Interstellar medium and star formation in extremely metal-poor galaxies, Vianney Lebouteiller (CEA)

The interstellar medium (ISM) is a fundamental component of galaxies, participating in the complex network responsible for star formation and galaxy evolution. Star formation, which occurs in cold dense clouds subject to gravitational instabilities, is affected by dynamical feedback but thermal processes also play an essential role, especially in a primitive (metal-poor) ISM. The abundance of heavy elements in the ISM is therefore a crucial parameter, through the formation of dust particles, of molecular hydrogen, and of important gas-cooling species. These processes participate in the shielding from photodissociating UV photons and/or in controlling the thermal balance of the gas. The Nearby Universe includes galaxies with metallicities down to 3% of that of the Milky Way. This provides us with the opportunity of examining and understanding the impact of metallicity on the ISM properties, the star-formation process, and in general galaxy evolution, in conditions approaching those potentially found in a primordial environment. In this seminar, I will present recent results concerning dust and gas properties in a sample of extremely metal-poor galaxies.