POLARIZED RADIATION FROM MAGNETIC ACCRETION RINGS

Calculations of the polarized radiation from extended magnetic polar caps have been previously presented by us, and fits to the observations of the intermediate polar BG CMi have been given recently by Chanmugam et al., with a polar field of ∼4 MG. Motivated by suggestions that the emission region may instead be ringlike, we study the polarized radiation emitted from such a region, in general, and we explain some of its gross features in terms of its geometry and magnetic field. We also show that the emission from a ring shows greater variation with viewing angle compared to that from a polar cap. The results are also applied to BG CMi.