Project Details
Projekt
A comprehensive census of the multi-scale matter cycle within galaxies
Applicant
Dr. Mélanie Chevance
Subject Area
Astrophysics and Astronomy
Term
since 2021
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 465964231
Galaxies are in constant evolution, under the influence of the matter cycle within them: gas clouds assemble and collapse, stars form within them, and matter and energy are redistributed into the interstellar medium through the influence of stellar feedback and turbulence. The physical processes driving this cycle occur on the small scales of giant molecular clouds (GMCs, ∼100 pc), but govern the evolution of entire galaxies. In turn, the large-scale evolution of galaxies across space and time directly affects the cloud-scale environment from which stars form. It is one of the big unanswered questions in modern astrophysics which processes drive this multi-scale matter cycle, from the small-scale GMCs within which stars form, to large-scale, feedback-driven outflows, and what its quantitative characteristics are. In order to self-consistently model the processes driving the multi-scale matter cycle, numerical simulations of galaxy formation and evolution would require a comprehensive model spanning scales from tens of Mpc down to a few AU, over the complete history of the Universe. This is computationally much too demanding. This problem can be solved using sub-resolution prescriptions of the physics, but we urgently lack the required observational constraints to provide these as a function of the galactic environment. The key missing ingredient is a way of observationally quantifying the mass and energy flows within galaxies. This has been a major challenge, because observations of an individual region necessarily only capture a single snapshot of this matter cycle. With this Emmy Noether Programme, the PI will take the next major step in quantifying the matter cycle in galaxies. The physical processes driving this complex cycle are multi-scale and in order to fully constrain them, strong synergies are required between high-resolution, high-sensitivity observational surveys across the electromagnetic spectrum, and state-of-the-art simulations of galaxy formation and evolution. By combining an unprecedented variety of in-hand, multi-wavelength observations of a large range of galactic environments, the PI will characterise for the first time the successive steps of the matter cycle, from the assembly of dense gas clouds from the diffuse interstellar medium, to the successive collapse, star formation and dispersal by stellar feedback redistributing matter and energy back into the diffuse medium. The PI will determine the input and output energy, mass and momentum fluxes for each of these steps, thereby fully defining the cycle of matter within galaxies. By comparing these unique observational measurements with numerical simulations, the PI will identify the concrete elements of the sub-resolution models used in galaxy simulations that require improvement.
DFG Programme
Independent Junior Research Groups
International Connection
Australia, Canada, France, USA
