G_2 cosmological models separable in non-comoving coordinates

TL;DR

This paper classifies and constructs new G_2 cosmological models with separable metrics in non-comoving coordinates, revealing solutions not expressible in comoving frames and expanding understanding of their properties.

Contribution

It introduces a full classification of G_2 models with separable metrics in non-comoving coordinates, including explicit solutions and their characteristics.

Findings

Identified models with separable metrics in non-comoving coordinates.

Provided explicit solutions and their properties.

Highlighted differences from comoving coordinate solutions.

Abstract

We study new separable orthogonally transitive abelian G_2 on S_2 models with two mutually orthogonal integrable Killing vector fields. For this purpose we consider separability of the metric functions in a coordinate system in which the velocity vector field of the perfect fluid does not take its canonical form, providing thereby solutions which are non-separable in comoving coordinates in general. Some interesting general features concerning this class of solutions are given. We provide a full classification for these models and present several families of explicit solutions with their properties.