Particle-like ultracompact objects in Einstein-scalar-Gauss-Bonnet theories

TL;DR

This paper introduces a new class of ultracompact, particle-like objects in Einstein-scalar-Gauss-Bonnet theories that exhibit lightrings and gravitational-wave echoes, expanding the landscape of possible compact objects.

Contribution

It presents globally regular, particle-like solutions with diverging scalar fields but well-behaved stress-energy tensors, and compares them with other known compact objects.

Findings

Existence of particle-like ultracompact solutions in Einstein-scalar-Gauss-Bonnet theories.

These objects feature lightrings and gravitational-wave echoes.

The scalar field diverges at the center but remains physically consistent.

Abstract

We present a new type of ultracompact objects, featuring lightrings and echoes in the gravitational-wave spectrum. These particle-like solutions arise in Einstein-scalar-Gauss-Bonnet theories in four spacetime dimensions, representing globally regular spacetime manifolds. The scalar field diverges at the center, but the effective stress-energy tensor is free from pathologies. We determine their domain of existence and compare with wormhole solutions, black holes and the Fisher solution.