NGC-1569 - THE MOLECULAR AND IONIZED-GAS NEAR THE SUPERLUMINOUS STAR-CLUSTER-A AND STAR-CLUSTER-B

The starburst in the irregular galaxy NGC 1569 has produced two superl uminous star clusters A and B which strongly influence their surroundi ngs through UV radiation, stellar winds, supernova explosions, and an outflow of very hot gas. Close to A and B is located the most prominen t H II region of NGC 1569; our CO observations indicate that it contai ns similar to 2 10(6) M(.) molecular gas which probably still feeds st ar formation of its internal stellar cluster. When comparing the molec ular gas mass, calculated for Galactic conditions, and the virial mass we obtain a conversion factor similar to 20 times higher than the Gal actic value. However, we believe that the molecular clouds near the st ellar clusters are not in kinematic equilibrium so that the virial the orem does not apply; we therefore reject this conversion factor as unr ealistic. Our spectroscopic observations seem to indicate an optical c ounterpart of the Hr cavity around A, though being smaller in extent, and a surrounding shell of ionized gas of similar to 50 pc diameter. T he compact galaxy NGC 1705 contains a stellar cluster even brighter th an A and B. We did not detect CO in this galaxy.