Polarimetric observations of the quasar 3C-345

Abstract

Infrared and optical polarimetric observations of the quasar 3C 345 are presented, which show a decrease in the degree of polarization with frequency previously observed by Smith et al., and interpreted by them as the result of dilution of the polarized flux by a non-polarized thermal component (the "blue bump"). The new data are compared to previous fits of this model to 3C 345, and the validity of the model is discussed.