial in deep surveys

Redshift distortions do not prevent radialization of information

Non-linearities damp BAO oscillations in the power spectrum

Abstract

The Baryon Acoustic Oscillations (BAO) are features in the matter power spectrum on scales of order 100-150 h^{-1} Mpc that promise to be a powerful tool to constrain and test cosmological models. The BAO have attracted such attention that future upcoming surveys have been designed with the BAO at the forefront of the primary science goals. Recent studies have advocated the use of a spherical-Fourier Bessel (sFB) expansion for future wide field surveys that cover both wide and deep regions of the sky necessitating the simultaneous treatment of the spherical sky geometry as well as the extended radial coverage. Ignoring the possible effects of growth, which is not expected to be significant at low redshifts, we present an extended analysis of the BAOs using the sFB formalism by taking into account the role of non-linearities and linear redshift distortions in the oscillations observed in the galaxy power spectrum. The sFB power spectrum has both radial and tangential dependence and it has been shown that in the limit that we approach a deep survey the sFB power spectrum is purely radial and collapses to the Cartesian Fourier power spectrum. This radialisation of information is shown to hold even in the presence of redshift space distortions (RSD) and 1-loop corrections to the galaxy power spectrum albeit with modified tangential and radial dependence. As per previous studies we find that the introduction of non-linearities leads to a damping of the oscillations in the matter power spectrum.