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تسجيل مستخدم جديدThe optimal phase of the generalised Poincare dodecahedral space hypothesis implied by the spatial cross-correlation function of the WMAP sky maps
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تأليف
Boudewijn F. Roukema
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Several studies have proposed that the shape of the Universe may be a Poincare dodecahedral space (PDS) rather than an infinite, simply connected, flat space. Both models assume a close to flat FLRW metric of about 30% matter density. We study two predictions of the PDS model. (i) For the correct model, the spatial two-point cross-correlation function, $ximc$, of temperature fluctuations in the covering space, where the two points in any pair are on different copies of the surface of last scattering (SLS), should be of a similar order of magnitude to the auto-correlation function, $xisc$, on a single copy of the SLS. (ii) The optimal orientation and identified circle radius for a generalised PDS model of arbitrary twist $phi$, found by maximising $ximc$ relative to $xisc$ in the WMAP maps, should yield $phi in {pm 36deg}$. We optimise the cross-correlation at scales < 4.0 h^-1 Gpc using a Markov chain Monte Carlo (MCMC) method over orientation, circle size and $phi$. Both predictions were satisfied: (i) an optimal generalised PDS solution was found, with a strong cross-correlation between points which would be distant and only weakly correlated according to the simply connected hypothesis, for two different foreground-reduc
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