HI observations of loose galaxy groups - I. Data and global properties

At Nancay, 21-cm H I line observations were made of 15 spiral-dominated loose groups of galaxies, divided into two samples: an interacting sample containing at least one pair of interacting galaxies, and a control sample having no optical evidence of interactions or morphological disturbances among the group members. The interacting sample consists of 62 galaxies representing 9 different groups, and the control sample contains 40 galaxies representing 6 groups. Of the 91 galaxy and galaxy pairs observed, 74 were detected, while upper limits were placed on the remaining 17 objects. These homogeneous Hi data, which will be used in future analyses, provide comparative information on the Hi content of groups and serve as a probe of the vicinity of the target spirals for Hi clouds or very low surface brightness gas-rich galaxies.