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More information for the discussion.

Amara

http://xxx.uni-augsburg.de/abs/gr-qc/0105002

General Relativity and Quantum Cosmology, abstract

gr-qc/0105002

From: "Marcelo J. Reboucas" <reboucas@cbpf.br>

Date: Wed, 2 May 2001 00:49:39 GMT (147kb)

Detectability of Cosmic Topology in Almost Flat Universes

Authors: G.I. Gomero, M.J. Reboucas, R. Tavakol

Comments: 18 pages, 3 figures, LaTeX2e

Recent observations suggest that the ratio of the total density to

the critical density of the universe, $\Omega_0$, is likely to be

very close to one, with a significant proportion of this energy

being in the form of a dark component with negative pressure.

Motivated by this result, we study the question of observational

detection of possible non-trivial topologies in universes with

$\Omega_0 \sim 1$, which include a cosmological constant. Using a

number of indicators we find that as $\Omega_0 \to 1$, increasing

families of possible topologies become either undetectable or can

be excluded observationally. Furthermore, given a non-zero lower

bound on $|\Omega_0 - 1|$, we can rule out families of topologies

as possible candidates for the shape of our universe. We

demonstrate these findings concretely by considering families of

topologies and employing bounds on cosmological parameters from

recent observations. We find that given the present bounds on

cosmological parameters, there are families of both hyperbolic and

spherical manifolds that remain undetectable and families that can

be excluded as the shape of our universe. These results are of

importance in future search strategies for the detection of the

shape of our universe, given that there are an infinite number of

theoretically possible topologies and that the future observations

are expected to put a non-zero lower bound on $|\Omega_0 - 1|$

which is more accurate and closer to zero.

Paper: Source (147kb), PostScript, or Other formats

--********************************************************************* Amara Graps | Max-Planck-Institut fuer Kernphysik Interplanetary Dust Group | Saupfercheckweg 1 +49-6221-516-543 | 69117 Heidelberg, GERMANY Amara.Graps@mpi-hd.mpg.de * http://www.mpi-hd.mpg.de/dustgroup/~graps ********************************************************************* "Never fight an inanimate object." - P. J. O'Rourke

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