Submillimeter polarimetric observations of the Galactic center

We report the first detection of polarized submillimeter emission from the Sagittarius A region at the Galactic center. We observed three separate 2' x 2' fields: one centered on the circumnuclear disk, one centered on the pe ak of the molecular cloud M-0.02-0.07 (also called the "50 km s(-1) cloud") , and one centered on the peak of the molecular cloud M-0.13-0.08 (also cal led the "20 km s(-1) cloud"). Linear polarization at lambda = 350 mu m was detected in each of the three regions, at a total of 106 distinct sky posit ions. In the circumnuclear disk, the projected magnetic field directions th at we infer from our measurements are similar to those inferred from previo us far-infrared (lambda = 100 mu m) polarimetry. In the "curved ridge" regi on of M-0.02-0.07 that has been compressed by the expansion of Sgr A East, our results show clearly the effects of this compression on the magnetic fi eld. In M-0.13-0.08, we observe what appears to be a stretched magnetic hel d, as expected for this tidally sheared cloud. It has been suggested that a " finger-like extension " or " streamer " from M - 0.13 - 0.08 is falling into the circumnuclear disk. We tentatively interpret a flaring of magnetic held lines that we see in M-0.13-0.08 as evidence that the entire cloud ha s a velocity component in the Galactic eastern direction, i.e., toward the circumnuclear disk. Further observations are needed to test this interpreta tion. We argue that polarimetry of dust emission provides a promising tool for obtaining new information on the complex dynamics of neutral gas in the Galactic center.