Speaker
Doris Arzoumanian
(IAS Orsay)
Description
Herschel dust continuum images have revealed the ubiquity of filaments in the interstellar medium (ISM) and their fundamental role in the star formation process. Planck dust polarization observations trace the magnetic field structure of the ISM.
Filamentary structures are formed by the interplay of interstellar turbulence, gravity and magnetic field. What is the role of these various processes in the formation and evolution of interstellar filaments?
One of the surprising result obtained from the analysis of the filament radial profiles observed with Herschel is the narrow distribution of their inner widths (~0.1 pc) regardless of their central column density and environment. This characteristic filament width is close to the sonic scale around which the transition between supersonic and subsonic turbulent motions occurs in the cold ISM. This result put forward the role of interstellar turbulence in forming the filaments.
Follow-up molecular line observations with the IRAM 30m telescope, have shown an increase in the non-thermal velocity dispersion of the densest filaments as a function of their central column density suggesting the role of gravity in the evolution of the dense self gravitating filaments which grow in mass by accretion of background material while fragmenting into prestellar cores.
The role of magnetic field in the formation and evolution of filaments is still debated. In order to investigate this issue, I will present how we model the 3D field structure and the polarization properties of interstellar filaments and their background clouds to interpret Planck observations of the polarized dust emission.
Author
Doris Arzoumanian
(IAS Orsay)