Ever-changing dust: unveiling dust properties across galactic environments

• Applicant: Dr. Svitlana Zhukovska
• Subject Area: Astrophysics and Astronomy
• Term: from 2011 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 203268975

Interstellar dust is an ubiquitous component of the ISM playing an active role in shaping its physical and chemical structure from the earliest evolution of galaxies. A detailed understanding of dust properties as a function of environment is therefore required. This is the main goal of this project. We will address this problem on several galactic scales:I) Interstellar dust properties demonstrate small scale variations which reflect a complex interplay between dust formation and destruction processes. The efficiencies of these processes depend on the local physical conditions in the ISM and matter cycle between dense molecular clouds and diffuse intercloud gas. To understand the variations of grain properties, we need to combine a dust model that captures dust formation and destruction processes, with a realistic model of the ISM evolution. State-of-the-art numerical simulations of the lifecycle of molecular clouds within the SILCC project suit ideally to our purpose as they include all necessary processes to model the physical and chemical structure of the ISM. They have sufficient resolution allowing us to study dust destruction by supernova shocks in the inhomogeneous ISM. Upon implementing and testing the detailed model of dust evolution in the ISM, we will explore the physical conditions at which most gas species accrete on grain surfaces. The synthetic distribution of element depletions with gas density predicted by the models will be compared with the interstellar depletions measured in different sightlines in our galaxy. The details of dust re-formation in the ISM are still unclear. Such a comparison can provide an important constraint for this process.II) On the larger scale, we will focus on the spatial and temporal variations of the dust content in extragalactic systems. The averaged dust properties are governed by global galactic evolution processes such as star formation, infall and galactic winds. Our preliminary work showed that these processes are responsible for the transition to dust production dominated by dust growth in the ISM leading to drastic changes in the dust content of a galaxy. We will investigate how this transition affects the evolution of young massive galaxies in starburst and post-starburst stages in the young Universe. We will also model the dust evolution in local, much better studied star-forming galaxies, to understand what clues to the interstellar matter cycle are hidden in the observed variations in the dust-to-gas ratio.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1573: Physics of the Interstellar Medium
• Participating Person: Dr. Cornelia Jäger