We present neutral hydrogen (H{ \sc i}) observations with the Giant Metrewave Radio Telescope ({ \it GMRT}) of the interacting galaxies NGC5996 and NGC5994, which make up the Arp72 system. Arp72 is an M51-type system and shows a complex distribution of H{ \sc i} tails and a bridge due to tidal interactions. H{ \sc i} column densities ranging from 0.8$-1.8\times10^{ 20}$ atoms cm$^{ -2}$ in the eastern tidal tail to 1.7$-2\times10^{ 21}$ atoms cm$^{ -2}$ in the bridge connecting the two galaxies, are seen to be associated with star-forming regions. We discuss the morphological and kinematic similarities of Arp72 with M51, the archetypal example of the M51-type systems, and Arp86, another M51-type system studied with the { \it GMRT}, and suggest that a multiple passage model of Salo & Laurikainen may be preferred over the classical single passage model of Toomre & Toomre, to reproduce the H{ \sc i} features in Arp72 as well as in other M-51 systems depicting similar optical and H{ \sc i} features.
Categories: astro-ph.CO
