| Abstract | An H I survey has been carried out on three fields covering most of the core of the Hercules cluster of galaxies (A2151) using the D-configuration of the VLA, and the results are reported. Thirty-one galaxies have been detected and the rotation signatures of 16 of these have been mapped. There is no preferred direction in the sky for the principal axis of this signature. The core of A2151, although elongated and clumpy, is probably a single dynamic unit, and the increase of systemic velocities decreases with increasing distance from the cluster core. There is a small increase of systematic velocities from south to north. |
