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Paper: Tidal Streams and Low Mass Companions of M31
Volume: 327, Satellites and Tidal Streams
Page: 139
Authors: Braun, R.; Thilker, D.
Abstract: We have imaged the extended H I environment of M31 with an unprecedented combination of high resolution and sensitivity. We detect a number of distinct high velocity cloud components associated with M31. A subset of the features within 30 kpc appear to be tidal in origin. A filamentary “halo” component is concentrated at the M31 systemic velocity and appears to extend into a “bridge” connecting M31 and M33. This may represent condensation in coronal gas. A population of discrete clouds is detected out to radii of about 150 kpc. Discrete cloud line widths are correlated with H I mass and are consistent with a 100:1 ratio of dark to H I mass. These may be the gaseous counterparts of low-mass dark-matter satellites. The combined distribution of M31's HVC components can be characterized by a spatial Gaussian of 55 kpc dispersion and yields an NH I distribution function which agrees well with that of low red-shift QSOs.
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