Speaker
Description
Black hole binaries are observed from radio to gamma rays. While it is believed that the radio and X-ray emission comes from relativistic jets and accretion flows, respectively, the origin of the gamma-ray emission is still under debate. When a black hole binary is in the hard state, it likely has a magnetically arrested disk (MAD), where the magnetic flux threading the black hole is in a saturation level. We consider a scenario where the multi-wavelength emission of a binary comes from the jets and MAD. We apply such a two-zone model to the well measured Galactic binary Cygnus X-1. In our model, electrons and protons in the MAD are heated and accelerated by the turbulence, while electrons in the jet are accelerated by magnetic reconnection. Thermal electrons in the accretion flows produce X-ray emission by up-scattering photons from the standard disk. Nonthermal electrons in the jets produce radio and gamma-ray emission through synchrotron radiation and synchrotron self-Compton processes, respectively. Protons accelerated in the MAD emit very-high-energy gamma-rays and neutrinos through hadronuclear interaction and photomeson production. We demonstrate that the model may explain the multi-wavelength emission and predict that the TeV gamma-ray and neutrino emission of Cygnus X-1 may be observed by future experiments.
