Bianchi type VII_h models and the WMAP 3-year data

¹ Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, Postfach 1317, 85741 Garching bei München, Germany e-mail: [tjaffe;banday]@mpa-garching.mpg.de
² Institute of Theoretical Astrophysics, University of Oslo, PO Box 1029 Blindern, 0315 Oslo, Norway e-mail: [h.k.k.eriksen;f.k.hansen]@astro.uio.no
³ Centre of Mathematics for Applications, University of Oslo, PO Box 1053 Blindern, 0316 Oslo, Norway
⁴ JPL, M/S 169/327, 4800 Oak Grove Drive, Pasadena CA 91109, USA e-mail: Krzysztof.M.Gorski@jpl.nasa.gov
⁵ California Institute of Technology, Pasadena, CA 91125, USA
⁶ Warsaw University Observatory, Aleje Ujazdowskie 4, 00-478 Warszawa, Poland

Received: 2 June 2006
Accepted: 13 September 2006

Abstract

Context.A specific example of Bianchi type VII_h models, i.e. those including universal rotation (vorticity) and differential expansion (shear), has been shown in Jaffe et al. (2005, ApJ, 629, L1) to correlate unexpectedly with the WMAP first-year data.

Aims.We re-assess the signature of this model in the WMAP 3-year data.

Methods.The cross-correlation methods are described in Jaffe et al. (2006a, ApJ, 643, 616). We use the WMAP 3-year data release, including maps for individual years, and perform additional comparisons to assess the influence of both noise and residual foregrounds and eliminate potential non-cosmological sources for the correlation.

Results.We confirm that the signal is detected in both the combined 3-year data and the individual yearly sky maps at a level consistent with our original analysis. The significance of the correlation is not affected by either noise or foreground residuals.

Conclusions.The results of our previous study are unchanged.