Implications for the formation of star clusters from extragalactic star formation rates

摘要: Observations indicate that young massive star clusters in spiral and dwarf galaxies follow a relation between luminosity of the brightest cluster formation rate (SFR) host galaxy, sense higher SFRs lead to brighter clusters. Assuming empirical maximum SFR reflects an underlying similar mass (M ecl,max ) SFR, we compare resulting SFR(M with different theoretical models. The correlation is found suggest individual form on free-fall time-scale their pre-cluster molecular-cloud-core radii typically being few parsecs independent mass. cloud cores contract by factors 5-10 while building up embedded cluster. A very good agreement obtained if CMF population has Salpeter exponent β 2.35 this forms within characteristic 1-10 Myr. This short can be understood interstellar medium pressurized, thus precipitating rapid local fragmentation collapse galactic scale. Such triggered scale observed occur interacting galaxies. With global 3-5 M ○. yr -1 , Milky Way appears lie relation, given recent detections masses near 10 5 Galactic disc. properties stellar suggests there may exist fundamental mass, 6 < */M 7 .