Modelling non-dust fluids in cosmology

Abstract

Currently, most of the numerical simulations of structure formation use Newtonian gravity. When modelling pressureless dark matter, or `dust', this approach gives the correct results for scales much smaller than the cosmological horizon, but for scenarios in which the fluid has pressure this is no longer the case. In this article, we present the correspondence of perturbations in Newtonian and cosmological perturbation theory, showing exact mathematical equivalence for pressureless matter, and giving the relativistic corrections for matter with pressure. As an example, we study the case of scalar field dark matter which features non-zero pressure perturbations. We discuss some problems which may arise when evolving the perturbations in this model with Newtonian numerical simulations and with CMB Boltzmann codes.

5 pages; v2: typos corrected and refs added, submitted version; v3: version to appear in JCAP

References in corpus (34)

• Efficient Computation of CMB anisotropies in closed FRW models
• Large-Scale Structure of the Universe and Cosmological Perturbation Theory
• Cold and Fuzzy Dark Matter
• Perturbations in k-inflation
• Ghost Condensation and a Consistent Infrared Modification of Gravity
• Cosmological perturbations
• Purely kinetic k-essence as unified dark matter
• A New Cosmological Model of Quintessence and Dark Matter
• The Cosmic Linear Anisotropy Solving System (CLASS) I: Overview
• Structure Formation with Generalized Dark Matter
• Large-scale instability in interacting dark energy and dark matter fluids
• A Further Analysis of a Cosmological Model of Quintessence and Scalar Dark Matter
• Dust of Dark Energy
• The Mass Power Spectrum in Quintessence Cosmological Models
• High-Resolution Simulation on Structure Formation with Extremely Light Bosonic Dark Matter
• Connection between Newtonian simulations and general relativity
• The dark degeneracy and interacting cosmic components
• Inflation, dark matter and dark energy in the string landscape
• The Structure of Structure Formation Theories
• Unified Dark Matter in Scalar Field Cosmologies
• Noninteracting dark matter
• The non-adiabatic pressure in general scalar field systems
• Scale-dependent bias from primordial non-Gaussianity in general relativity
• How the Scalar Field of Unified Dark Matter Models Can Cluster
• Generalizing a Unified Model of Dark Matter, Dark Energy, and Inflation with Non Canonical Kinetic Term
• Structure formation with scalar field dark matter: the field approach
• Bose-Einstein condensation of relativistic Scalar Field Dark Matter
• Lukewarm dark matter: Bose condensation of ultralight particles
• A Concise Introduction to Perturbation Theory in Cosmology
• Structure Formation with Scalar Field Dark Matter: The Fluid Approach
• Covariant Linear Perturbation Formalism
• Scalar Field Dark Matter
• Scalar field-perfect fluid correspondence and nonlinear perturbation equations
• Gauge conditions in combined dark energy and dark matter systems

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