General relativistic magnetohydrodynamic simulations of accretion onto exotic compact objects

TL;DR

This paper reviews the current state of general relativistic magnetohydrodynamic simulations of accretion processes onto exotic compact objects, highlighting their importance for observational detection and future research directions.

Contribution

It provides a comprehensive overview of existing GRMHD simulation studies involving exotic compact objects and discusses potential future research pathways.

Findings

Summarizes various simulation approaches for ECOs

Identifies key observational signatures of accretion onto ECOs

Highlights gaps and future directions in the field

Abstract

Some of the extensions to general relativity and to the Standard Model of particle physics predict families of hypothetical compact objects, collectively known as exotic compact objects (ECOs). This category can be defined to encompass non-Kerr black holes both within and beyond general relativity, as well as horizonless compact objects such as boson stars. In order to model observational signatures and identify possible detections, it is crucial to understand the interaction between these objects and their surrounding medium, usually plasmas described by the equations of general relativistic magnetohydrodynamics (GRMHD). To this end, we review the existent literature on GRMHD simulations of accretion onto these objects. These cover a variety of objects and accretion patterns. We conclude by listing possible directions to continue exploring this relatively young field.