Anisotropy of the Hubble Constant in a Cosmological Model with a Local Void on Scales of ~ 200 Mpc

摘要

A spherical cosmological model with a local void on scales of $\sim 200$ Mpcand with an inhomogeneous Hubble constant was proposed in recent two papers.This model explains consistently the observed properties of the cosmic bulkflow, the accelerating behavior of type Ia supernovae and the CMB dipoleanisotropy without invoking a cosmological constant. As we are in a positiondeviated from the center in the model, the anisotropy of the Hubble constantappears owing to the directional difference of the distance from the observerto the boundary of the void region. It is found that the anisotropy ismaximally about 6% of the constant in the region of $200 \sim 500$ Mpc from us.This inhomogeneity and anisotropy of the Hubble constant are not so large as tobe inconsistent with the present observation. The detection of this anisotropyin the future will be useful to clarify the implication of the inhomogeneity ofthe Hubble constant.