HI in the shell elliptical galaxy NGC 3656

Very Large Array(7) neutral hydrogen observations of the shell elliptical g alaxy NGC 3656 reveal an edge-on, warped minor-axis gaseous disk (M (H I) s imilar to 2 x 10(9) M-circle dot) extending 7 kpc. H I is also found outsid e the optical image, on two complexes to the northeast and northwest that s eem to trace one or two tidal tails, or possibly an outer broken H I disk o r ring. These complexes link with the outer edges of the inner disk and app ear displaced with respect to the two optical tails in the galaxy. The disk kinematics is strongly lopsided, suggesting recent or ongoing accretion. I ntegral-field optical fiber spectroscopy at the region of the bright southe rn shell of NGC 3656 has provided a determination of the stellar velocities of the shell. The shell, at 9 kpc from the center, has traces of H I with velocities bracketing the stellar velocities, providing evidence for a dyna mical association of H I and stars at the shell. Within the errors the star s have systemic velocity, suggesting a possible phase-wrapping origin for t he shell. We probed a region of 40' x 40' (480 kpc x 480 kpc) x 1160 km s(- 1) down to an H I mass sensitivity (6 sigma) of 3 x 10(7) M-circle dot and detect five dwarf galaxies with H I masses ranging from 2 x 10(8) to 2 x 10 (9) M-circle dot, all within 180 kpc of NGC 3656 and all within the velocit y range (450 km s(-1)) of the H I of NGC 3656. The dwarfs had been previous ly cataloged, but none had a known redshift. For the NGC 3656 group to be b ound requires a total mass of (3-7.4) x 10(12) M-circle dot, yielding a mas s-to-light ratio from 125 to 300. The overall H I picture presented by NGC 3656 supports the hypothesis of a disk-disk merger origin or possibly an on going process of multiple mergers with nearby dwarfs.