Work

Grain Alignment by Radiation in Dark Clouds and Cores

Year: 2005

Type: article

Abstract: We study alignment of grains by radiative torques. We found a steep rise in radiative torque efficiency as grain size increases. This allows the larger grains that are known to exist within molecular clouds to be aligned by the attenuated and reddened interstellar radiation field. In particular, we found that, even deep inside giant molecular clouds, e.g., at optical depths corresponding to A V ≲ 10, large grains can still be aligned by radiative torques. This means that, contrary to earlier claims, far-infrared/submillimeter polarimetry provides a reliable tool to study magnetic fields of prestellar cores. Our results show that the grain size distribution is important for determining the relation between the degree of polarization and intensity.

Source: The Astrophysical Journal

DOI: 10.1086/432528

Authors: Jungyeon Cho, A. Lazarian

Institutions: Chungnam National University, University of Wisconsin–Madison

Language: English

Topic: Astrophysics and Star Formation Studies

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: bronze

Funders: National Science Foundation, Canadian Institute for Theoretical Astrophysics

Award: Diffraction-limited Polarimetry at the Caltech Submillimeter Observatory