Unifying cluster and galaxy cosmology analyses using the galaxy-halo connection

TL;DR

This paper introduces a unified, simulation-based framework that models galaxies and clusters together via the galaxy-halo connection, enhancing cosmological parameter constraints by combining multiple probes.

Contribution

It presents a novel integrated approach to analyze galaxy and cluster data simultaneously, improving cosmological constraints and enabling detailed tests of models.

Findings

Combining galaxy and cluster data improves the $\sigma_8-\Omega_m$ figure of merit by a factor of 15.

The framework is validated on the FLAMINGO simulation.

It enables the use of small-scale information for cosmological tests.

Abstract

Galaxies and galaxy clusters trace the same cosmic density field, but their statistics have been modeled separately in cosmological analyses. We present a unified, simulation-based framework to model them using the galaxy-halo connection. Our analysis includes cluster lensing, galaxy clustering, and galaxy-cluster cross-correlation. We validate our method on the FLAMINGO hydrodynamic simulation. Relative to the cluster-only approach, combining these probes improves the $\sigma_8-\Omega_m$ figure of merit by a factor of 15. Our framework enables stringent tests of cosmological models and exploits small-scale information.