High-energy cosmic ray production in X-ray binary jets

As smaller analogues of active galactic nuclei, X-ray binaries (XRBs)are also capable of launching jets that accelerate particles to high energies. In this work, we re-examine XRB jets as potential sources of high-energy cosmic rays (CRs) and explore whether they could provide a significant second Galactic component to the CR spectrum. In the most intriguing scenario, XRB-CRs could dominate the observed spectrum above the so-called knee feature at ∼3 × 10¹⁵ eV, offering an explanation for several key issues in this transition zone from Galactic to extragalactic CRs. We discuss how such a scenario could be probed in the near future via multi messenger observations of XRB jets, as well as diffuse Galactic neutrino flux measurements.