A targeted survey for H i clouds in galaxy groups |
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Authors: | Martin A. Zwaan &dagger |
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Affiliation: | Kapteyn Astronomical Institute, PO Box 800, 9700 AV Groningen, the Netherlands |
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Abstract: | Five galaxy groups with properties similar to those of the Local Group have been surveyed for H i clouds with the Arecibo Telescope. In total 300 pointings have been observed on grids of approximately 2.5×1.5 Mpc2 centred on the groups. The 4.5 σ detection limit on the minimal detectable H i masses is approximately 7×106 M⊙ ( H 0=65 km s−1 Mpc−1) . All detections could be attributed to optical galaxies; no significant detections of H i clouds have been made. This null result leads to the conclusion that the total H i mass of intragroup clouds must be less than 10 per cent of the total H i 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. |
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Keywords: | ISM: clouds intergalactic medium Local Group galaxies: luminosity function, mass function radio lines: ISM |
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