A wide-field H I study of the NGC 1566 group

We report on neutral hydrogen observations of a � 5.5 � × 5.5 � field around the NGC 1566 galaxy group with the multibeam narrow-band system on the 64-m Parkes telescope. We detected thirteen Hi sources in the field, including two galaxies not previously known to be members of the group, bringing the total number of confirmed galaxies in this group to 26. Each of the Hi galaxies can be associated with an optically catalogued galaxy. No ’intergalactic Hi clouds’ were found to an Hi mass limit of � 3.5×10 8 M�. We have estimated the expected Hi content of the late-type galaxies in this group and find the total detected Hi is consistent with our expectations. However, while no global Hi deficiency is inferred for this group, two galaxies exhibit individual Hi deficiencies. Further observations are needed to determine the gas removal mechanisms in these galaxies.