Limits to Global Rotation and Shear From the COBE DMR 4-Year Sky Maps
Abstract
Small departures from a homogeneous isotropic spacetime create observable features in the large-scale anisotropy of the cosmic microwave background. We cross-correlate the maps of the cosmic microwave background anisotropy from the Cosmic Background Explorer (COBE) Differential Microwave Radiometers (DMR) 4-year data set with template maps from Bianchi VII_h cosmological models to limit global rotation or shear in the early universe. On the largest scales, spacetime is well described by the Friedmann-Robertson-Walker metric, with departures from isotropy about each spatial point limited to shear sigma/H_0 < 10^{-9} and rotation omega/H_0 < 6 x 10^{-8} for 0.1 < Omega_0 < 1.
Cite
@article{arxiv.astro-ph/9701090,
title = {Limits to Global Rotation and Shear From the COBE DMR 4-Year Sky Maps},
author = {A. Kogut and G. Hinshaw and A. J. Banday},
journal= {arXiv preprint arXiv:astro-ph/9701090},
year = {2009}
}
Comments
10 pages LaTeX including 3 PostScript figures using psfig style macro. To appear in Physical Review D15