EDP Sciences
Free access
Volume 490, Number 3, November II 2008
Page(s) 929 - 932
Section Cosmology (including clusters of galaxies)
DOI http://dx.doi.org/10.1051/0004-6361:200810747
Published online 17 September 2008

A&A 490, 929-932 (2008)
DOI: 10.1051/0004-6361:200810747

Large scale plane-mirroring in the cosmic microwave background WMAP5 maps

V. G. Gurzadyan1, 2, A. A. Starobinsky3, T. Ghahramanyan1, A. L. Kashin1, H. G. Khachatryan1, H. Kuloghlian1, D. Vetrugno4, and G. Yegorian1

1  Yerevan Physics Institute and Yerevan State University, Yerevan, Armenia
    e-mail: gurzadya@icra.it
2  ICRANet, ICRA, University “La Sapienza”, Rome, Italy
3  Landau Institute for Theoretical Physics, Moscow, 119334, Russia
4  University of Lecce, Lecce, Italy

Received 5 August 2008 / Accepted 20 August 2008

We continue investigation of the hidden plane-mirror symmetry in the distribution of excursion sets in cosmic microwave background (CMB) temperature anisotropy maps, previously noticed in the three-year data of the Wilkinson microwave anisotropy probe (WMAP), using the WMAP 5 years maps. The symmetry is shown to have higher significance, $\chi^2 < 1.7$, for low multipoles $\ell < 5$, while disappearing at larger multipoles, $\chi^2 >
3.5 $ for $\ell > 10$. The study of the sum and difference maps of temperature inhomogeneity regions, along with simulated maps, confirms its existence. The properties of these mirroring symmetries are compatible with those produced by the Sachs-Wolfe effect in the presence of an anomalously large component of horizon-size density perturbations, independent of one of the spatial coordinates, and/or a slab-like spatial topology of the Universe.

Key words: cosmology: cosmic microwave background

© ESO 2008