NGC 1365 is a southern, strongly barred spiral galaxy
with no apparent companions. VLA HI observations by Ondrechen
& van der
Hulst (1989) show the overall gas extent of the galaxy. The central region
contains a Seyfert nucleus as well as circum-nuclear radio continuum and
H
emission, indicating star formation (Saikia et al. 1994; Sandqvist,
Jörsäter & Lindblad 1995). Ondrechen & van der Hulst find a strong
absorption feature centred at 1570 kms-1 with a width of only
33 kms-1. But their position-velocity diagrams indicate a much
broader (
kms-1) feature which is confirmed by
Jörsäter & van Moorsel (1995) who find a total velocity width of
313 kms-1 for the HI absorption. Our own ATCA snap-shot
observations of NGC 1365 and also NGC 1097, another strongly barred galaxy,
clearly reveal HI absorption over a broad velocity range. The broad
absorption features are most likely caused by a rapidly rotating ring/disk
of neutral gas. For NGC 1365 a similar disk of ionized matter with a radius
of 7 has already been inferred by Lindblad (1978). NGC 1097 is in
many respects very similar to NGC 1365 (see Ondrechen, van der Hulst &
Hummel 1989).
The continuum sources of both galaxies are displayed in Fig. 4.
Figure 4:
20-cm radio continuum emission of the starburst galaxies NGC 1365
and NGC 1097. These data were taken with the largest array of the
ATCA (snap-shot). The beam has been convolved to 8.