Circular orbits and polarized images of charged particles orbiting a Kerr black hole with a weak magnetic field
Tsaichen Lee, Zezhou Hu, Minyong Guo, Bin Chen
Abstract
In this work, we study the circular motions of charged particles and their polarized images around the Kerr black hole immersed in a weak magnetic field. We pay special attention to the case where the magnetic field and the charge-to-mass ratio are insignificant. Thus, the effective potential along the radial motion reduces to a cubic form approximately so that we can express the radius of the innermost stable circular orbit analytically in terms of the energy and angular momentum of charged particles. Moreover, we computed the polarized radiation of these particles and obtained the polarized images semianalytically for different spins, observational angles, and prograde and retrograde orbits. In particular, we find that these parameters significantly impact the polarization rotation and the magnitude of the polarization flux.