Spherical collapse in DGP braneworld cosmology

TL;DR

This paper investigates the nonlinear evolution of matter density in DGP braneworld cosmology using spherical collapse models, and compares galaxy cluster counts with standard cosmology, highlighting differences due to modified gravity.

Contribution

It introduces a semi-analytic spherical collapse approach in DGP cosmology and analyzes galaxy cluster counts using Press-Schechter and Sheth-Tormen formalisms, revealing enhanced cluster numbers.

Findings

DGP model predicts more galaxy clusters than ΛCDM for same parameters.

Spherical collapse method effectively models nonlinear evolution in DGP cosmology.

Galaxy cluster counts vary significantly between DGP and standard models.

Abstract

The DGP (Dvali, Gabadaze and Porrati) braneworld cosmology gives an alternative to dark energy. In DGP cosmology the alleged cosmic acceleration is generated by the modification of gravity theory. Nonlinear evolution of matter density contrast in DGP braneworld cosmology is studied in the present work. The semi-analytic approach of spherical collapse of matter overdensity is adopted in the present context to study the nonliner evolution. Further, the number count of galaxy clusters along the redshift is studied for the DGP cosmology using Press-Schechter and Sheth-Tormen mass function formalisms. It is observed that for same values of cosmological parameters, the DGP model enhances the number of galaxy cluster compared to the standard $\Lambda$CDM scenario.