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| EPoS Contribution |
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Characterising the Cloud-Scale Physics of Star Formation and Feedback Beyond the Milky Way - Results from a Comprehensive Survey of Local-Universe Galaxies
Alexander Hygate MPIA/U Heidelberg, Heidelberg, DE | |
| The relation between gas mass density and star formation density is well-established for galaxies as a whole. However, it has become clear in recent years that this relation breaks down when considering smaller scales, such as those of individual molecular clouds. I will present a statistical method, validated with high-resolution disc galaxy simulations, that harnesses this breakdown of the star formation law at small scales to measure a great variety of key quantities characterising the cloud-scale physics of star formation and feedback. This method allows us to directly measure the molecular cloud lifetime, the feedback timescale, feedback outflow velocity, star formation efficiency, ISM instability length scale, and feedback-to-ISM coupling efficiency. Previous constraints on these quantities have been restricted to the Milky Way and a few very nearby galaxies. I will present systematic measurements of these quantities across more than a dozen galaxies in the Local Universe, including the LMC, M33, NGC300, and the wide range of systems covered by the PHANGS survey of nearby galaxies. In concert with modern high-resolution instruments such as ALMA and MUSE, we can now do "Milky Way science" in a large number of galaxies in differing environments from the local Universe out to tens of Mpc. I will show how these measurements probe the underlying physical processes driving SF, such as by using measured values of the feedback timescale to discriminate between different feedback mechanisms. These results reveal universally fast and inefficient star formation due to short molecular cloud lifetimes (6-30 Myr) and rapid stellar feedback (1-5 Myr), but also show that the details of the star formation and feedback process vary considerably with the galactic environment. By comparing these results to studies of the Milky Way, I will demonstrate that our (or any other single) galaxy provides only a limited (and possibly biased) view of the underlying physical complexity. Finally, I will highlight the challenges faced when applying this approach to such a wide variety of extragalactic environments and discuss some of the solutions that we have developed. | |
| Collaborators: D. Kruijssen, U Heidelberg, DE F. Walter, MPIA, DE A. Schruba, MPE, DE D. Haydon, U Heidelberg, DE S. Longmore, LJMU, UK M. Chevance, U Heidelberg, DE |
Suggested Session:
Star formation "laws" and IMF |