A MOLECULAR GAS BAR FUELING STARBURST ACTIVITY IN GALAXY IC342

Starburst galaxies are those that are presently forming stars at a higher rate than that averaged over the galactic lifetime. Starburst galaxies usually exhibit strong CO line emission, indicating that they contain large amounts of molecular gas which fuels star formation. We have mapped CO(J Combining double low line 1 → 0) line emission from the central region of a late-type spiral galaxy IC342 using the Nobeyama Millimetre Array at a resolution of 2.4". We find a pair of narrow ridges of molecular gas, offset and forming a ring-like structure in the galactic nucleus; the motion of the gas in these bars is highly non-circular. This structure is very similar to that of the gas in the elliptical gravitational field of barred spiral galaxies. Strong radio continuum emission in the nuclear region suggests that it may be a site of starburst activity; if so, it is possible that the activity is being fuelled by the molecular gas bars. © 1990 Nature Publishing Group.