par Lise Ramambason (University of Heidelberg)
Abstract :
Nearby galaxies observed at high spatial resolution with JWST, ALMA, and MUSE allow us to probe the multiscale feedback processes, from giant molecular clouds to galactic scales. A key question is how ionizing photons propagate through the complex, multiphase interstellar medium (ISM): what allows them to escape from H II regions, and how do they reshape the surrounding gas?
I will present results from the PHANGS-JWST survey on the earliest dust-embedded phase of star formation within molecular clouds. These observations show that the local structure, chemistry, and porosity of the ISM regulate the early stellar feedback and potential escape of ionizing radiation.
Even when this small-scale structure is unresolved, its imprint remains in galaxy spectra. I will introduce a novel statistical framework that uses integrated emission lines to recover key aspects of the ISM geometry and constrain the underlying distributions of parameters such as the density, ionization parameter, or escape
fraction. Together, these approaches link resolved studies of nearby galaxies to unresolved observations of local and high redshift galaxies, providing a consistent way to interpret how stellar feedback shapes galaxies across cosmic time.
Lieu : IAS, bât. 209D, salle de cours au RDC, à 11h