協辦單位
NQU
協辦單位
Kinmen/edu
協辦單位
ASIAA
贊助單位
MOST
會徽Logo
名稱Title
2018天文年會
國立金門大學
5月18日至20日

論文摘要

The Role of the Magnetic Field in the Circumnuclear Disk of the Galactic Center - Implications From 850 micron Polarization Data

[ Oral ]

Pei-Ying Hsieh (ASIAA); Patrick M. Koch (ASIAA); Woong-Tae Kim (SNU); Paul T. Ho (ASIAA); Ya-Wen Tang (ASIAA); Hsiang-Hsu Wang (CUHK)

Utilizing James Clark Maxwell Telescope (JCMT) 850 micron SCUPOL dust polarization data, we investigate the configuration of the magnetic ($B$-) field in the circumnuclear disk (CND) of the Galactic Center (GC). Overall on a large scale, the $B$-field shows a clear predominantly toroidal morphology. Compared to earlier 100 micron and 350 micron observations, the SCUPOL data show a hugely improved polarization coverage at a higher resolution. In general, 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 (SMA) further reveals that the $B$-field aligns with the neutral gas streamers where they are connecting to the CND. Moreover, the innermost observed $B$-field structure also appears to trace and align with the ionized mini-spirals located inside the CND. This suggests that there might be one underlying $B$-field structure that is connecting the CND with its streamers and the inner mini-spirals. An estimate of beta plasma parameter ~1 -- based on the global B-field morphology that constrains the azimuthal-to-vertical field strength ratio to be around 40 combined with a measurement of the azimuthal velocity -- indicates that the B-field appears dynamically significant towards the CND and also onwards to the inner mini-spirals.