Testing the isotropy of the universe by using the JLA compilation of type ia supernovae

Abstract

We probe the possible anisotropy of the Universe by using the joint light-curve analysis (JLA) compilation of Type Ia supernovae. We apply the Markov Chain Monte Carlo method to constrain the amplitude and direction of anisotropy in three cosmological models. For the dipole-modulated (n-ary logical and) cold dark matter ((n-ary logical and)CDM) model, the anisotropic amplitude is consistent with zero at 68 per cent cl, and has an upper bound AD < 1.98 × 10-3 at 95 per cent cl. Regardless of much larger uncertainty, we amazingly find that the dipole direction of JLA is almost opposite to that of Union2. Similar results are found for the dipole-modulated wCDM and Chevallier-Polarski-Linder (CPL) models. Thus, the Universe is still well consistent with the isotropy according to the JLA compilation.