A survey of lens spaces and large-scale CMB anisotropy

TL;DR

This paper surveys lens space topologies and their impact on large-scale CMB anisotropy suppression, identifying specific lens spaces that match observed CMB features better than simply connected models.

Contribution

It systematically analyzes lens spaces L(p,q) with p<=72 and their effects on CMB anisotropy, providing new candidate topologies for explaining observed suppression.

Findings

Certain lens spaces suppress large-scale CMB correlations by a factor of two.

Some lens spaces match WMAP 7-year data better than simply connected models.

The study extends the range of topologies considered for cosmological implications.

Abstract

The cosmic microwave background (CMB) anisotropy possesses the remarkable property that its power is strongly suppressed on large angular scales. This observational fact can naturally be explained by cosmological models with a non-trivial topology. The paper focuses on lens spaces L(p,q) which are realised by a tessellation of the spherical 3-space S^3 by cyclic deck groups of order p<=72. The investigated cosmological parameter space covers the interval Omega_tot \in [1.001,1.05]. Several spaces are found which have CMB correlations on angular scales theta >= 60^\circ suppressed by a factor of two compared to the simply connected S^3 space. The analysis is based on the S statistics, and a comparison to the WMAP 7yr data is carried out. Although the CMB suppression is less pronounced than in the Poincare dodecahedral space, these lens spaces provide an alternative worth for follow-up studies.