Consistency Analysis of a Dark Matter Velocitydependent 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 the velocity squared, somewhat reminiscent of the magnetic force in electrodynamics. The constant strength of the force is the only free parameter. Because bottomup 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 velocities, or models proportional to velocity to power 3 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.
 Publication:

The Astrophysical Journal
 Pub Date:
 April 2021
 DOI:
 10.3847/15384357/abe5a2
 arXiv:
 arXiv:2102.07792
 Bibcode:
 2021ApJ...910...98L
 Keywords:

 Dark matter;
 Cosmology;
 Accelerating universe;
 353;
 343;
 12;
 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 5 pages, 3 figures, ApJ format