Astrophysical Constraints on Dark Energy

TL;DR

This paper explores how dark energy influences astrophysical phenomena, particularly in isolated dwarf galaxies, and proposes using observable velocities to constrain dark energy density.

Contribution

It introduces a method to use satellite velocities in isolated dwarf galaxies to measure or limit dark energy density.

Findings

Dark energy can overcome gravity at ~23 kpc for 10^7 M_sun objects.

Satellite velocities in isolated dwarfs can constrain dark energy density.

Potential to detect dark energy effects in astrophysical observations.

Abstract

Dark energy (i.e., a cosmological constant) leads, in the Newtonian approximation, to a repulsive force which grows linearly with distance and which can have astrophysical consequences. For example, the dark energy force overcomes the gravitational attraction from an isolated object (e.g., dwarf galaxy) of mass $10^7 M_\odot$ at a distance of $~ 23$ kpc. Observable velocities of bound satellites (rotation curves) could be significantly affected, and therefore used to measure or constrain the dark energy density. Here, {\it isolated} means that the gravitational effect of large nearby galaxies (specifically, of their dark matter halos) is negligible; examples of isolated dwarf galaxies include Antlia or DDO 1903