Excursion set theory for modified gravity: correlated steps, mass functions and halo bias

TL;DR

This paper investigates how correlated steps affect the halo mass function, bias, and environmental dependencies in modified gravity models, especially chameleon models, using the excursion set theory.

Contribution

It introduces correlated steps into the excursion set framework for modified gravity, revealing significant impacts on mass functions and halo bias, and suggests environmental measurements can constrain these models.

Findings

Correlated steps significantly modify the halo mass function.

Environmental measurements can strongly constrain chameleon models.

Enhancement of fifth force effects in the conditional mass function and bias.

Abstract

We show how correlated steps introduces significant contributions to the modification of the halo mass function in modified gravity models, taking the chameleon models as an example, in the framework of the excursion set approach. This correction applies to both Lagrangian and Eulerian environments discussed in previous studies. Correlated steps also enhances the modifications due to the fifth force in the conditional mass function as well as the halo bias. We found that abundance and clustering measurements from different environments can provide strong constraints on the chameleon models.