G objects as Primordial Black Hole-Neutron Star Remnants: Population Modeling and Multi-Wavelength Observables

TL;DR

This paper proposes that G objects near the Galactic Center are remnants of neutron stars converted into black holes by primordial black holes, offering a new way to probe dark matter and compact-object physics.

Contribution

It introduces a population model linking G objects to dark matter and primordial black holes, and identifies observable signatures to test this hypothesis.

Findings

G objects can be explained as neutron star remnants converted by primordial black holes.

The model accounts for the G objects' stability and infrared properties.

Multiple observational channels can distinguish this scenario from stellar models.

Abstract

The nature of the so-called G objects orbiting the Galactic Center remains unresolved. These sources exhibit compact Br$\gamma$ emission, extreme infrared colors, and remarkable dynamical stability through close passages to the central supermassive black hole, challenging conventional interpretations as stars or unbound gas clouds. We investigate the hypothesis that G objects are the remnants of neutron stars that have been converted into low-mass black holes through the capture of primordial black holes, a viable dark-matter candidate. We construct a population-level framework linking the abundance and spatial distribution of these remnants to the neutron-star population, the inner dark-matter density profile, and the primordial black-hole mass and abundance. Within this framework, the observed G-object population and the long-standing deficit of ordinary radio pulsars in the Galactic Center emerge as complementary consequences of the same conversion process. We further identify a suite of observational signatures-across infrared, radio, X-ray, and microlensing channels-that render this scenario empirically testable and distinguishable from stellar-envelope models. Our results show that G objects can act as sensitive probes of compact-object capture physics and of dark matter on sub-galactic scales.