On the relativistic mass function and averaging in cosmology

TL;DR

This paper proposes a relativistic approach to modeling cosmological structure formation, deriving a mass function for galaxy clusters using scalar averaging and a relativistic Zel'dovich approximation.

Contribution

It introduces a novel relativistic framework combining scalar averaging and RZA for structure formation and mass function estimation.

Findings

Provides a general relativistic prescription for galaxy cluster mass functions.

Utilizes an exact scalar averaging scheme with RZA as a closure condition.

Offers a new perspective on relativistic effects in cosmological structure formation.

Abstract

The general relativistic description of cosmological structure formation is an important challenge from both the theoretical and the numerical point of views. In this paper we present a brief prescription for a general relativistic treatment of structure formation and a resulting mass function on galaxy cluster scales in a highly generic scenario. To obtain this we use an exact scalar averaging scheme together with the relativistic generalization of Zel'dovich's approximation (RZA) that serves as a closure condition for the averaged equations.