PROGRAMA DE PÓS-GRADUAÇÃO EM FÍSICA (CCEN - PPGF)
CENTRO DE CIÊNCIAS EXATAS E DA NATUREZA (CCEN)
- Telefone/Ramal
- Não informado
Notícias
Colóquio: Limits in the determination of the finiteness of the universe (Prof. Dr. Marcelo J. Rebouças - CBPF)
| An important observable prediction of a detectable nontrivial spatial topology of the Universe is the presence in the cosmic microwave background sky of pairs of matching circles with the same distributions of temperature fluctuations — the so-called circles-in-the-sky. In the most general search for these circles, pairs of circles with deviation from antipodality 0◦ ≤ θ ≤ 170◦ and radii 10◦ ≤ λ ≤ 90◦ were investigated, but no matching circles were found. We examine the question as to whether there are nearly flat universes with compact topology that would give rise to circles whose observable parameters λ and θ fall o outside the ranges covered by this general search. We show that no matter how nearly flat the Universe is, it can always have a nontrivial spatial topology that gives rise to circles whose deviation from antipodality θ is larger than 170◦ , and whose radii of the circles λ are smaller than 10◦ for some observers’s positions. This makes apparent that the circles-in-the-sky searches carried out so far with either WMAP or Planck data are not sufficient to exclude the possibility of a universe with detectable nontrivial cosmic topology. We also present concrete examples of such finite universes with cosmological parameters given by Planck collaboration. |