The Frequency of Warped HI Discs
We have recently made a small survey of ten edge-on galaxies, using the VLA in D-configuration (resolution 40″) in the 21-cm line. The purpose was to find non-warped galaxies extended in HI, suitable for a detailed study of the vertical equilibrium of their stellar and gas disks. Such a study might help to determine the shape of the dark halo component. As a byproduct, we have found several more examples of warped HI-discs. In Table 1 we collect the data on edge-on galaxies either observed by us, or already published elsewhere. For small warp amplitudes resolution effects become important: e.g. for NGC 100 our 40″ data does not indicate a warp, but recent mapping at 4″ resolution show a warp of small amplitude, as well as the expected flaring of the HI disc.
- Rupen, M.: 1989, Ph. D. thesis, Princeton UniversityGoogle Scholar