The physics of star cluster formation and evolution

arXiv:2005.00801v2Star clusters form in dense, hierarchically collapsing gas clouds. Bulk kinetic energy is transformed to turbulence with stars forming from cores fed by filaments. In the most compact regions, stellar feedback is least effective in removing the gas and stars may form very efficiently. These are also the regions where, in high-mass clusters, ejecta from some kind of high-mass stars are effectively captured during the formation phase of some of the low mass stars and channeled into the latter to form multiple populations. Star formation epochs in star clusters are generally set by gas flows that determine the abundance of gas in the cluster. We argue that there is likely only one star formation epoch after which clusters remain essentially clear of gas by cluster winds. Collisional dynamics is important in this phase leading to core collapse, expansion and eventual dispersion of every cluster. We review recent developments in the field with a focus on theoretical work.J.M.D.K. gratefully acknowledges funding from the German Research Foundation (DFG) in the form of an Emmy Noether Research Group (grant number KR4801/1-1) and a DFG Sachbeihilfe Grant (grant number KR4801/2-1), from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme via the ERC Starting Grant MUSTANG (grant agreement number 714907), and from Sonderforschungsbereich SFB 881 “The Milky Way System” (subproject B2) of the DFG. S.S.R.O. acknowledges funding from NSF Career grant AST-1650486. P.G. acknowledges funding from the European Research Council under ERC-CoG grant CRAGSMAN-646955. R.S.K. acknowledges support from the Deutsche Forschungsgemeinschaft via the SFB 881 “The Milky Way System” (subprojects B1, B2, and B8) as well as funding from the Heidelberg Cluster of Excellence STRUCTURES in the framework of Germany’s Excellence Strategy (grant EXC-2181/1-390900948). JBP acknowledges UNAM-DGAPA-PAPIIT support through grant number IN-111-219. MG acknowledges support from the ERC (CLUSTERS, StG-335936). E.V.-S. acknowledges financial support from CONACYT grant 255295.Peer reviewe