Can the Lack of Symmetry in the COBE DMR Maps Constrain the Topology of the Universe?
Abstract
Although the cubic T^{3} "small universe" has been ruled out by COBE Differential Microwave Radiometer (DMR) results as an interesting cosmological model, we still have the possibility of living in a universe with a more anisotropic topology, such as a rectangular T^{3} "small universe" with one or two of its dimensions significantly smaller than the present horizon (which we refer to as T^{1} and T^{2} models, respectively). In order to rule out these anisotropic topologies as well, we apply a new data analysis method that searches for the specific kind of symmetries that these models should produce. We find that the 4 year COBE DMR data place a lower limit on the smallest cell size for T^{1} and T^{2} models of 3000 h^{1} Mpc, at 95% confidence, for a scaleinvariant power spectrum (n = 1). These results imply that all toroidal universes (cubes and rectangles) are ruled out as interesting cosmological models.
 Publication:

The Astrophysical Journal
 Pub Date:
 September 1996
 DOI:
 10.1086/177706
 arXiv:
 arXiv:astroph/9510109
 Bibcode:
 1996ApJ...468..457D
 Keywords:

 COSMOLOGY: COSMIC MICROWAVE BACKGROUND;
 COSMOLOGY: LARGESCALE STRUCTURE OF UNIVERSE;
 COSMOLOGY: OBSERVATIONS;
 Astrophysics;
 General Relativity and Quantum Cosmology
 EPrint:
 Minor revisions to match published version. 14 pages, with 4 figures included. Color figures and links at http://www.sns.ias.edu/~angelica/topology.html