Shock-Induced Starburst and Star Cluster Formation in Colliding Galaxies

摘要

We performed high resolution simulations of galaxy-galaxy merg-ing in order to investigate the mechanism of a starburst. The multiphase nature of the interstellar medium is correctly taken into account in our model, which allows the use of a realistic star formation model. In these simulations, we for the first time found that the shock-induced starburst involving star cluster (SC) formation takes place during the first encounter. Detailed analyses show that the SC formation is mainly driven by hierarchical mergings of proto (smaller) SCs. Our result implies that SCs can become much more massive than the local Jeans mass of the SC forming region.