M51
Galaxy (Whirlpool, NGC5195)
Located at a distance of 37 million light-years from us, the famous
M51 Galaxy (Sc type) was discovered in 1773 by Charles Messier.
Due to its orientation in space, it is seen "face-on".
Optical image of M51.
Left
: Continuum emission at 1.3 mm from the cold dust (<20K) contained
in the spiral arms of M51 as observed with the 30m telescope.
in the spiral arms of M51 as observed with the 30m telescope.
Right:
Map of the CO(2-1) emission from M51.
The
pixel size in both images is 12 arc seconds. The continuum emission of
cold dust closely follows the spiral pattern traced by the CO emission
and correlates poorly with the emission from neutral hydrogen HI clouds.
Similar results have been obtained by mapping the "edge-on" galaxy NGC
891, where the dust correlates well with the CO emission up to a radius
of 25 thousand light-years from the center of the galaxy.