Infrared polarimetry of Bok globules

Near-infrared photometry and polarimetry and optical polarimetry of field stars shining through the Bok globules B118, B133, and B361 are presented. Three distinct density distributions are found and mass estimates of the inner regions of these globules are given. The polarization vectors show no indication that the magnetic field is being compressed due to gravitational collapse in the globules. The polarization vectors are bent in the southwestern corner of B361 and are consistent with a collision between the globule and the intercloud medium in this region. The presence of aligned grains in the isolated and cold environments of these globules demands an efficient grain alignment mechanism. No dependence of polarization efficiency P_K/E(J - K) on temperature, density, and magnetic field strength (inferred from regions of different optical depth) is found. Polarization efficiency does appear to be lower in regions with more random position angles.