Gravipulsons

TL;DR

This paper investigates self-gravitating oscillating scalar field lumps called pulsons within a logarithmic potential, deriving solutions using asymptotic expansion, analyzing their stability, and exploring their potential astrophysical relevance.

Contribution

It introduces a method to find pulson solutions in the Einstein-Klein-Gordon system using asymptotic expansion and identifies conditions for their periodicity and long-term stability.

Findings

Pulson solutions are expressed via solutions of the singular Hill's equation.

Conditions for periodic pulson solutions are identified.

Numerical simulations show long-lived periodic pulsons form under certain initial conditions.

Abstract

We search for self-gravitating oscillating field lumps (pulsons) in the scalar model with logarithmic potential. With the use of a Krylov-Bogoliubov-type asymptotic expansion in the gravitational constant, the pulson solutions of the Einstein-Klein-Gordon system are obtained in the Schwarzschild coordinates. They are expressed in terms of solutions of the singular Hill's equation. The masses of the obtained pulsons are calculated. The initial conditions are found under which the pulson solutions become periodic. These conditions are then used in direct numerical integration of the Einstein-Klein-Gordon system. It is shown that they do evolve into a very long-lived periodic pulson. Stability of the self-gravitating pulsons and their possible astrophysical applications are briefly discussed.