Constraints on the dark matter sound speed from galactic scales: the cases of the Modified and Extended Chaplygin Gas

Abstract

We show that the observed rotation curves of spiral galaxies constrain the sound speed of the dark matter to be $c_s<10^{-4}c$, where $c$ is the speed of light in vacuum. Using the Modified Chaplygin Gas as a representative example of a class of unified dark energy models incorporating an effective dark matter component with a non-zero sound speed, we determine the most stringent constraint to date on the value of the constant contribution to the equation of state parameter in this class of models. Finally, we explain the reason why previous constraints using the Cosmic Microwave Background and Baryonic Acoustic Oscillations were not as competitive as the one presented in this paper and discuss the limitations of the recently proposed Extended Chaplygin Gas.

4 pages

References in corpus (13)

• Dynamics of dark energy
• Dark energy cosmology: the equivalent description via different theoretical models and cosmography tests
• Dark Energy and the Accelerating Universe
• Constraints on modified Chaplygin gas from recent observations and a comparison of its status with other models
• $\Lambda \alpha$DM: Observational constraints on unified dark matter with constant speed of sound
• Modified Chaplygin Gas as a Unified Dark Matter and Dark Energy Model and Cosmic Constraints
• Nonlinear Chaplygin Gas Cosmologies
• Combined constraints on modified Chaplygin gas model from cosmological observed data: Markov Chain Monte Carlo approach
• Ruling out the Modified Chaplygin Gas Cosmologies
• ISW effect in Unified Dark Matter Scalar Field Cosmologies: an analytical approach
• Linear and non-Linear Instabilities in Unified Dark Energy Models
• Clustering Properties of Dynamical Dark Energy Models
• Vacuum energy sequestering and cosmic dynamics

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• On the Square Speed of Sound in High-Energy Collisions: Range of Values and How to Understand It