1203.3677 (N. V. Voshchinnikov et al.)

Interstellar polarization and grain alignment: the role of iron and silicon    [PDF]

N. V. Voshchinnikov, Th. Henning, M. S. Prokopjeva, H. K. Das

We compiled the polarimetric data for a sample of lines of sight with known abundances of Mg, Si, and Fe. We correlated the degree of interstellar polarization $P$ and polarization efficiency (the ratio of $P$ to the colour excess $E(B-V)$ or extinction $A_V$) with dust phase abundances. We detect an anticorrelation between $P$ and the dust phase abundance of iron in non silicate - containing grains $< [\rm Fe(rest)/H > ]_\rm d$, a correlation between $P$ and the abundance of Si, and no correlation between $P/E(B-V)$ or $P/A_V$ and dust phase abundances. These findings can be explained if mainly the silicate grains aligned by the radiative mechanism are responsible for the observed interstellar linear polarization.

View original: http://arxiv.org/abs/1203.3677