| Abstract | Extended H I envelopes around the Sa-galaxies NGC2655 and the Sc-galaxy NGC2715 are studied. Observations were done with the 100 m radiotelescope in Effelsberg. Global properties of the galaxies are given, including optical extent, inclination, H I radial velocity, integrated H I flux, line widths, total mass and luminosity. All galaxies known to have a ratio of H I diamater to optical diameter of 2.5 or larger, or more than two times the Holmberg diameter, are given along with their Hubble and luminosity type, H I diameter, coding for structure of H I extension and character of the galaxy, sensitivity limit of observations, and ratio of H I diameter to optical diameter. It is suggested that the circumgalactic gas is the leftover gas from merging galaxies already enriched with heavy elements, and that the extended H I in late-type and extended interacting galaxies should be identified with the gas producing low excitation absorption lines in quasars. |
