Bi-Qing For, Lister Staveley-Smith, Naomi M. McClure-Griffiths
We present a new catalog of high-velocity clouds in the region of the Magellanic Leading Arm. The catalog is based on neutral hydrogen (HI) from the Parkes Galactic All-Sky Survey (GASS). Excellent spectral resolution allows clouds with narrow-line components to be resolved. The total number of detected clouds is 407. We describe the method of cataloging and present the basic parameters of the clouds. We discuss the general distribution of the high-velocity clouds and classify the clouds based on their morphological type. The presence of a significant number of head-tail clouds and their distribution in the region is compared with simulations. We suggest that ram-pressure stripping is a more important factor than tidal forces for the morphology and formation of the Magellanic Leading Arm and that different environmental conditions might explain the morphological difference between the Magellanic Leading Arm and Magellanic Stream. Using the velocity structure of the Leading Arm we derive the distance for the clouds to be ~30 kpc. We also report a new population of clouds that forms the LA IV and a new diffuse bridge-like feature connecting the Leading Arm II and III complexes.
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http://arxiv.org/abs/1208.5583
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