Constraints on the sound speed of dark energy

  title={Constraints on the sound speed of dark energy},
  author={Steen Hannestad},
  journal={Physical Review D},
We have studied constraints on the equation of state, w, and speed of sound, c{sub s}, of the dark energy from a joint analysis of data from the cosmic microwave background, large scale structure and type-Ia supernovae. We find that current observations have no significant sensitivity to c{sub s}. However, there is a slight difference between models in which there are no dark energy perturbations and models in which dark energy behaves as a fluid. Assuming that there are no dark energy… Expand

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