Mapping the galaxy-halo connection to the galaxy bias: implication to the HOD-informed prior

TL;DR

This paper examines how different halo occupation models influence galaxy bias priors, highlighting the importance of accounting for assembly bias to improve cosmological parameter constraints.

Contribution

It demonstrates the impact of assembly bias on quadratic galaxy bias parameters and emphasizes incorporating such effects for more accurate priors in cosmological studies.

Findings

Assembly bias significantly affects quadratic bias parameters.

Including halo concentration dependence alters bias priors.

Accounting for galaxy-halo connection models improves cosmological analysis robustness.

Abstract

The galaxy bias parameters are crucial for modeling the large-scale structure in cosmology, yet uncertainties in these parameters often degrade the precision of cosmological constraints. In this work, we investigate how different Halo Occupation Distribution (HOD) models impact the priors of the galaxy bias parameters, particularly focusing on quadratic bias parameters. We generate galaxy mock catalogs using various HOD models, including a standard model and one incorporating halo concentration dependence to account for assembly bias, and measure the galaxy bias parameters with high precision using the quadratic field method. We show that the inclusion of assembly bias associated to halo concentration could significantly impact the distributions of quadratic galaxy bias parameters, especially $b_2$. Our findings suggest that accounting for assembly bias or other galaxy-halo connection models is important for obtaining accurate priors on the galaxy bias parameters, thereby improving the robustness of cosmological analyses with galaxy clustering.