The small-scale structure of the Magellanic Stream

Five regions in the northern part of the Magellanic Stream have been surveyed at high sensitivity with an angular resolution of 00.20 and a velocity resolution of 1.8 km s-1, in order to study their small-scale structure. The regions show narrow filamentary structure running parallel to the main direction of the Stream, and containing small cloud-like concentrations. Results are presented for the typical angular half-power widths and velocity half-power widths, typical masses, and preferential orientation of the clouds. The mean velocity differences between adjacent clouds appear to increase systematically towards the tip of the Stream, but there is no evidence for any variation in cloud parameters along the Stream, or for systematic motions within the individual clouds. The clouds appear to be unstable over the lifetime of the Stream as a whole, and some external containment mechanism seems to be necessary to preserve the small-scale structure. A number of possible mechanisms are discussed. (author)