2001MNRAS.325.1142Z

Five galaxy groups with properties similar to those of the Local Group have been surveyed for Hi clouds with the Arecibo Telescope. In total 300 pointings have been observed on grids of approximately 2.5x1.5Mpc² centred on the groups. The 4.5σ detection limit on the minimal detectable Hi masses is approximately 7x10⁶M_☉ (H₀=65km.s^–1.Mpc^–1). All detections could be attributed to optical galaxies; no significant detections of Hi clouds have been made. This null result leads to the conclusion that the total Hi mass of intragroup clouds must be less than 10 per cent of the total Hi mass of galaxy groups and less than 0.05 per cent of the dynamical mass. The recent hypothesis that Galactic high-velocity clouds are Local Group satellite galaxies is highly inconsistent with these observations.