New Manifestations of The Strong, Bi-directional Magnetic Field at the Galactic Center

Non-thermal radio filaments unique to the Galactic center region were first discovered over 40 years ago, and observations over the years have increasingly shown that there is a literal “forest” of such magnetic filaments oriented largely perpendicular to the Galactic plane, many of them arrayed in compact “bundles”. They indicate that the magnetic field in the intercloud medium is pervasive and poloidal. On the other hand, probes of the magnetic field within massive clouds of the central molecular zone, mostly by observations of polarized, thermal dust emission, show that the field is mostly parallel to the Galactic plane within clouds. This dichotomy has recently been emphasized by the results of a large-scale survey carried out in the far-infrared with the HAWC+ imaging polarimeter on SOFIA. Both field systems were evidenced. This talk will present those results and critically examine the hypotheses that have been offered for the origin of the two systems. On finer scales, HAWC+ observations at 53 µm of the prominent HII region surrounding the massive Quintuplet star cluster offer an impressively striking contrast between what happens when the winds and radiation from the cluster strike the HII region interface at orientations that are parallel and perpendicular to the local magnetic field.