Star polarization in the Galactic plane

Polarimetric observations were obtained with the Mimir instrument on the Perkins Telescope in Flagstaff, AZ, along a line of constant Galactic longitude ({ell}=150{deg}) with 17 pointings of the 10'x10' field of view between -75{deg}<b<10{deg}, with more frequent pointings toward the Galactic midplane.

A total of 10962 stars were photometrically measured and 1116 had usable polarizations. The observed distribution of polarization position angles with Galactic latitude and the cumulative distribution function of the measured polarizations are compared to predicted values. While the predictions lack the effects of turbulence and are therefore idealized, this comparison allows significant rejection of A0-type magnetic field models.