Dynamical Formation of Scalarized Black Holes and Neutron Stars through Stellar Core Collapse

TL;DR

This paper demonstrates that in scalar-Gauss-Bonnet gravity, realistic stellar core collapse can produce scalarized black holes and neutron stars, providing a physical formation mechanism for these objects beyond previous theoretical studies.

Contribution

First to study fully nonlinear stellar core collapse leading to scalarized compact objects in scalar-Gauss-Bonnet theories, revealing realistic formation pathways.

Findings

Core collapse can produce scalarized black holes and neutron stars.

Multiple pathways lead to scalarized or non-scalarized end states.

Potential observational signatures of scalarization phenomena.

Abstract

In a certain class of scalar-Gauss-Bonnet gravity, the black holes and the neutron stars can undergo spontaneous scalarization -- a strong gravity phase transition triggered by a tachyonic instability due to the nonminimal coupling between the scalar field and the spacetime curvature. Studies of this phenomenon have, so far, been restricted mainly to the study of the tachyonic instability and stationary scalarized black holes and neutron stars. To date, no realistic physical mechanism for the formation of isolated scalarized black holes and neutron stars has been proposed. We study, for the first time, the spherically symmetric fully nonlinear stellar core collapse to a black hole and a neutron star in scalar-Gauss-Bonnet theories allowing for a spontaneous scalarization. We show that the core collapse can produce scalarized black holes and scalarized neutron stars starting with a nonscalarized progenitor star. The possible paths to reach the end (non)scalarized state are quite rich leading to interesting possibilities for observational manifestations.