iv : a st ro - p h / 05 02 11 0 v 4 2 2 Ju n 20 05 Cosmic Microwave Background , Accelerating Universe and Inhomogeneous Cosmology

We consider a cosmology in which a spherically symmetric large scale inhomogeneous enhancement or a void are described by an inhomogeneous metric and Einstein’s gravitational equations. For a flat matter dominated universe the inhomogeneous equations lead to luminosity distance and Hubble constant formulas that depend on the location of the observer. For a general inhomogeneous solution, it is possible for the deceleration parameter to differ significantly from the FLRW result. The deceleration parameter q0 can be interpreted as being q0 < 0 in a FLRW universe and be q0 > 0 (q0 = 1/2 for a flat matter dominated universe) as inferred from the inhomogeneous enhancement that is embedded in a FLRW universe. However, for a synchronous and comoving metric the vorticity is zero and the deceleration parameter q is positive and the universe is decelerating when the positive energy conditions are satisfied. The CMB temperature fluctuations across the sky can be unevenly distributed in the northern and southern hemispheres in the inhomogeneous matter dominated solution, in agreement with the analysis of the WMAP power spectrum data by several authors. The model can possibly explain the anomalous alignment of the quadrupole and octopole moments observed in the WMAP data. e-mail: [email protected]