High-Velocity Clouds Related to the Magellanic System

Abstract

The results of the interaction between the Milky Way and the Magellanic Clouds are revealed through several high velocity complexes which are connected to the Clouds. The exact mechanism of their formation is under some debate, but they remain the only group of high-velocity clouds (HVCs) for which we have an origin and roughly a distance. Given that, the Magellanic HVCs can be used as a calibrator for other HVCs, while also providing an opportunity to closely investigate the remnants of an interacting system. These HVCs may hold the key to the star formation history, kinematic structure, and present Hubble type of the Magellanic Clouds, and their proximity to the Milky Way allows us to estimate key Galactic parameters. The HVCs related to the Magellanic System can be classified into three major complexes: the Magellanic Bridge, an HI connection between the Clouds; the Magellanic Stream, which trails the clouds and is one of the largest HI features in the sky outside of our Galaxy; and the Leading Arm, a more diffuse HI filament which leads the Clouds. In terms of HVCs, these features have been studied rather extensively. In this review, I will first describe the observational results for each complex and subsequently discuss their origin and relationship to the overall HVC population. All of the HI data presented are from the HI Parkes All-Sky Survey (HIPASS) (Barnes et al. 2001; Putman et al. 2001).