Dust grain alignment in IC 63 - H2 formation enhancement and collisional disalignment

Andersson, B.-G.; Vaillancourt, John E.; Acosta-Pulido, J. A.; Fernandez, Manuel
Bibliographical reference

American Astronomical Society, AAS Meeting #227, id.#424.05

Advertised on:
1
2016
Number of authors
4
IAC number of authors
1
Citations
0
Refereed citations
0
Description
Interstellar dust grain alignment gives rise to polarization from UV to mm wavelengths, allowing the study of the geometry and strength of the magnetic field. Over the last couple of decades observations and theory have led to the establishment of the Radiative Alignment Torque (RAT) mechanism as the leading candidate to explain the effect. With a quantitatively well constrained theory, polarization can be used not only to study the interstellar magnetic field, but also the dust and other environmental parameters. Photo-dissociation Regions (PDRs), with their intense, anisotropic radiation fields, consequent rapid H2 formation, and high spatial density-contrast provide a rich environment for such studies. Here we discuss an expanded optical, NIR and mm-wave study (cf. Andersson et al. 2013) of the IC 63 reflection nebula, showing strong H2 formation-enhanced alignment and the first direct, empirical, evidence for disalignment due to gas-grain collisions.