Speaker
Gesa Bertrang
(ITAP, University of Kiel)
Description
The influence of magnetic fields on the star-forming process is still under debate. A very good environment to study this influence is given in low-mass star-forming regions, so-called Bok globules. These objects are less affected by other processes, such as large-scale turbulences. The magnetic field strength and structure in the dense inner regions of these 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-infrared. Thus, multi-wavelength observations reveal the magnetic field strength and structure on various scales across the entire globule.
I will present the results of our imaging polarimetry study on Bok globules for which we carried out new polarimetric observations of the three globules CB68, B335 and CB54 in the near-infrared (with ISAAC/VLT and SOFI/NTT) and in the optical wavelength range (with IFOSC/IGO). The first part of our study, represented by CB68 and B335, is focused on ideal, very regularly shaped globules while in the second part globules with more complex morphologies are considered: CB54 shows strong long-scale turbulences but nevertheless, observations in the optical show ordered magnetic field lines in the outer, less dense parts of this globule. Together with archival sub-mm data (obtained with SCUBA/JCMT), we trace the magnetic fields in these objects on scales from 10'000 AU to 100'000 AU for the first time
Author
Gesa Bertrang
(ITAP, University of Kiel)