Observatoire de Paris Institut national de recherche scientifique français Univerité Pierre et Marie Curie Université Paris Diderot - Paris 7

Polarisation and High Angular Resolution - Radiative transfer, magnetic fields, AGN and more

lundi 22 février 2021, par Lucas Grosset (SOFIA - USRA - NASA Ames Research Center)

Jeudi 25 février 2021 à 16h00 , Lieu : En visioconférence

From visible to far-infrared, polarisation has proven helpful in bringing the extra constraints needed to improve our understanding of some complex astrophysical objects. This was especially true in the active galactic nuclei (AGN) field where polarisation was the corner stone in the development of the unified model for AGNs. Indeed, polarisation bring new observable to classical imaging or spectroscopy, setting stronger constraints on the physical mechanisms occurring at the observed location, but it also allows to get rid of some contrast issues. Furthermore, just like classical imaging, polarisation benefits a lot from high angular resolution that can separates two regions with very different polarisation, previously combined into a low resolution with a different polarisation (usually, polarisation degree increase with better resolution).

I will present two AGNs where the combination of polarisation and high angular resolution, in the near-infrared and in the far-infrared, helped to investigate the dust distribution surrounding the central engine of the AGN and the organization of magnetic field at larger scale. I will present both the observations and the numerical methods used to investigates these polarimetric observations, including the radiative transfer code MontAGN.

Pour assister au séminaire, contacter johan.mazoyer obspm.fr