Turnaround physics beyond spherical symmetry

TL;DR

This paper generalizes the concept of turnaround surfaces in accelerating universes beyond spherical symmetry, bridging theoretical models and real astronomical observations, and extends previous results to scalar-tensor gravity.

Contribution

It introduces a generalized framework for turnaround surfaces applicable to non-spherical geometries and extends existing results to scalar-tensor gravity theories.

Findings

Successfully generalizes turnaround surface concept beyond spherical symmetry.

Recovers previous results in small deviations case.

Extends analysis to scalar-tensor gravity theories.

Abstract

The concept of turnaround surface in an accelerating universe is generalized to arbitrarily large deviations from spherical symmetry, to close the gap between the idealized theoretical literature and the real world observed by astronomers. As an analytical application, the characterization of turnaround surface is applied to small deviations from spherical symmetry, recovering a previous result while extending it to scalar-tensor gravity.