The interstellar medium and star formation in nearby galaxies

Abstract

AbstractIn this overview article we present some of the key projects we pursue in our Emmy Noether group. Our work is focused on nearby galaxies, where we use multi‐wavelength, state‐of‐the‐art survey data to probe distribution, abundance and properties of gas and dust in the interstellar medium (ISM) on ∼ kpc scales. We study the average, radial distributions of atomic (H I) and molecular hydrogen (H2) across the disks of spiral galaxies and assess local (on 1 kpc scales) correlations between H I, H2 and star formation rate (SFR) surface densities across the inner, optical disks of our sample of ∼ 30 spiral galaxies. The short H2 depletion times (∼ 2 Gyr) we find raises the question of if and how star formation is refueled in galactic disks. We look for such signatures of radial gas flows in our H I data and find compelling evidence at least in one case. We extend and compare our gas‐SFR studies to the outer disks of galaxies, where conditions change significantly in the ISM, e.g., low metallicity and dust abundance. We focus on star formation at low‐metallicity further with detailed ISM studies in dwarf galaxies, where we combine spectroscopic observations in the infrared with detailed modelling to learn about composition and detailed physical properties of the ISM. Of particular interest is the question of what drives large scale star formation in galaxies at low metallicity. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)