VLA observations of H I absorption in the nuclei of Seyfert and active galaxies

Spiral galaxies with strong nuclear radio-continuum emission have been surveyed for H I absorption at 21 cm wavelength. Eight galaxies show clear or tentative absorption lines. The absorption line centers are offset from the galaxy systemic velocities by up to 300 km s/sup -1/; for the entire sample, there is an overall preference for infall of gas toward the nulceus rather than outflow (+98 km s/sup -1/ median relative velocity). Cases with both positive and negative realtive velocities are apparent. The presence of absorption appears to be correlated with the inclination of the galaxies: edge-on systems are more likely to show absorption lines. For the detected lines, the total absorption (equivalent width) is much greater than would be expected from the disk of our Galaxy.