Astronomical Applications Department, U.S. Naval Observatory thesis Page 117
103
star formation triggering via HI supershells are found. This simple illustration
demonstrates that massive star formation can operate more easily as a feedback
mechanism in regions with uncomplicated global kinematical properties.
7.4.2 Random Motions
The rotation curve of IC2574 also demonstrates solid body rotation. However,
radii r
4
0
demonstrate noncircular motions due to the possible presence of
a bar potential. The isovelocity contours range from
,
10 to 110 km s
,
1
with
de nite noncircular motions between 20 and 80 km s
,
1
Martimbeau
et
al.
1994.
To mark the boundary between these characteristic di erences in the ISM of
IC2574, a 4
0
ellipse is reduced to the plane of the galaxy and plotted on the
FUV image in Fig. 7.13. The large northwestern complex, which demonstrates
large-scale triggering via HI shells, is located just outside the ellipse. Also found
on the exterior of the ellipse are the majority of the FUV-bright regions. Only
di use FUV patches are located inside the ellipse. As suggested previously, star
formation triggering via cloud collisions is a possible mechanism for star formation
r
4
0
since random motions contribute to cloud collisions.
