EPoS Contribution
EPoS Contribution
An ordered magnetic field in a turbulent cloud

Georgia Panopoulou
UoC, Heraklion, GR
The role of the magnetic field in the various stages and environments of star formation is hotly debated. While the large-scale magnetic field has been mapped in many star-forming clouds, little is known about the field in quiescent molecular clouds. We used the RoboPol optical polarimeter to trace the plane-of-the-sky orientation of the magnetic field in the Polaris Flare, a translucent high-latitude molecular cloud. Our map covers over 10 square degrees, and includes 609 reliable measurements. The projected magnetic field shows a large-scale smoothly varying pattern across a large part of the cloud. We compare the orientations of the filamentary structures found in the Herschel dust emission image with the polarization angles in our data. More than 70% of plane-of-sky magnetic field orientations are consistent with those of the gas structures. We also compare the structures found in dust emission with those seen in reflection in optical wavelengths. We find correlations between the dispersion of polarization angles, the fractional linear polarization and the relative orientations of gas and field. We estimate the plane-of-sky magnetic field strength in regions of the cloud and discuss implications on cloud geometry and stability.
Caption: Left: Herschel 250-micron map of the Polaris Flare (grayscale) with optical polarization data overplotted in red. Right: Visualization of cloud filamentary structure that serves to compare filament and polarization orientations.
K. Tassis, UoC/IESL, GR
I. Psaradaki, UoC, GR
Key publication

Suggested Session: Magnetic Fields