Dipole anisotropies of IRAS galaxies and the contribution of a large-scale local void

Abstract

Recent observations of dipole anisotropies show that the velocity of the Local Group ($\Vec v_{\rm G}$) induced by the clustering of IRAS galax ies has an amplitude and direction similar to those of the velocity of Cosmic Microwave Background dipole anisotropy ($\Vec v_{\rm CMB}$), but the difference $| \Vec v_{\rm G} - \Vec v_{\rm CMB} |$ is still $\sim 170$ km/s, which is about 28% of $|\Vec v_{\rm CMB} |$. Here we consider the possibility that the origin of this difference comes from a hypothetical large-scale local void, with which we can account for the accelerating behavior of type Ia supernovae due to the spatial inhomogeneity of the Hubble constant without dark energies and derive the constraint to the model parameters of the local void. It is found as a result that the distance between the Local Group and the center of the void must be $(10--20)h^{-1}$ Mpc, whose accurate value depends on the background model parameters.

13 pages, 1 figure, to be published in ApJ 584, No.2 (2003)

References in corpus (6)

• Final Results from the Hubble Space Telescope Key Project to Measure the Hubble Constant
• Cosmological Parameter Extraction from the First Season of Observations with DASI
• Cosmological implications of the MAXIMA-I high resolution Cosmic Microwave Background anisotropy measurement
• The evolution of the galaxy distribution
• Analyses of Type Ia Supernova Data in Cosmological Models with a Local Void
• Luminous Matter Distribution, Bulk Flows and Baryon Contents in Cosmological Models with a Local Void

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• Constraints on large scale inhomogeneities from WMAP-5 and SDSS: confrontation with recent observations
• Reconciling the local void with the CMB
• Swiss Cheese and a Cheesy CMB
• Is the evidence for dark energy secure?
• Probing violation of the Copernican principle via the integrated Sachs-Wolfe effect