Cosmic Microwave Background Quadrupole and Ellipsoidal Universe

TL;DR

This paper explores how an ellipsoidal universe model with axis symmetry can naturally suppress the CMB quadrupole, aligning theoretical predictions with observations and constraining the universe's anisotropic parameters.

Contribution

It provides a detailed analysis of the CMB quadrupole anisotropy in an axis-symmetric universe, improving constraints on the universe's eccentricity and symmetry axis direction.

Findings

Quadrupole amplitude can match observations with eccentricity ~0.0035.

Direction of symmetry axis aligns with recent CMB analyses.

Tighter constraints on universe's anisotropic parameters.

Abstract

Recent Wilkinson Microwave Anisotropy Probe (WMAP) data confirm the Cosmic Microwave Background (CMB) quadrupole anomaly. We further elaborate our previous proposal that the quadrupole power can be naturally suppressed in axis-symmetric universes. In particular, we discuss in greater detail the CMB quadrupole anisotropy and considerably improve our analysis. As a result, we obtain tighter constraints on the direction of the axis of symmetry as well as on the eccentricity at decoupling. We find that the quadrupole amplitude can be brought in accordance with observations with an eccentricity at decoupling of about 0.35 10^{-2}. Moreover, our determination of the direction of the symmetry axis is in reasonable agreement with recent statistical analyses of cleaned CMB temperature fluctuation maps obtained by means of improved internal linear combination methods as Galactic foreground subtraction technique.