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Session 66 - Astrophysical Diagnostics from Polarimetry.
Oral session, Wednesday, June 12
Playcircle,
Starlight, which passes through clouds of interstellar dust grains aligned to the Galactic magnetic field or which scatters off dust grains in reflection nebulae, becomes polarized. The nature of this polarization places important constraints on shape, size and composition of the interstellar dust. Polarimetric observations have now been made at ultraviolet, visible and infrared wavelengths for many lines of sight within the Galaxy.
Modeling efforts combine the constraints provided by polarimetric observations with other constraints such as extinction behavior and elemental abundances in the interstellar medium. Modeling of separate populations of silicate and graphite grains is giving way to modeling of more realistic composite grains which includes the effects of porosity on electromagnetic scattering, real inclusions (silicate, graphite, superparamagnetic etc.), and alignment. New numerical techniques such as the Discrete-Dipole Approximation (DDA) are being used.
