Slowly Rotating Boson Stars

TL;DR

This paper develops a numerical method for modeling slowly rotating boson stars using the Einstein-Klein Gordon system, analyzing their physical properties and particle dynamics, and comparing with fully rotating solutions.

Contribution

It introduces a simplified slow-rotation approximation for boson stars, enabling efficient numerical solutions and detailed physical analysis.

Findings

Sequences of solutions with varying mass and angular momentum

Physical properties like compactness are characterized

Comparison shows the approximation's validity range

Abstract

We present solutions to the Einstein-Klein Gordon system representing boson stars in the slow rotation approximation. By considering slow rotation we are able to reduce the number of equations yielding a system of ordinary differential equations that is conveniently solved numerically without the need of expensive computational resources. We find sequences of solutions and describe some of their physical properties such as, total mass, angular momentum and compactness. We also consider the dynamics of particles (geodesics) in the resulting spacetime. A detailed comparison with fully rotating boson stars (non-linear treatment) is performed by showing the region of validity of the slow-rotation approximation.