Infrared polarimetry and the interstellar magnetic field

Abstract

A good correlation between interstellar polarization and interstellar extinction is found at 2.2 microns for almost all lines of sight. This correlation has a slope less than unity, holds true over a range in optical depth of a factor of 100, and is independent of the physical path length. A model involving equal contributions from a uniform component and a random component to the interstellar magnetic field fits the data well. These results imply that the two components of the interstellar magnetic field maintain roughly the same proportions and strength in most phases of the ISM.