Fakultät für Physik und Astronomie
STEPHEN PHILLIPS hostreviews.co.uk / UNSPLASH

Environmental dependence of the matter cycle from cloud evolution to star formation and feedback in 54 main sequence galaxies

Jaeyeon Kim , ARI

The processes of star formation and feedback take place on the cloud scale (~100pc) within galaxies and play a major role in governing galaxy evolution. The properties of the clouds in which stars form are set by the large scale environment of their host galaxies, directly linking the initial conditions of star formation to galactic-scale properties. In turn, the energy, momentum,and mass deposited by stellar feedback drive the continuous evolution of the interstellar medium at large. Characterising the physical mechanisms regulating this multi-scale cycle is therefore crucial to understand the evolution of galaxies. By applying a new statistical method to the high-resolution CO and narrowband-Halpha imaging from the PHANGS survey, we systematically measure the evolutionary timeline from molecular clouds to exposed young stellar regions on the scales of giant molecular clouds across an unprecedented sample of 54 main sequence galaxies. We find that clouds live for about one dynamical time (8-30 Myr) and are efficiently dispersed by stellar feedback within 1.2-5.1 Myr after the star-forming region has become partially exposed. These ranges do not indicate uncertainties, but reflect physical galaxy-to-galaxy variation, implying an important dependence of these timescales on the local conditions, shaped by the galactic environment. The statistically representative PHANGS sample covers a large range of galaxy properties and morphologies, which allows us, for the first time, to quantitatively link galactic-scale environmental properties to the small-scale evolutionary cycle of molecular clouds, star-formation, and feedback. I will present the first census of these multi-scale trends. These results enable the characterisation of the physical mechanisms regulating cloud assembly, star formation, and cloud disruption, which eventually participate in driving galaxy evolution, as a function of the galactic environment.

ARI Institute Colloquium
10 Feb 2022, 11:15
ARI, Moenchhofstrasse 12-14, Seminarraum 1, 1.OG

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