Robustness of particle creation in the formation of a compact object

TL;DR

This paper investigates the robustness of a predicted strong particle burst during gravitational collapse, showing that it occurs not only in idealized models but also in more realistic matter-filled collapse scenarios.

Contribution

It demonstrates that the double burst phenomenon of particle creation is a robust feature across different models of gravitational collapse, including matter-filled interiors.

Findings

Double burst phenomenon occurs in matter-filled collapse models

The burst is a robust feature independent of the specific collapse model

Particle creation spectrum changes drastically near the end of collapse

Abstract

Hawking has predicted that the formation of a black hole by gravitational collapse causes quantum particle creation and the spectrum of the particles is almost thermal. This phenomenon is called the Hawking radiation. Recently, it has been predicted that the particle creation may drastically change from the Hawking radiation to a strong double burst if the gravitational collapse suddenly stops just before the formation of the event horizon. By contrast with the Hawking radiation, the burst may be so strong that it can be of observational interest even for collapsing objects with astrophysical mass scales. However, the burst phenomenon has been predicted through the studies of idealized models in which a spherical hollow shell begins to collapse, but stops shrinking and eventually settles down to a static "star". Therefore, one might guess that it could be particular to the hollow shell model. In this paper, we study the particle creation due to the gravitational collapse of a spherical object whose interior is filled with matter. In this model, we obtain similar results to those in the case of the hollow shell model. This implies that the double burst is a robust property of particle creation by the sudden braking of gravitational collapse.