Testing the isotropy of the Universe with type Ia supernovae in a model-independent way

Abstract

In this paper, we study an anisotropic universe model with Bianchi-I metric using Joint Light-curve Analysis (JLA) sample of type Ia supernovae (SNe Ia). Because light-curve parameters of SNe Ia vary with different cosmological models and SNe Ia samples, we fit the SNe Ia light-curve parameters and cosmological parameters simultaneously employing Markov Chain Monte Carlo method. Therefore, the results on the amount of deviation from isotropy of the dark energy equation of state ($\delta$), and the level of anisotropy of the large-scale geometry (${\Sigma }_0$) at present, are totally model-independent. The constraints on the skewness and cosmic shear are $-0.101<\delta <0.071$ and $-0.007<{\Sigma }_0<0.008$. This result is consistent with a standard isotropic universe ($\delta ={\Sigma }_0=0$). However, a moderate level of anisotropy in the geometry of the Universe and the equation of state of dark energy, is allowed. Besides, there is no obvious evidence for a preferred direction of anisotropic axis in this model.

10 pages, 5 figures, 5 tables, accepted for publication in MNRAS

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Cited by in corpus (13)

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• Constraints on a Bianchi type I spacetime extension of the standard $\Lambda$CDM model
• Testing spatial curvature and anisotropic expansion on top of the $\Lambda$CDM model
• Anisotropy of the Universe via the Pantheon supernovae sample revisited
• Constraining the anisotropy of the Universe via Pantheon supernovae sample
• Percent-Level Test of Isotropic Expansion Using Type Ia Supernovae
• Bianchi Type I model of universe with customized scale factors
• Consistency of Pantheon+ supernovae with a large-scale isotropic universe
• Anisotropic universe with anisotropic dark energy
• Anisotropic Scalar Field Dark Energy with a Disformally Coupled Yang-Mills Field
• Bianchi IX gravitational collapse of matter inhomogeneities
• Dynamical systems analysis of an interacting scalar field model in an anisotropic universe
• $\Lambda$CDM cosmology with a quiescent anisotropy in a higher dimensional steady state universe