A method to search for topological signatures in the angular distribution of cosmic objects

Instituto Nacional de Pesquisas Espaciais, Divisão de Astrofísica, Av. dos Astronautas 1758, 12227-010, São José dos Campos, SP, Brazil e-mail: [bernui;thyrso]@das.inpe.br

Received: 5 September 2004
Accepted: 30 September 2004

Abstract

We present a method to search for large angular-scale correlations, termed topological signatures, in the angular distribution of cosmic objects, which does not depend on cosmological models or parameters and is based only on the angular coordinates of the objects. In order to explore Cosmic Microwave Background temperature fluctuations data, we applied this method to simulated distributions of objects in thin spherical shells located in three dif ferent multiply-connected Euclidean 3-spaces (T³, , and G₆), and found that the topological signatures due to these topologies can be revealed even if their intensities are small. We show how to detect such signatures for the cases of full-sky and partial-sky distributions of objects. This method can also be applied to other ensembles of cosmic objects, like galaxies or quasars, in order to reveal possible angular-scale correlations in their distributions.