Reconstructing the full density structure of the star-forming interstellar medium

Research Project, 2026 – 2029

Understanding star formation is one key in our efforts to understand the Universe we live in. One main obstacle hindering progress is that our information on the raw material of stars—interstellar gas—can only be viewed projected in two dimensions, in the plane of the sky. This stops us from accessing one of the most fundamental quantities linked to star formation: the volume density of the gas.However, the Gaia satellite data can induce a leap forward: for the first time, we can systematically access the true, 3-dimensional (3D) structure of the interstellar medium (ISM). This also provides a new opportunity to access the volume density structure of the gas. We have recently made strong contributions in i) using Gaia data to derive and analyse the 3D structure of the ISM, and ii) developing inverse modelling techniques to approximate the 3D structure of star-forming clouds. Together, these two approaches can unlock the access to the volume density statistics across the entire range of densities relevant for star formation. We propose a project that will derive unprecedented, wide-dynamic-range information on the volume density distribution of the star-forming ISM. Such information is currently crucially missing and not obtainable via traditional techniques. By providing it, we will derive unique constraints for the current, gravoturbulent star formation framework and analytic star formation rate models. For this, we propose a 3-year project for a postdoc and the PI.