Cosmological constraints on extended Galileon models

Journal Article · Thu Mar 01 00:00:00 EST 2012 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2012/03/025· OSTI ID:22279763

Felice, Antonio De ^[1]; Tsujikawa, Shinji ^[2]

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1. ThEP's CRL, NEP, The Institute for Fundamental Study, Naresuan University, Phitsanulok 65000 (Thailand)
2. Department of Physics, Faculty of Science, Tokyo University of Science, 1-3, Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan)

The extended Galileon models possess tracker solutions with de Sitter attractors along which the dark energy equation of state is constant during the matter-dominated epoch, i.e. w{sub DE} = −1−s, where s is a positive constant. Even with this phantom equation of state there are viable parameter spaces in which the ghosts and Laplacian instabilities are absent. Using the observational data of the supernovae type Ia, the cosmic microwave background (CMB), and baryon acoustic oscillations, we place constraints on the tracker solutions at the background level and find that the parameter s is constrained to be s = 0.034{sub −0.034}{sup +0.327} (95 % CL) in the flat Universe. In order to break the degeneracy between the models we also study the evolution of cosmological density perturbations relevant to the large-scale structure (LSS) and the Integrated-Sachs-Wolfe (ISW) effect in CMB. We show that, depending on the model parameters, the LSS and the ISW effect is either positively or negatively correlated. It is then possible to constrain viable parameter spaces further from the observational data of the ISW-LSS cross-correlation as well as from the matter power spectrum.

• OSTI ID: 22279763
• Journal Information: Journal of Cosmology and Astroparticle Physics, Vol. 2012, Issue 03; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ATTRACTORS
BARYONS
CORRELATIONS
COSMOLOGICAL MODELS
COSMOLOGY
DE SITTER GROUP
DE SITTER SPACE
DENSITY
DISTURBANCES
EQUATIONS OF STATE
LAPLACIAN
LIMITING VALUES
MATHEMATICAL SOLUTIONS
NONLUMINOUS MATTER
OSCILLATIONS
PHANTOMS
RELICT RADIATION
SUPERNOVAE
UNIVERSE