MULTIFREQUENCY RADIO STUDIES OF G359.1-00.2

The Molonglo Observatory Synthesis Telescope, the Australia Telescope Compact Array, and the Very Large Array have been used to carry out im aging and polarimetry experiments on the unusual Galactic center filam entary object G359.1-00.2 also known as ''the Snake.'' The observation s were carried out at 843, 1446, 4790, 5840, and 8640 MHz, with resolu tions as fine as 2''. The images reveal intricate internal structure i n the object and physical properties similar to previously recognized filamentary features in the region. Several models of the source are d iscussed, with some form of electrodynamic activity being favored at p resent. It is not possible, however, to rule out all other models disc ussed-a jet or ejectum from a supernova event, a star wake or trail, a shock front, a phenomenon related to a cosmic string or the nearby '' Great Annihilator,'' 1E1740.7-2942, a morphologically unusual supernov a remnant-conclusively. Several models do predict observable changes i n the source on timescales of years, so further observations will help clarify this issue. A fractional linear polarization as high as simil ar to 50% was found for part of the Snake, although some regions of th e source are completely depolarized. The frequency dependence of the o bserved polarization properties suggests a model of the source as a tw isted ribbon embedded in a thermal medium giving rise to an external r otation measure of at least 5500 rad m(-2), with strong depolarization due to an internal Faraday depth of up to 1400 rad m(-2). The derived properties of the thermal medium in this model require a thermal elec tron density of 10 cm(-3) with a line-of-sight magnetic held strength of 7 mu G along a path of length similar to 100 pc, These parameters a re consistent with material in a nuclear disk in the Galactic center.