The goal of the project is to study the global processes related to star formation on all spatial scales. This starts on large scales where the diffuse atomic gas forms molecular clouds which then collapse and form stars on small scales. During these processes, atomic gas converts to the molecular phase, clouds become dense and fragment and accretion disks and their associated outflows form. The physical scales covered range from several 10ths of parsec clouds to accretion disks sizes on the order of 100AU.
The project is observationally driven and based on two PI-led large observing programs at two of the most advanced radio and mm interferometers, the Very Large Array (VLA), and the Northern Extended Millimeter Array (NOEMA, formerly known as Plateau der Bute Interferometer, PdBI). The THOR program at the VLA investigates the cloud formation and conversion of atomic to molecular gas, as well as feedback processes back to the interstellar medium (ISM). To reach these goals, THOR observes the Milky Way in atomic HI, molecular OH, and cm continuum and radio recombination lines tracing the ionized components of the ISM. At smaller spatial scales, the CORE conduceted with NOEMA studies the fragmentation of the gas clumps to form clusters, the formation of accretion disks and outflows, and the gas infall rates as proxy for the accretion rates. Assisted by Atacama Large Millimeter Array (ALMA) observations, we are investigating a sample of high-mass star-forming regions at the highest spatial resolution of (<=0.2’’) to dissect the physical processes during the assembly of the highest mass stars.
Over the entire ERC project time, we managed to analyse and set into context the cloud and star formation processes from scales of several 10 parsecs down to several 1000 astronomical units. We characterised a dynamic picture where the gas flows from the cloud to protostellar scales, and then at later evolutionary stages the feedback processes give back energy and material to the interstellar medium, recycling in the whole cycle. These scientific results are documented by more than 90 refereed journal articles.
