2018ApJ...862..150H

Utilizing James Clark Maxwell Telescope 850 µm SCUPOL dust polarization data, we investigate the configuration of the magnetic (B) field in the circumnuclear disk (CND) of the Galactic center. The SCUPOL data show a highly improved polarization coverage and resolution compared with earlier 100 µm observations. The 850 µm data have a resolution and coverage similar to previous 350 µm polarimetry data. However, with a proper sampling on a 10'' grid, we find that the 850 µm data trace the morphological structures of the CND substantially better. Furthermore, because the 850 µm trace the field deeper into the material near SgrA*, they represent the highest-resolution submillimeter probe to date of the CND magnetic field. The observed B-field morphology is well described by a self-similar axisymmetric disk model where the radial infall velocity is one-quarter of the rotational velocity. A detailed comparison with higher-resolution interferometric maps from the Submillimeter Array further reveals that the B-field aligns with the neutral gas streamers connecting to the CND. Moreover, the innermost observed B-field structure also appears to trace and align with the mini-spiral located inside the CND. This suggests that there is one underlying B-field structure that is connecting the CND with its streamers and the inner mini-spiral. An estimate of β_Plasma <= 1-based on the global B-field morphology that constrains the azimuthal-to-vertical field strength ratio of around 40 combined with a measurement of the azimuthal velocity indicates that the B-field appears dynamically significant toward the CND and also onwards to the inner mini-spiral.