Consistency analysis of a Dark Matter velocity dependent force as an alternative to the Cosmological Constant

Abstract

A range of cosmological observations demonstrate an accelerated expansion of the Universe, and the most likely explanation of this phenomenon is a cosmological constant. Given the importance of understanding the underlying physics, it is relevant to investigate alternative models. This article uses numerical simulations to test the consistency of one such alternative model. Specifically, this model has no cosmological constant, instead the dark matter particles have an extra force proportional to velocity squared, somewhat reminiscent of the magnetic force in electrodynamics. The constant strength of the force is the only free parameter. Since bottom-up structure formation creates cosmological structures whose internal velocity dispersions increase in time, this model may mimic the temporal evolution of the effect from a cosmological constant. It is shown that models with force linearly proportional to internal velocites, or models proportional to velocity to power three or more cannot mimic the accelerated expansion induced by a cosmological constant. However, models proportional to velocity squared are still consistent with the temporal evolution of a Universe with a cosmological model.

arXiv comment5 pages, 3 figures, ApJ format

References in corpus (14)

• Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant
• Measurements of Omega and Lambda from 42 High-Redshift Supernovae
• Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Particle Dark Matter: Evidence, Candidates and Constraints
• Cosmological Hydrodynamics with Adaptive Mesh Refinement: a new high resolution code called RAMSES
• Baryon Acoustic Oscillations in the Sloan Digital Sky Survey Data Release 7 Galaxy Sample
• Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Power Spectra and WMAP-Derived Parameters
• A Multi-Code Analysis Toolkit for Astrophysical Simulation Data
• Improved Dark Energy Constraints from ~100 New CfA Supernova Type Ia Light Curves
• Multi-scale initial conditions for cosmological simulations
• The WiggleZ Dark Energy Survey: the growth rate of cosmic structure since redshift z=0.9
• HOP: A New Group-Finding Algorithm for N-body Simulations
• The WiggleZ Dark Energy Survey: measuring the cosmic expansion history using the Alcock-Paczynski test and distant supernovae
• The Dark Matter equation of state through cosmic history

Cited by in corpus (5)

• Brief Review of Recent Advances in Understanding Dark Matter and Dark Energy
• General spherically symmetric solution of Cotton gravity
• Accelerated expansion induced by Dark Matter with two charges
• A force proportional to velocity squared derived from spacetime algebra
• Unified description of galactic dynamics and the cosmological constant