PREPRINT

Full forward model of galaxy clustering statistics with simulation lightcones

Sihan Yuan, Boryana Hadzhiyska, Tom Abel

Submitted on 3 November 2022

Abstract

Novel summary statistics beyond the standard 2-point correlation function (2PCF) are necessary to capture the full astrophysical and cosmological information from the small-scale ($r<30{h}^{-1}$Mpc) galaxy clustering. However, the analysis of beyond-2PCF statistics on small scales is challenging because we lack the appropriate treatment of observational systematics for arbitrary summary statistics of the galaxy field. In this paper, we develop a full forward modeling pipeline for any summary statistics using high-fidelity simulation lightcones that accounts for all observational systematics and is appropriate for a wide range of summary statistics. We apply our forward model approach to a fully realistic mock galaxy catalog and demonstrate that we can recover unbiased constraints on the underlying galaxy--halo connection model using two separate summary statistics: the standard 2PCF and the novel $k$-th nearest neighbor ($k$NN) statistics, which are sensitive to correlation functions of all orders. We expect that applying this forward model approach to current and upcoming surveys while leveraging a multitude of summary statistics will become a powerful technique in maximally extracting information from the non-linear scales.