A test of the Poincaré dodecahedral space topology hypothesis with the WMAP CMB data^*

¹ Toruń Centre for Astronomy, Nicolaus Copernicus University, ul. Gagarina 11, 87-100 Toruń, Poland
² Department of Physics and Astrophysics, Nagoya University, Nagoya 464-8602, Japan e-mail: blew@a.phys.nagoya-u.ac.jp

Received: 2 October 2007
Accepted: 7 January 2008

Abstract

It has been suggested by Roukema and coworkers (hereafter R04) that the topology of the Universe as probed by the “matched circles” method using the first year release of the WMAP CMB data, might be that of the Poincaré dodecahedral space (PDS) model. An excess in the correlation of the “identified circles” was reported by R04, for circles of angular radius of ~11° for a relative phase twist -36°, hinting that this could be due to a Clifford translation, if the hypothesized model were true. R04 did not however specify the statistical significance of the correlation signal. We investigate the statistical significance of the signal using Monte Carlo CMB simulations in a simply connected Universe, and present an updated analysis using the three-year WMAP data. We find that our analyses of the first and three year WMAP data provide results that are consistent with the simply connected space at a confidence level as low as 68%.