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SÉMINAIRE DU LERMA
OBSERVATOIRE DE PARIS
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Vendredi 27 juin 2003, a 14h


77 avenue Denfert Rochereau, Paris 14



Salle de l'Atelier, Observatoire de Paris





Magnetic Fields through Polarimetry: Progress on Grain Alignment Theory



Alex Lazarian

University of Wisconsin



Résumé : ISM is magnetized with magnetic field influencing almost all of its properties. One of the most informative techniques to study magnetic is based on the use of starlight polarization and polarized emission arising from aligned dust. Grain alignment theory addresses the issue of how reliable the interpretation of the polarization maps in terms of magnetic fields is. Although grain alignment is a problem of half a century standing, recent progress achieved in the field makes me believe that we are close to solving this mistery. I review basic physical processes involved in grain alignment and discuss the niches for different alignment mechanisms. I show that the some of textbook mechanims are not so promissing, while the radiative torque mechanism ignored for more than 20 years after its introduction looks most attractive.