Probing Jet Compositions with Extreme Mass Ratio Binary Black Holes

TL;DR

This paper proposes using emissions from extreme mass ratio binary black holes to determine whether their jets are leptonic or baryonic, providing a new observational method to understand jet composition.

Contribution

It introduces a novel approach to probe jet composition using the episodic emissions from miniquasars in EMRB systems, linking jet signatures to their particle content.

Findings

Baryonic jets produce stronger gamma-ray emissions than leptonic jets.

Gamma-ray-to-UV emission ratios can distinguish jet compositions.

Modeling suggests electromagnetic signals combined with multi-messenger data can constrain jet physics.

Abstract

Determining whether black hole jets are dominated by leptonic or baryonic matter remains an open question in high-energy astrophysics. We propose that extreme mass ratio binary (EMRB) black holes, where an intermediate mass secondary black hole (a "miniquasar") periodically interacts with the accretion flow of a supermassive black hole (SMBH), offer a natural laboratory to probe jet composition. In an EMRB, the miniquasar jet is launched episodically after each disk-crossing event, triggered by the onset of super-Eddington accretion. The resulting emissions exhibit temporal evolution as the jet interacts with the SMBH accretion disk. Depending on whether the jet is leptonic or hadronic in composition, the radiative signatures differ substantially. Notably, a baryonic jet produces a more pronounced gamma-ray output than a purely leptonic jet. By modeling the evolution of the multifrequency characteristic features, it is suggested that the gamma-ray-to-UV emissions may serve as a diagnostic tool capable of distinguishing between leptonic and baryonic scenarios. The resulting electromagnetic signals, when combined with multi-messenger observations, offer a powerful means to constrain the physical nature of relativistic jets from black holes.