Description
The composition of black hole jets—whether lepton-dominated or baryon-loaded—remains a longstanding open question, primarily due to the spectral degeneracy observed in high-energy emissions. We propose that extreme mass ratio (EMR) black hole binaries, particularly systems involving a secondary microquasar interacting periodically with the accretion flow of a primary supermassive black hole, can serve as natural laboratories for disentangling jet composition. In such systems, periodic jet–accretion collisions can give rise to distinct emission signatures shaped by underlying leptonic or hadronic processes. By modeling how these periodic features vary with jet composition, we identify multi-frequency observables that can help break the leptonic–baryonic degeneracy. These electromagnetic signatures offer a complementary probe to the emerging multi-messenger approaches for uncovering the nature of relativistic jets.
