THE UNUSUAL TAIL OF THE TORNADO NEBULA

We present high-resolution studies at 4.79 and 5.84 GHz, made with the Australia Telescope. These, complemented by 10.55 GHz observations ma de with the Effelsberg 100 m telescope, show clear evidence for polari zed looplike structure within the Tornado nebula G357.7-0.1. The trans verse magnetic field appears to be tangential to the loops, suggesting that a spiral magnetic structure extends from the head to the tail of the nebula. Our observations confirm that the compact source near the head of the Tornado is extended, has a flat spectrum, is probably the rmal, and unlikely to be related to the nebula. The symmetry and polar ized structure are difficult to explain, but the following are worth i nvestigating: interacting galaxies, slowly precessing Galactic or extr agalactic jets, or a supernova blast wave intersecting a preexisting s piral magnetic structure.