Resolving the extragalactic ISM with HST extinction: impact of environment

by Dr Helena Faustino Vieira

Friday 24 Jan 2025, 10:30 → 11:30 Europe/Stockholm

FC61 (AlbaNova Main Building)

The question of whether star formation is directly affected by the large-scale dynamics within a galaxy, or merely dependent on the local conditions of the interstellar medium (ISM), is a matter of long-standing debate. This is hindered by the difficulty in simultaneously probing the small-scales associated with the star formation process, and the large-scales which might regulate the formation and evolution of molecular clouds, where stars form. Therefore, significant advancement can only be achieved with high-resolution imaging of entire galaxies, such that the properties of molecular clouds are resolved whilst maintaining the galactic context.

I present my work on studying the resolved properties of the ISM by exploiting the high-resolution data from HST in nearby spiral galaxies to its full potential (in combination with JWST data). I will showcase how, with a novel technique to derive dust extinction using optical HST data, we can retrieve maps of the dust (and gas) content across entire galaxies at unprecedented resolution. For our sample of nearby galaxies, our maps have resolution corresponding to a few parsecs, allowing us to study the extragalactic ISM with a level of detail typically only achieved with Galactic studies. Our study of M51 using this technique has shown that there are clear changes in the properties of the ISM depending on the galactic environment as well as on the type of spiral potential felt by the gas. I will also present preliminary results of the application of this technique to a larger sample of nearby spirals.