Confronting Dark Energy Anisotropic Stress

Abstract

We use the currently available cosmic observations to probe and constrain an imperfect dark energy fluid which is characterized by a constant equation of state $w$ and a constant speed of viscosity $c_{vis}^2$. The model parameter space was scanned by using Markov chain Monte Carlo method. The results show that the speed of viscosity $c_{vis}^2$ was not well constrained when currently available date sets, which include the cosmic microwave background radiation from {\it Planck}2013, type Ia supernovae and baryon acoustic oscillations, are used. But the cosmic data sets favor phantom dark energy with a negative speed of viscosity $c_{vis}^2$ slightly.

5 pages, 2 figures, code bugs removed, references added, CAMB code modification was described briefly

References in corpus (3)

• Constraining Dark Energy Anisotropic Stress
• Future CMB Constraints on Early, Cold, or Stressed Dark Energy
• A combined analysis of 3D Weak Lensing, Lyman-alpha forest and WMAP year three data

Cited by in corpus (2)

• On the current status of Modified Gravity
• Current constraints on early and stressed dark energy models and future 21 cm perspectives