Self-regulated star formation in galaxy and the evolution of the molecular web
LMU, University Observatory, Munich, Germany
|Despite the fact that a large fraction of the interstellar gas in galaxies is confined to cold and dense molecular clouds, their star formation rates are moderate, indicating that clouds are either long-lived or star formation is very inefficient. Interstellar turbulence, driven by gravitational disk instabilities, stellar feedback, gas accretion from the cosmic web and the viscous evolution of galactic disks is believed to provide the required support against global collapse of molecular clouds. The situation is however more complex. I will discuss numerical simulations of the self-regulated evolution of galaxies, fed by gas infall, that show that the molecular gas is distributed in a complex, highly dynamical molecular web. The fractal structure of the web is in good agreement with observations. Molecular clouds are not isolated but represent high-density nodes that are continuously fed by accreting new gas, while at the same time loosing mass through star formation and stellar feedback. Galaxies are not isolated. The mass loading of the molecular web is determined by their global gas accretion rate from the cosmic web which also determines the galactic star formation rate and which links the evolution of galaxies to cosmic structure formation.
Clare Dobbs, Exeter, UK
James Pringle, Cambridge, UK
Eva Ntormousi, USM, Munich, DE
Lee Hartmann, Michigan, US