Abstract

Contributed Talk - Splinter MassiveStars

Monday, 09 September 2024, 17:15   (S23)

Molecular clouds roasted by starburst clusters

Thomas Stanke
Max-Planck-Institut für extraterrestrische Physik

According to the Jeans Criterion, the temperature of the dense gas, from which stars form, has a major impact on the masses of the cores (and stars) that result from the fragmentation of the gas. Feedback from the massive star population of freshly formed massive young clusters could be expected to have a significant impact on the dense gas physical properties surrounding these clusters and skew the stellar mass function resulting from star formation in such an environment. Star formation in the early Universe and around cosmic noon proceeded with a much more significant share of stars formed in starburst environments involving the formation of massive clusters, hence we could expect differences in the resulting stellar mass spectrum, if compared to, e.g., local Universe galaxies such as our Milky Way, which features hardly any objects that could be termed young massive clusters. We here explore to which extent thermal feedback from the massive star population in young massive clusters could potentially affect the outcome of further star formation in adjacent clouds due to heating the dense gas forming the next generation of stars. We use H2CO to measure the dense gas temperature distribution around a small sample of galactic young massive clusters. We find clear gradients - temperature falling with distance over scales of several parsecs - for NGC3603, RCW38, and DBS[2003]179, indicating that indeed feedback can have a profound impact on the dense gas temperature. To complicate the picture, however, we also find evidence for very cold (20K) gas even in the massive, 60K warm clumps directly exposed to the NGC3603 starburst cluster from N2H+ observations! This finding calls for a discussion on whether or not cold, dense gas or rather warm gas forms the next generation of stars in starburst environments, and whether this could have an effect on the resulting stellar initial mass function.