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Paper: High Velocity Clouds as Tidal Stripping from Local Group Dwarf Galaxies and their Connection to Lyman-alpha Clouds
Volume: 166, Stromlo Workshop on High-Velocity Clouds
Page: 138
Authors: Mallouris, Christoforos; Lanzetta, Kenneth M.; Burks, Geoffrey S.; York, Donald G.
Abstract: High velocity clouds (HVCs) are unlikely to be isolated phenomena to our Galaxy. If they are infalling matter on galaxies, or groups of galaxies, such systems of other galaxies should appear as QSO Ly alpha absorbers at the corresponding galaxy redshifts. The clouds in HVC systems should appear in absorption in the same way that Galactic HVCs appear as absorbers toward AGNs which happen to fall in the lines of sight to these clouds. We examine the possibility that the low z Ly alpha forest in QSO spectra is partly related to systems of HVCs in intervening groups of galaxies. The association is a result of hierarchical clustering, where clusters of dwarf galaxies at high redshifts merge to form Lstar galaxies. One can then imagine tidal stripping to occur as the gravitational potential of the merging galaxy increases. The gas then infalls onto the Lstar galaxy. This stripping might begin to occur at redshifts zapprox1. The tidally stripped gas would then give rise to a fraction of the Ly alpha systems seen in QSO spectra. The source function for the transient HVCs can be assumed to be the dwarf galaxies in the groups. The HVCs in the Local Group would have a similar origin.
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