Formation gf Bosonic Compact Objects

TL;DR

This paper introduces gravitational cooling as a universal mechanism enabling the formation of bosonic compact objects, like boson stars, through gravitational interactions alone, with implications for dark matter and astrophysics.

Contribution

It demonstrates that gravitational cooling allows classical bosonic fields to form compact stars, providing a new formation mechanism for boson stars.

Findings

Gravitational cooling efficiently dissipates kinetic energy during collapse.

Bosonic stars can form without dissipation in the Klein-Gordon equation.

Implications for axion dark matter and cosmic abundance of bosonic objects.

Abstract

We showed that compact bosonic objects can be formed through a process we called gravitational cooling. A central issue in the subject of boson star is whether a classical field configuration, {\it e.g.,} one described by the Klein-Gordon equation, can collapse to form a compact star-like object, as there is apparently no dissipation in the Klein-Gordon equation. We demonstrated that there IS an efficient cooling mechanism to get rid of the kinetic energy for the formation of a compact object purely through the gravitational coupling, a mechanism universal to all self-graviting fields. Implications of this mechanism are discussed, including the abundance of bosonic stars in the universe, and the possibility of ruling out the axion as a dark matter condidate.