Joint analysis of anisotropic power spectrum, bispectrum and trispectrum: application to N-body simulations

TL;DR

This paper performs a pioneering joint analysis of power spectrum, bispectrum, and trispectrum in redshift space from N-body simulations, significantly tightening constraints on cosmological parameters for upcoming galaxy surveys.

Contribution

It introduces the first combined analysis of anisotropic power spectrum, bispectrum, and trispectrum, demonstrating their complementary power in constraining cosmology.

Findings

Constraints on parameters are significantly improved, with credible regions reduced by up to 78%.

Joint analysis enhances the precision of cosmological parameter estimation.

Results highlight the importance of including higher-order statistics in future surveys.

Abstract

We perform for the first time a joint analysis of the monopole and quadrupoles for power spectrum, bispectrum and integrated trispectrum (i-trispectrum) from the redshift space matter field in N-body simulations. With a full Markov Chain Monte Carlo exploration of the posterior distribution, we quantify the constraints on cosmological parameters for an object density of $n_\mathrm{p}=5\times10^{-4} (h\,\mathrm{Mpc}^{-1})^{3}$, redshift $z=0.5$, and a covariance corresponding to a survey volume of $V_\mathrm{survey} =25\,(h^{-1}\mathrm{Gpc})^3$, a set up which is representative of forthcoming galaxy redshift surveys. We demonstrate the complementarity of the bispectrum and i-trispectrum in constraining key cosmological parameters. In particular, compared to the state-of-the-art power spectrum (monopole plus quadrupole) and bispectrum (monopole) analyses, we find 1D $68\%$ credible regions smaller by a factor of $(72\%,78\%,72\%,47\%,46\%)$ for the parameters $(f,\sigma_8,f_\mathrm{nl},\alpha_\parallel,\alpha_\perp)$ respectively. This work motivates the additional effort necessary to include the redshift-space anisotropic signal of higher-order statistics in the analysis and interpretation of ongoing and future galaxy surveys.