The First Complete and Fully Sampled HI Survey of the Tidal Arms of the Magellanic System

Abstract

The LMC, SMC, and the Milky Way are a spectacular set of interacting galaxies. The prominent tidal arms which protrude from the Magellanic Clouds extend for tens of kiloparsecs and cover a large part of the southern sky. These arms, and the Magellanic Clouds themselves, are therefore a highly suitable subject for the detailed investigation of an interacting galaxy system. We present the first results of the Parkes narrow-band HI survey of the tidal arms of the Magellanic System. It is the first fully sampled, spatially complete survey of this system. The data provide information on the column density distribution and the variation of the shape of the line profiles over the extent of the tidal features. We present a cloud catalogue of the tidal features of the Magellanic System and discuss the distribution relative to the observational parameters longitude, latitude and radial velocity (v_LSR and v_GSR). We find a new stream-like feature that is most likely related to the Leading Arm. Detailed investigation reveals a number of clouds showing a cometary appearance in the position-velocity representation (so-called head-tail structures). These head-tail structures are interpreted as clouds that are currently interacting with an ambient medium.