Rotating Scalar Field and Formation of Bose Stars

TL;DR

This paper investigates how rotating, self-interacting bosonic dark matter clouds evolve into Bose stars, revealing the impact of angular momentum and self-interaction on formation times and angular momentum transfer.

Contribution

It provides numerical evidence on the effects of angular momentum and self-interaction on Bose star formation, extending previous analytical stability studies.

Findings

Gravitational condensation time depends on angular momentum and self-interaction strength.

No significant angular momentum transfer occurs for attractive or no self-interaction cases.

Angular momentum transfer is possible in the case of repulsive self-interaction.

Abstract

We study numerical evolutions of an initial cloud of self-gravitating bosonic dark matter with finite angular momentum and self-interaction in kinetic regime. It is demonstrated that such a system can undergo gravitational condensation and form a Bose star. The results show that the gravitational condensation time is strongly influenced by the presence of finite angular momentum or the strength of self-interaction. We find that in the cases related with attractive or no self-interaction, there is no significant transfer of angular momentum from the initial cloud to the formed star. However, for the case repulsive interaction our results indicate that such a angular-momentum transfer is possible. These results are consistent with the earlier analytical work where the stability of the rotating boson star was considered [Dmitriev et al. 2021].