Spherical collapse and halo mass function in f(R) theories

Abstract

We compute the critical density of collapse for spherically symmetric overdensities in a class of f(R) modified gravity models. For the first time we evolve the Einstein, scalar field and non-linear fluid equations, making the minimal simplifying assumptions that the metric potentials and scalar field remain quasi-static throughout the collapse. Initially evolving a top hat profile, we find that the density threshold for collapse depends significantly on the initial conditions imposed, specifically the choice of size and shape. By imposing `natural' initial conditions, we obtain a fitting function for the spherical collapse delta_c as a function of collapse redshift, mass of the overdensity and f_{R0}, the background scalar field value at z=0. By extending delta_c into drifting and diffusing barrier within the context of excursion set theory, we obtain a realistic mass function that might be used to confront this class of scalar-tensor models with observations of dark matter halos. The proposed analytic formula for the halo mass function was tested against Monte Carlo random walks for a wide class of moving barriers and can therefore be applied to other modified gravity theories.

24 pages, 13 figures, corresponds to published version

References in corpus (14)

• Models of f(R) Cosmic Acceleration that Evade Solar-System Tests
• Disappearing cosmological constant in f(R) gravity
• Solar system and equivalence principle constraints on f(R) gravity by chameleon approach
• Degravitation of the Cosmological Constant and Graviton Width
• Non-linear Evolution of f(R) Cosmologies III: Halo Statistics
• Non-linear evolution of f(R) cosmologies II: power spectrum
• A new framework for analyzing the effects of small scale inhomogeneities in cosmology
• Cascading DGP
• Hamiltonian Formulation of Palatini f(R) theories a la Brans-Dicke
• Various Hamiltonian formulations of f(R) gravity and their canonical relationships
• Excursion Set Halo Mass Function and Bias in a Stochastic Barrier Model of Ellipsoidal Collapse
• Dynamically avoiding fine-tuning the cosmological constant: the "Relaxed Universe"
• Excursion Set Theory for generic moving barriers and non-Gaussian initial conditions
• LTB solutions in Newtonian gauge: from strong to weak fields

Cited by in corpus (58)

• Cosmology and Fundamental Physics with the Euclid Satellite
• The CosmoVerse White Paper: Addressing observational tensions in cosmology with systematics and fundamental physics
• Accurate halo-model matter power spectra with dark energy, massive neutrinos and modified gravitational forces
• Next Generation Cosmology: Constraints from the Euclid Galaxy Cluster Survey
• Fisher for complements: Extracting cosmology and neutrino mass from the counts-in-cells PDF
• Spherical collapse in Galileon gravity: fifth force solutions, halo mass function and halo bias
• The Novel Probes Project -- Tests of Gravity on Astrophysical Scales
• Constraining $f(R)$ Gravity Theory Using Weak Lensing Peak Statistics from the Canada-France-Hawaii-Telescope Lensing Survey
• Halo model and halo properties in Galileon gravity cosmologies
• The halo model for cosmology: a pedagogical review
• Halo modelling in chameleon theories
• Modelling Void Abundance in Modified Gravity
• Cluster abundance in chameleon $f(R)$ gravity I: toward an accurate halo mass function prediction
• Spherical collapse in f(R) gravity and the Belinskii-Khalatnikov-Lifshitz conjecture
• Joint halo mass function for modified gravity and massive neutrinos I: simulations and cosmological forecasts
• The Imprint of f(R) Gravity on Non-Linear Structure Formation
• Speeding up N-body simulations of modified gravity: Vainshtein screening models
• A parametrisation of modified gravity on nonlinear cosmological scales
• On the implementation of the spherical collapse model for dark energy models
• A general framework to test gravity using galaxy clusters I: Modelling the dynamical mass of haloes in $f(R)$ gravity
• Structure Formation in Generalized Rastall Gravity
• On the current status of Modified Gravity
• Observational constraints on Starobinsky $f(R)$ cosmology from cosmic expansion and structure growth data
• Turnaround radius in $f(R)$ model
• Nonlinear evolution of initially biased tracers in modified gravity
• Computation of the Halo Mass Function Using Physical Collapse Parameters: Application to Non-Standard Cosmologies
• A short review on clustering dark energy
• Constraining f(R) Gravity with Planck Sunyaev-Zel'dovich Clusters
• Relation between the Turnaround radius and virial mass in $f(R)$ model
• Cold dark energy constraints from the abundance of galaxy clusters
• The matter density PDF for modified gravity and dark energy with Large Deviations Theory
• Breaking cosmic degeneracies: Disentangling neutrinos and modified gravity with kinematic information
• Calculation of the critical overdensity in the spherical-collapse approximation
• The SRG-eROSITA All-Sky Survey : Constraints on f(R) Gravity from Cluster Abundance
• Parametrizations for tests of gravity
• Gravitational collapse of massless scalar field in $f(R)$ gravity
• Mass accretion rates of clusters of galaxies: CIRS and HeCS
• fkPT: Constraining scale-dependent modified gravity with the full-shape galaxy power spectrum
• The Integrated Bispectrum in Modified Gravity Theories
• Dark Matter Halo Sparsity of Modified Gravity Scenarios
• Primordial Black Hole Merger Rate in $f(R)$ Gravity
• Equivalence between Scalar-Tensor theories and $f(R)$-gravity: From the action to Cosmological Perturbations
• Improved analytical modeling of the non-linear power spectrum in modified gravity cosmologies
• Quasi-spherical collapse of matter in $\Lambda$CDM
• The $f(R)$ halo mass function in the cosmic web
• Using large scale structure data and a halo model to constrain Generalised Dark Matter
• Collapse in $f(R)$ gravity and the method of $R$ matching
• One-point probability distribution function from spherical collapse: Early Dark Energy (EDE) vs. $\Lambda$CDM
• Gravitational collapse of compact stars in $f(R)=\xi R^4$ gravity
• On the galaxy 3-point correlation function in Modified Gravity
• Spherical vacuum and scalar collapse for the Starobinsky R^2 model
• Non-linear matter power spectrum without screening dynamics modelling in $f(R)$ gravity
• Universality of the halo mass function in screened gravity theories
• Non-linear density-velocity dynamics in $f(R)$ gravity from spherical collapse
• Viability of general relativity and modified gravity cosmologies using high-redshift cosmic probes
• Gravitational Collapse of Anisotropic Compact Stars in Modified $f(R)$ Gravity
• Top-Hat Spherical Collapse with Clustering Dark Energy. I. Radius Evolution and Critical Contrast Density
• Universality of the halo mass function in modified gravity cosmologies