Universität Ulm

Friday, 14

Lecture hall (Sal) F, Sölvegatan 14

The temperature fluctuations of the cosmic microwave background radiation (CMB) will be discussed, in particular, "the mystery of the missing fluctuations" at large scales, first observed by COBE and nicely confirmed by the first-year data of NASA's explorer mission "Wilkinson Microwave Anisotropy Probe" (WMAP). We show that these data hint that our Universe might possess a non-trivial spatial topology. Two nearly flat models are discussed: the Picard space which is stretched out into an infinitely long horn, but with finite volume, and the Poincaré dodecahedron. Both models predict the observed suppression of power at large scales. As a signature of cosmic topology, one should find pairs of matching circles in the CMB sky maps.

References:

R. Aurich, S. Lustig, F. Steiner and H. Then

Class. Quant. Grav.

to appear in Phys. Rev. Lett, astro-ph/0412407

R. Aurich, S. Lustig and F. Steiner

CMB Anisotropy of the Poincaré Dodecahedron

astro-ph/0412569

The Colloquia in Theoretical Physics are aimed for a general audience of students, teachers and researchers interested in physics and the laws of Nature. Coffee will be served after the Colloquium.

Gösta Gustafson -- Theoretical physics

Sven Åberg -- Mathematical physics

Last modified: Dec 22 2004 Stefan Keppeler (stefan.keppeler@matfys.lth.se)