Radio astronomical polarimetry and the Lorentz group

In radio astronomy, the polarimetric properties of radiation are often modi fied during propagation and reception. Effects such as Faraday rotation, re ceiver cross talk, and differential amplification act to change the state o f polarized radiation. A general description of such transformations is use ful for the investigation of these effects and for the interpretation and c alibration of polarimetric observations. Such a description is provided by the Lorentz group, which is intimately related to the transformation proper ties of polarized radiation. In this paper, the transformations that common ly arise in radio astronomy are analyzed in the context of this group. This analysis is then used to construct a model for the propagation and recepti on of radio waves. The implications of this model for radio astronomical po larimetry are discussed.