Tracking Down the Processes that Shape the ISM: The Case of the Supergiant Shell in IC 2574

We present new X-ray data (obtained with the Chandra telescope) as well as FUV data of the supergiant shell (SGS) in IC 2574, a dwarf galaxy in the M 81 group. This region has proven to be a unique target for studying the interplay of massive star formation with the surrounding interstellar medium. The Chandra data confirm the presence of soft X-ray emission, indicative of the presence of hot gas. Using optical and FUV data, we estimate the age and the energy input of the stellar cluster inside the SGS. The age estimate agrees well with the age estimated based on the HI data alone – providing further supportfor the view that the stellar cluster interior the SGS is powering its expansion. We conclude that indeed massive stellar clusters can create supergiant shells in galaxies (even at large galactocentric distance) as predicted by the 'standard' picture (creation by SN explosions and strong stellar winds), a scenario which has recently been questioned by some authors.