Quantifying ISM Turbulence in Nearby Galaxies on 100 pc Scales

• Applicant: Dr. Fabian Walter
• Subject Area: Astrophysics and Astronomy
• Term: from 2011 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 203332114

The origin of interstellar turbulence has been a puzzle for decades. Investigating the possible mechanisms that drive the turbulence in the interstellar medium (ISM) of galaxies on scales of giant atomic complexes (∼100 pc) and below are the focus of numerous theoretical studies and lies at the heart of the newly installed ISM–SPP. However, even though turbulence is a fundamental property of the ISM that needs to be modeled, there is a clear lack of observational data to constrain turbulence in a representative sample of nearby galaxies on the spatial scales of interest. The goal of this project is in principle simple: to measure interstellar turbulence and its dependence on local environment on scales of ∼100pc, capitalizing on (a) three newly available state–of–the–art large VLA HI surveys of nearby galaxies (totaling more than 100 galaxies with exquisite available HI data), (b) newly developed mapping routines that greatly enhance the dynamic range in radio interferometric imaging, critically needed for the proposed analysis and (c) a sophisticated toolbox that is needed to go beyond previous turbulence studies. The PI has contributed significantly to the groundwork needed for this analysis (points a–c) and requests 3 years of funding for one PhD position for this project. The results of this study, quantifying turbulence on 100 pc scales reliably in a large sample of more than 100 extragalactic environments, will be of direct relevance to many ongoing theoretical and numerical ISM studies within the ISM–SPP.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1573: Physics of the Interstellar Medium