Abstract
We analyze the magnitude-redshift data of type Ia supernovae included in the Union and Union2 compilations in the framework of an anisotropic Bianchi type I cosmological model and in the presence of a dark-energy fluid with anisotropic equation of state. We find that the amount of deviation from isotropy of the equation of state of dark energy, the skewness , and the present level of anisotropy of the large-scale geometry of the Universe, the actual shear , are constrained in the ranges and ( C.L.) by Union2 data. Supernova data are then compatible with a standard isotropic universe (), but a large level of anisotropy, both in the geometry of the Universe and in the equation of state of dark energy, is allowed.
- Received 17 January 2011
DOI:https://doi.org/10.1103/PhysRevD.83.103503
© 2011 American Physical Society