4.4 NGC 1216
This galaxy belongs to the Hickson compact group H 23. It is an almost
edge-on disk galaxy classified as S0-a in the LEDA database.
Counterrotation in the ionized gas is detected from optical emission lines
(Rubin et al. 1991). The gaseous disk extends up to a radius of 2 kpc,
with an observed maximum rotational speed of 75 km s^-1^; this velocity
is significantly lower than that of the stars at the same radius
(~175 km s^-1^). The latter may be an indication that the gaseous disk is
either warped or tilted with respect to the galaxy plane. The optical
images of this galaxy show no signature of dust absorption.
Williams & van Gorkom (1995) report a negative detection for this galaxy
in the 21 cm line, which gives an upper limit of M_HI_ < 5 x 10^7^ M_sun_.
IRAS, ROSAT and, finally, our CO observations report negative detections
for NGC 1216. The latter give an upper limit of M_mol_ < 3 x 10^8^ M_sun_
for the molecular gas content, within a region of radius r = 7 kpc.