High velocity clouds from local group dwarf galaxies and Lyman-α clouds

The possible connection between High Velocity Clouds (HVCs) and Lyman-cr absorbers seen in QSO spectra at low redshift is investigated. 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. As clusters of dwarf galaxies at high redshifts merged to form L-* galaxies and the gravitational potential of the merging galaxy increases, tidal stripping might occur. The gas then infalls onto the L-* galaxy. The tidally stripped gas would then give rise to a fraction of the Ly alpha systems seen in QSO spectra.