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Indexed by:期刊论文

Date of Publication:2013-04-02

Journal:PHYSICAL REVIEW D

Included Journals:SCIE、Scopus

Volume:87

Issue:8

ISSN No.:2470-0010

Abstract:Any unified dark matter cosmology can be decomposed into dark matter interacting with vacuum energy, without introducing any additional degrees of freedom. We present observational constraints on an interacting vacuum plus dark energy corresponding to a generalized Chaplygin gas cosmology. We consider two distinct models for the interaction leading to either a barotropic equation of state or dark matter that follows geodesics, corresponding to a rest-frame sound speed equal to the adiabatic sound speed or zero sound speed, respectively. For the barotropic model, the most stringent constraint on alpha comes from the combination of CMB + SNIa + LSS(m) gives alpha < 5.66 x 10(-6) at the 95% confidence level, which indicates that the barotropic model must be extremely close to the Lambda CDM cosmology. For the case where the dark matter follows geodesics, perturbations have zero sound speed, and CMB + SNIa + gISW then gives the much weaker constraint -0.15< alpha < 0.26 at the 95% confidence level. DOI:10.1103/PhysRevD.87.083503