Neutral hydrogen gas in 7 high-inclination spiral galaxies I. The data

Abstract

High-sensitivity interferometric H I line observations of a small sample of seven galaxies with limiting column densities of a few times 1019 cm-2 are presented. A tilted ring model fitting routine was used to determine some global characteristics of the H I distribution and kinematics in the galaxy disks. 4 of the 7 galaxies have low maximum rotation velocities of ≲125 km s-1, indicating that they are low-mass systems. Visual inspection shows that at least one galaxy, NGC 4700, exhibits signs of extraplanar Hi emission. An in-depth search for Hi gas in the galaxy halos and the determination of halo gas properties, based on three-dimensional modeling, will follow in a separate publication. Companion galaxies were detected in Hi line emission near 3 of the 7 sample galaxies: NGC 1511, NGC 4565 and NGC 4700. One of these, NGC 1511, is found to be strongly interacting and is therefore not suitable for a study of the dependence of its halo properties on the level of star formation activity in the underlying disk. In the case of NGC 4700 the companion galaxy has no visible influence on its gas kinematics, while NGC 4565 might be affected by its interaction with two small companions. © ESO 2005.