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Título
:
Grain Alignment in ISM and circumstellar regions
Conferencista:
Alex Lazarian, Univ. Wisconsin - Madison
Data
:
Segunda-Feira, 19/02/01 15H 30M
Local
:
Auditório L.B.F. Clauzet - Água Funda
Sumário
:
Aligned grains provide one of the easiest ways to study magnetic
fields in diffuse gas and molecular clouds. How reliable our conclusions
about the inferred magnetic field depends critically on our understanding of
the physics of grain alignment. Although grain alignment is a problem of half
a century standing recent progress achieved in the field makes us believe that
we are approaching the solution of this mystery. I review basic physical
processes involved in grain alignment and show why mechanisms that were
favored for decades do not look so promising right now. I also discuss why the
radiative torque mechanism ignored for more than 20 years looks right now
the most powerful means of grain alignment. I shall briefly discuss
how to use polarimetry to study circumstellar magnetic fields.