3D Galaxy Clustering with Future Wide-Field Surveys: Advantages of a Spherical Fourier-Bessel analysis

Context. Upcoming spectroscopic galaxy surveys are extremely promising for addressing the current challenges of cosmology, in particular to understand the nature of the dark universe. The strength of these surveys, best described in spherical geometry, comes from their unprecedented depth and width but optimal extraction of the three-dimensional information they contain is of utmost importance in order to best constrain the properties of dark energy. Aims. Though there is theoretical motivation and novel tools to explore these surveys using the 3D spherical Fourier-Bessel (SFB) power spectrum of galaxy number counts C`(k, k ′), most survey optimisations and forecasts are based on the tomographic spherical harmonics power spectrum C (ij) `. The goal of this paper is to perform a new investigation of the information that can be extracted from both analysis, in the context of planned stage IV wide-field galaxy surveys. Methods. We compare both tomographic and 3D SFB techniques in terms of forecasted cosmological parameters constraints by performing a Fisher analysis. The comparison is made possible by careful and coherent exclusion of non-linear scales from both analysis. We include for the first time nuisance parameters related to a scale and redshif