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11th of July 2018
ATNF Colloquium
Polarization Archetypes in Protostellar Disks and Cores: The ALMA view and beyond (SKA)
by Josep Miquel Girart (Institut de Ciències de l'Espai)
Abstract: Linear polarization observations with ALMA is allowing to study the dust polarization properties at disk and core scales towards low and high mass star forming regions with a superb sensitivity. At core scales, the dust polarization is a good tracer of the magnetic fields threading the cores. Therefore, ALMA observations allow to investigate the role of magnetic fields in the formation of stars. On the other hand, and contrary to what it was though few years ago, the dust polarized emission in protostellar disks is not only produced by dust grains aligned with the magnetic fields. Self-scattering and radiation alignment of non-spherical grains can contribute significantly to the polarized emission. In this presentation I will show different targets where the different mechanism are revealed and what we can learn from them. I will also talk about how SKA can help in the study of planet forming disks through dust polarization observations.

The figure above is a composite of the 1.14 mm continuum ALMA Stokes I (contours), polarization fraction (colour scale) and polarization position angle segments (black bars) in the GGD27 MM1 disk, associated with a 25-35 M_sun young stellar object. The contour levels are 3, 10, 50, 120, 200 and 400 K. The wedge shows the scale of the polarized intensity and of polarization fraction. The synthesized beam is shown in the bottom right corner of the panels. (From Girart et al. 2018, ApJL)

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