Protostars and Planets VI, Heidelberg, July 15-20, 2013

Poster 1B016

Large and small-scale magnetic fields in star-forming regions

Reissl, Stefan (University of Kiel)
Bertrang, Gesa (University of Kiel)
Wolf, Sebastian (University of Kiel)
Banerjee, Robi (Hamburg Observatory)
Das, Himadri Sekhar (Assam University)
Seifried, Daniel (Hamburg Observatory)
Körtgen, Bastian (Hamburg Observatory)

We present numerical and observational studies aimed at analyzing the potential of multi-wavelength high-spatial resolution continuum polarization measurements for constraining the multi-scale structure of magnetic fields in the interior and environment of molecular clouds. Numerical simulations: We developed an extended, adaptive grid version of the 3D Monte-Carlo radiation transfer code MC3D (Wolf et al., 1999, 2003) for multi-wavelength polarization simulations. On the basis of theoretical dust grain models, polarization due to dichroic extinction and reemission as well as scattering is considered. Multi-scale magneto-hydrodynamical (MHD) simulations of the interstellar medium (ISM) provide the complex distributions of the density, temperature, and magnetic field in star-forming regions. This type of sophisticated synthetic polarization modeling will allow us to prepare and properly analyze existing and future observations of the three-dimensional magnetic field structure in the ISM. Various kinds of dust grain properties and advanced MHD scenarios are considered to cover the broad variety of observable ISM characteristics. Observations: Bok globules represent an ideal environment to study the influence of magnetic fields on the process of low-mass star formation. The magnetic field strength and structure in the dense inner regions of the globules can be determined by observing the polarized reemission radiation of aligned dust grains in the sub-mm wavelength range. The magnetic field in the outer, less dense parts of the globules can be traced by observing polarized radiation of background stars in the optical or near-IR. We present polarimetric observations of two Bok globules, CB68 and B335, carried out in the near-IR (ISAAC/VLT) and in the optical (IFOSC/IGO). Together with archival sub-mm data (SCUBA/JCMT), we trace the magnetic fields in these objects from 10^3 AU scales up to 10^5-10^6 scales for the first time.

Click here to view poster PDF