| Abstract | The five central galaxies of the NGC 697 group have been observed in the 21-cm line of neutral hydrogen using the VLA in the D configuration. The observations show basically unperturbed H I in NGC 691, NGC 694, and IC 167, and an extended H I region enveloping NGC 678 and NGC 680. On the basis of the observed velocities, this H I is shown to be related to NGC 678 and not to NGC 680, the only elliptical in the group. For the other four galaxies total masses were determined on the basis of the internal kinematics. An extended H I region, which is not connected to any of the visible galaxies, was detected close to the centre of the group. Several determinations, based on various mass estimators, gave similar values for the total mass in the NGC 697 group. Assuming dynamical equilibrium in the group, the ratio total mass/luminous mass is shown to be of the order of 10. |
