Rong-Gen Cai, Yin-Zhe Ma, Bo Tang, Zhong-Liang Tuo
We study the possibly existing anisotropy in the accelerating expansion Universe with the Union2 Type Ia supernovae data and Gamma-ray burst data. We construct a direction-dependent dark energy model and constrain the anisotropy direction and strength of modulation. We find that the maximum anisotropic deviation direction is $(l,\,b)=(126^{\circ},\,13^{\circ})$ (or equivalently $(l,\,b)=(306^{\circ},\,-13^{\circ})$), and the anisotropy level is $g_0=0.030_{+0.010}^{-0.030}$ (obtained using Union2 data, at $1\sigma$ confidence level). Our results do not show strong evidence for the anisotropic dark energy model. We also discuss potential methods that may distinguish the peculiar velocity field from the anisotropic dark energy model.
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http://arxiv.org/abs/1303.0961
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