21-cm line studies of spiral galaxies. I - Observations of the galaxies NGC 5033, 3198, 5055, 2841, and 7331. II - The distribution and kinematics of neutral hydrogen in spiral galaxies of various morphological types

We have mapped the galaxies NGC 5033, 3198, 5055, 2841, and 7331 in the 21-cm line with angular resolutions such that the ratio radius/beam size is of order 5-10. For four of the five galaxies we find that both the H I distribution and the velocity field cannot be described by the simple picture of a spiral having an axisymmetric disk in differential rotation. For those four galaxies we show that the main deviations from circular motion can be described by a warping of the plane at large radii. The determination of the mass distributions for these galaxies is severely compromised by this. For all galaxies we find asymmetries in the H I distribution, and for most of them there are H I clouds in the outer parts which do not coincide with optical features. NGC 5055 and NGC 2841 have H I disks extending 2 and 2.5 times as far as the Holmberg radius. NGC 3198, NGC 2841, and NGC 7331 have a depression in the H I distribution in the central parts.