Submillimeter Polarimetry with PolKa, a reflection-type modulator for the APEX telescope

Understand

Imaging polarimetry is an important tool for the study of cosmic magnetic fields.

• In our Galaxy, polarization levels of a few up to $\sim$10\% are measured in the submillimeter dust emission from molecular clouds and in the synchrotron emission from supernova remnants.
• Only few techniques exist to image the distribution of polarization angles, as a means of tracing the plane-of-sky projection of the magnetic field orientation.
• At submillimeter wavelengths, polarization is either measured as the differential total power of polarization-sensitive bolometer elements, or by modulating the polarization of the signal.