The Polarizing Power of the Interstellar Medium in Taurus
H. G. Arce, A. A. Goodman, P. Bastien, N. Manset, M. Sumner;
ApJ, 1998, 499, L93
ABSTRACT:We present a study of the polarizing power of dust in cold dense regions (dark clouds) compared with that of dust in the general interstellar medium
(ISM).
Our study uses new polarimetric, optical, and spectral classification
data for 36 stars to carefully study the relation between polarization
percentage (p) and extinction ( A_{V} ) in the Taurus dark cloud complex.
We find
two trends in our p-A_{V} study: (1) stars that are background to the warm
ISM show an increase in p with A_{V} , and (2) the percentage of polarization
of stars that are background to cold dark clouds does not increase with
extinction.
We detect a break in the p-A_{V} relation at an extinction of 1.3+/-0.2
mag, which we expect corresponds to a set of conditions where the polarizing
power of the dust associated with the Taurus dark clouds drops
precipitously.
This break point places important restrictions on the use of polarimetry in
studying interstellar magnetic fields.
KEYWORDS: ism: dust, extinction, ism: clouds, ism: magnetic fields, polarization
PERSOKEY:polarisation, MAGNETIC FIELD, EXTINCTION, OPTICAL, ,
CODE: arce98