Polarizing properties of grazing-incidence x-ray mirrors: comment

Abstract

We show that grazing-incidence telescopes, like those used for x-ray imaging, present negligible instrumental polarization. This property does not depend on the number of reflections the telescope employs to lead light from the entrance pupil to the focal plane. The result applies to the various mirrors of the advanced x-ray astrophysics facility satellite. In this particular case we have quantified the residual instrumental polarization to be between 10(-3) and 5 × 10(-5), depending on the size of the resolution elements.