Thomas Lizée – From molecular gas to stars: Constraining the properties of resolved gas and dust disks of local spiral galaxies

Speaker : Thomas Lizee (Obs de Strasbourg)

Title: From molecular gas to stars: Constraining the properties of resolved gas and dust disks of local spiral galaxies

Milky Way observations have provided insight into the scaling relations of molecular clouds and their ability to form stars. However, these relations cannot be established in nearby galaxies due to the limited spatial resolution of available observations. Starting from the multiphase, multiscale analytical model of Vollmer et al. 2017, whose goal is to describe galaxies as clumpy turbulent accretion disks, we improved the model and applied it to a sample of 17 local spiral galaxies. We generated radial profiles of large-scale quantities (SFR, stars, total gas) as well as molecular line emissions of different species (CO, HCN, HCO+) and compared them to multi-wavelength observations. The model is then able to predict key properties of the ISM such as the Toomre parameter Q, the gas velocity dispersion, the characteristic timescales of molecular clouds (free fall, molecular gas formation and turbulent times) as well as the CO-to-H2 and HCN-to-H2(dense) conversion factors. We conclude our study by reproducing the radial profiles of a Virgo cluster galaxy, NGC 4654, affected by both ram pressure stripping and gravitational interactions to better understand how the ISM properties reacts to such perturbations.