1996A&A...312..391G

The starburst in the irregular galaxy NGC 1569 has produced two superluminous star clusters A and B which strongly influence their surroundings through UV radiation, stellar winds, supernova explosions, and an outflow of very hot gas. Close to A and B is located the most prominent HII region of NGC 1569; our CO observations indicate that it contains ∼ 2x10⁶M_☉ molecular gas which probably still feeds star formation of its internal stellar cluster. When comparing the molecular gas mass, calculated for Galactic conditions, and the virial mass we obtain a conversion factor ∼ 20 times higher than the Galactic value. However, we believe that the molecular clouds near the stellar clusters are not in kinematic equilibrium so that the virial theorem does not apply; we therefore reject this conversion factor as unrealistic. Our spectroscopic observations seem to indicate an optical counterpart of the HI cavity around A, though being smaller in extent, and a surrounding shell of ionized gas of ∼50pc diameter. The compact galaxy NGC 1705 contains a stellar cluster even brighter than A and B. We did not detect CO in this galaxy.