Spherical accretion of collisional gas in modified gravity I: self-similar solutions and a new cosmological hydrodynamical code

Abstract

The spherical collapse scenario has great importance in cosmology since it captures several crucial aspects of structure formation. The presence of self-similar solutions in the Einstein-de Sitter (EdS) model greatly simplifies its analysis, making it a powerful tool to gain valuable insights into the real and more complicated physical processes involved in galaxy formation. While there has been a large body of research to incorporate various additional physical processes into spherical collapse, the effect of modified gravity (MG) models, which are popular alternatives to the $\Lambda CDM$ paradigm to explain the cosmic acceleration, is still not well understood in this scenario. In this paper, we study the spherical accretion of collisional gas in a particular MG model, which is a rare case that also admits self-similar solutions. The model displays interesting behaviours caused by the enhanced gravity and a screening mechanism. Despite the strong effects of MG, we find that its self-similar solution agrees well with that of the EdS model. These results are used to assess a new cosmological hydrodynamical code for spherical collapse simulations introduced here, which is based on the hyperbolic partial differential equation engine ExaHyPE 2. Its good agreement with the theoretical predictions confirms the reliability of this code in modelling astrophysical processes in spherical collapse. We will use this code to study the evolution of gas in more realistic MG models in future work.

20 pages, 13 figures

References in corpus (12)

• The EAGLE project: Simulating the evolution and assembly of galaxies and their environments
• Einstein's Other Gravity and the Acceleration of the Universe
• Covariant Galileon
• A Survey of High Level Frameworks in Block-Structured Adaptive Mesh Refinement Packages
• Ghosts in the self-accelerating universe
• Constructing stabilized brane world models in five-dimensional Brans-Dicke theory
• Large-Scale Tests of the DGP Model
• Non-linear interactions in a cosmological background in the DGP braneworld
• Modelling Shock Heating in Cluster Mergers: I. Moving Beyond the Spherical Accretion Model
• Effects of shear and rotation on the spherical collapse model for clustering dark energy
• Spherical Collapse and Cluster Counts in Modified Gravity Models
• The splashback radius in symmetron gravity

Cited by in corpus (1)

• ExaGRyPE: Numerical General Relativity Solvers Based upon the Hyperbolic PDEs Solver Engine ExaHyPE