Self-propagating star formation in the supergiant shell LMC 2

Supergiant shells are the largest interstellar structures in galaxies and play an important role in the global structure and evolution of the interstellar medium. Most supergiant shells seem to be formed by the collective action of fast stellar winds and clustered supernova explosions of massive stars. The dynamic age of a supergiant shell (several times 10⁷ yr) is much larger than the evolution timescale of massive stars (a few times 10⁶ yr). If supergiant shells are created by stellar winds and supernovae, massive stars must be formed continuously to supply the necessary energy, which implies that the shell triggers secondary star formation. We searched for the resulting stellar age gradient inside supergiant shell LMC 2. Preliminary analysis indicates a radial change of the stellar population, which may indicate triggered star formation from LMC 2.