Magnetic Fields in Gas Flows near the Galactic Center

Polarization of molecular lines at 1.3 mm wavelength has been used to trace magnetic field directions between 1 and 3 pc north of Sgr A*. This region connects the Galactic center and the circumnuclear disk (CND) and contains the northern arm of the ionized minispiral. Previous observations using polarized thermal dust emission have shown a rather uniform north-south magnetic field but with uncertainty about the relative contributions (and confusion) of the rotating disk and infalling streamers. By separating these components by velocity in carbon monoxide (CO) spectra, we find that the -20 km s(-1) streamer has a different magnetic field from that of the CND, and there is no clear correlation with gas flow directions. However, the dust data do trace the CND magnetic field direction within a few degrees. The CO polarization levels demonstrate the theoretically expected variations with line optical depth.