Structure Formation in Generalized Rastall Gravity

Abstract

Recently a modified version of Rastall theory of gravity has been introduced in which a varying coupling parameter could act as dark energy (DE) and thus, it can be held responsible for the current accelerated expansion of the Universe. Motivated by this modification, we study here the evolution of linear and non-linear perturbations in the matter content of the Universe, utilizing spherically symmetric top-hat collapse scenario. The exact solutions we obtain in linear regime show that as the Universe evolves, matter density perturbations grow and reach a maximum value at a certain redshift after which these perturbations start decreasing towards a finite positive value at the present time. Depending on model parameters, exact oscillatory solutions can be also found representing that matter perturbations could experience either overdense and underdense regions during the dynamical evolution of the Universe. Numerical solutions in non-linear regime show that the amplitude of perturbations grow much faster than the linear one and diverges at a critical redshift. However, the formation of collapsed structures is delayed as compared to $\Lambda${\rm CDM} model. It is found that the running mutual interaction between matter and geometry, encoded in the variable Rastall coupling parameter, could drastically affect the dynamics of matter perturbations and their growth rate during the evolution of the Universe.

arXiv comment8 pages and 5 figures

References in corpus (39)

• Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant
• Measurements of Omega and Lambda from 42 High-Redshift Supernovae
• Dynamics of dark energy
• f(R) Theories Of Gravity
• Modified Gravity and Cosmology
• f(R) theories
• Cosmological Constant - the Weight of the Vacuum
• Imperfect Dark Energy from Kinetic Gravity Braiding
• Approaches to Understanding Cosmic Acceleration
• Covariant conservation of energy momentum in modified gravities
• On the spherical collapse model in dark energy cosmologies
• Non-linear Evolution of f(R) Cosmologies III: Halo Statistics
• The Imperfect Fluid behind Kinetic Gravity Braiding
• Rastall Cosmology and the ΛCDM Model
• Neutron Stars in Rastall Gravity
• A Generalization to the Rastall Theory and Cosmic Eras
• Structure formation in the presence of dark energy perturbations
• Spherical collapse in quintessence models with zero speed of sound
• Note on the Evolution of the Gravitational Potential in Rastall Scalar Field Theories
• Decoupling gravitational sources by MGD approach in Rastall gravity
• Conservation laws in theories with universal gravity/matter coupling
• Spherical collapse and halo mass function in f(R) theories
• Spherical Collapse in f(R) Gravity
• Clarifying spherical collapse in coupled dark energy cosmologies
• The Brans-Dicke-Rastall theory
• Cosmological consequences in the framework of generalized Rastall theory of gravity
• Does Chaplygin gas have salvation?
• The spherical collapse model in time varying vacuum cosmologies
• Spherical Collapse in Chameleon Models
• Cosmological consequences of a built-in cosmological constant model
• Spherical collapse model with non-clustering dark energy
• Generalized Mattig's relation in Brans-Dicke-Rastall gravity
• Perturbative analysis of generalized Einstein's theories
• Clustering dark energy and halo abundances
• Modified GR and Helium Nucleosynthesis
• Calculation of the critical overdensity in the spherical-collapse approximation
• Cosmology models with Ω_M-dependent cosmological constant
• Nonlinear spherical perturbations in Quintessence Models of Dark Energy
• Spherical collapse and cluster number counts in dark energy models disformally coupled to dark matter

Cited by in corpus (14)

• Growth of Perturbations in Tsallis and Barrow Cosmology
• Cosmic dynamics and qualitative study of Rastall model with spatial curvature
• Slow-roll inflation and growth of perturbations in Kaniadakis modification of Friedmann cosmology
• Qualitative study of anisotropic Rastall cosmologies
• Implications of the Conformal Constraint on Sound Speed on the Radius of PSR J0952-0607 within Rastall Gravity
• Quadratic Rastall Gravity: from low-mass HESS J1731-347 to high-mass PSR J0952-0607 pulsars
• Structure formation in mimetic gravity
• Conformal Killing cosmology -- Geometry, dark sector, growth of structures, and big rip
• Evolution of Spherical Overdensities in Energy-Momentum-Squared Gravity
• Effects of Rastall parameter on perturbation of dark sectors of the Universe
• Wormhole solutions in generalized Rastall gravity
• Non-minimal coupling inspires the Dirac cosmological model
• Constraints on cosmological parameters and CMB first acoustic peak in conformal Killing gravity
• Structure formation in a non-canonical scalar field model of clustering dark energy