MATs (Monday Afternoon Talks)

3:00pm – 3:30pm, Xinfeng Xu

What are the radial distributions of density, outflow rates, and cloud structures in the M82 wind?
Galactic winds play essential roles in the evolution of galaxies by providing various feedback effects. Despite intensive studies of winds, their radial distributions and feedback are rarely observable. I will present a new such measurement for the prototypical starburst galaxy, M 82, based on observations by the Subaru telescope. I determine the radial distribution of outflow densities and outflow rates based on the observed optical emission lines, and find that galactic wind in M 82 can carry mass, momentum, and energy from the central regions to a few kpc with minimal losses. I further derive novel outflow cloud properties, including size, mass, and column densities. The outflow clouds have pressures and densities that are too high and sizes that are too small to match those from recent theoretical models and numerical simulations of winds. By comparing with a sample of outflows in local star-forming galaxies in the COS Legacy Spectroscopic Survey (CLASSY), the above-derived properties for M 82 match well with the published scaling relationships and the cloud properties. These matches suggest that the ionized gas traced in emission and absorption are strongly related. These measurements motivate future spatially resolved studies of more galactic winds, which is the only way to map the structure of their feedback effects.