Do the cosmological observational data prefer phantom dark energy?

The dynamics of expansion and large-scale structure formation of the Universe are analyzed for models with dark energy in the form of a phantom scalar field which initially mimics a [Lambda]-term and evolves slowly to the Big Rip singularity. The discussed model of dark energy has three parameters-t...

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Bibliographic Details
Published in:Physical review. D, Particles, fields, gravitation, and cosmology Particles, fields, gravitation, and cosmology, 2012-10, Vol.86 (8), Article 083008
Main Authors: Novosyadlyj, Bohdan, Sergijenko, Olga, Durrer, Ruth, Pelykh, Volodymyr
Format: Article
Language:English
Subjects:
Cosmic microwave background
Dark energy
Density
Equations of state
Gravitation
Mathematical models
Scalars
Singularities
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Summary:The dynamics of expansion and large-scale structure formation of the Universe are analyzed for models with dark energy in the form of a phantom scalar field which initially mimics a [Lambda]-term and evolves slowly to the Big Rip singularity. The discussed model of dark energy has three parameters-the density and the equation of state parameter at the current epoch, [Omega] sub(de) and w sub(0), and the asymptotic value of the equation of state parameter at a arrow right [infinity], (ProQuest: Formulae and/or non-USASCII text omitted). Their best-fit values are determined jointly with all other cosmological parameters by the Markov chain Monte Carlo method using observational data on cosmic microwave background anisotropies and polarization, supernovae type Ia luminosity distances, baryon acoustic oscillations measurements, and more. Similar computations are carried out for [Lambda] CDM and a quintessence scalar field model of dark energy. It is shown that the current data slightly prefer the phantom model, but the differences in the maximum likelihoods are not statistically significant. It is also shown that the phantom dark energy with monotonically increasing density in the future will cause the decay of large-scale linear matter density perturbations due to the gravitational domination of dark energy perturbations long before the Big Rip singularity.
ISSN:1550-7998
1550-2368
DOI:10.1103/PhysRevD.86.083008