| Abstract | The authors have used the Westerbork Synthesis Telescope to map the high-velocity neutral hydrogen in the region of Stephan's Quintet with a resolution of ≡35arcsec. Three distinct velocity systems are seen, at 5700, 6000, and 6600 km s-1, and what is remarkable is that the bulk of the H I at all velocities lies outside the optical bounds of the Quintet galaxies. The authors interpret this result in terms of a collision among the high-velocity objects, including NGC 7320c, in which tidal and collisional stripping have succeeded in removing the majority of the disk gas from the interacting galaxies. Detection of H I in several galaxies near the Quintet provides evidence that the high-redshift objects are at distances commensurate with their redshifts. In this view, the apparent redshift discrepancy of Stephan's Quintet arises from the chance juxtaposition of two groupings of galaxies, at 800 and 6000 km s-1. |
