Grain alignment in the taurus dark cloud

Academic Article

Abstract

  • Variations in the polarization efficiency (p/A) of interstellar grains as a function of environment place vital constraints on models for the mechanism of alignment. In this Letter, polarimetric observations of background field stars are used to investigate alignment in the Taurus Dark Cloud for extinctions in the magnitude range 0 < Ak < 2.5 (0 < AV < 25). Results show a strong systematic trend in polarization efficiency with extinction, well represented by a power law p/A f A-056. A number of possible interpretations of this result are discussed. Assuming magnetic alignment of the grains, the observed trend may be influenced by such factors as small-scale magnetic field structure, variation of magnetic field strength and coupling of gas and dust temperatures as functions of density, and systematic changes in the efficiency of suprathermal spin as a function of grain surface properties and H/H2 fraction within the dark cloud. © 1995 The American Astronomical Society.
  • Authors

    Digital Object Identifier (doi)

    Author List

  • Gerakines PA; Whittet DCB; Lazarian A
  • Start Page

  • L171
  • End Page

  • L175
  • Volume

  • 455
  • Issue

  • 2