Full forward model of galaxy clustering statistics with simulation lightcones

Sihan Yuan, Boryana Hadzhiyska, Tom Abel

Submitted on 3 November 2022


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<30h1Mpc) 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 (kNN) 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.


Comment: comments welcome

Subject: Astrophysics - Cosmology and Nongalactic Astrophysics


The CMASS LRG footprint (indicated with blue points) compared to the trimmed footprint (enclosed by black lines). The lightcone footprint is rotated in RA to have maximally continuous overlap with the CMASS footprint. We apply a cut at DEC = 61$^\circ$ to remove regions of the lightcone that do not overlap with the CMASS footprint.