HERTZ, A SUBMILLIMETER POLARIMETER

We describe a 32 pixel polarimeter, Hertz, for use at the Caltech Subm illimeter Observatory. We present polarization maps of the Orion molec ular cloud (OMC-1) at 350 mu m (46 detections) and 450 mu m (19 detect ions) with 3 sigma or better statistical significance. The 350 mu m po larization ranges from 1.4% to 6.8% with a median value of 3.3%. The p osition angles are fairly uniform across the source at an angle of sim ilar to 30 degrees (east of north). We describe the design and perform ance characteristics of the polarimeter and discuss systematic effects due to telescope and instrumental polarization, atmospheric fluctuati ons, and reference beam flux.