Constraining galaxy-halo connection with high-order statistics

TL;DR

This paper demonstrates that three-point galaxy clustering statistics can significantly improve constraints on galaxy-halo connection parameters, especially for luminous red galaxies, by analyzing mock data from the DESI survey.

Contribution

It introduces a method to use three-point statistics for constraining galaxy-halo models, showing improved precision over two-point functions for certain galaxy samples.

Findings

Three-point function constrains LRG halo mass with 0.46% precision.

Two-point function constrains LRG halo mass with 1.55% precision.

Measurement of three-point functions is computationally optimized using tabulation.

Abstract

We investigate using three-point statistics in constraining the galaxy-halo connection. We show that for some galaxy samples, the constraints on the halo occupation distribution parameters are dominated by the three-point function signal (over its two-point counterpart). We demonstrate this on mock catalogs corresponding to the Luminous Red Galaxies (LRGs), Emission-Line Galaxies (ELG), and quasars (QSOs) targeted by the Dark Energy Spectroscopic Instrument (DESI) Survey. The projected three-point function for triangle sides less up to 20$h^{-1}$ Mpc measured from a cubic Gpc of data can constrain the characteristic minimum mass of the LRGs with a precision of $0.46$ %. For comparison, similar constraints from the projected two-point function are $1.55$ %. The improvements for the ELGs and QSOs targets are more modest. In the case of the QSOs it is caused by the high shot-noise of the sample, and in the case of the ELGs, this is caused by the range of halo masses of the host halos. The most time-consuming part of our pipeline is the measurement of the three-point functions. We adopt a tabulation method, proposed in earlier works for the two-point function, to reduce significantly the required compute time for the three-point analysis.