Protostellare Ausflüsse und Interstellare Turbulenz

• Applicant: Professor Ralf Klessen, Ph.D.
• Subject Area: Astrophysics and Astronomy
• Term: from 2004 to 2011
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5440931

• Final Report Year: 2011

Final Report Abstract

In the project Protostellar Outflows and Interstellar Turbulence we have addressed the question of whether protostellar outflows can drive supersonic interstellar turbulence. We have performed a set of dedicated 2D simulations, which demonstrated that a single jet cannot drive turbulence that becomes volume-filling and supersonic. This is in contradiction to other recent claims in the literature and is probably due to the fact that these studies considered multiple outflows, in self-gravitating clouds which are threaded by magnetic fields. We are currently following up on this line of reasoning as part of a diploma thesis. The numerical development necessary for this ongoing study has been laid by Robi Banerjee in the first part of the project. We have also been engaged in a series of colliding flow simulations to study molecular cloud formation in spiral arms In the second part, i.e. after Robi Banerjee had taken a position as head of an Emmy Noether Group, Simon Glover has been hired in the project. The scientific focus now shifted to the development of time-dependent chemical networks for astrophysical fluid dynamics and to the study of the dynamical evolution of the interstellar medium on larger scales, such as the formation of molecular clouds, the generation of synthetic maps for direct comparison with observational molecular line data, or the thorough analysis of the X-factor, the conversion factor from CO emission to total H2 mass. With several highly cited publication and with a number of follow-up grants that have been triggered by the research activities in the project , we think the project has been highly successful and scientifically fruitful. It has evolved considerably over the course of the years.

Publications

• “Can Protostellar Jets Drive Supersonic Turbulence in Molecular Clouds?”. 2007, The Astrophysical Journal, 668, 1028 – 1041
  Banerjee, R., Klessen, R. S., Fendt, C.
  
• “From the Warm Magnetized Atomic Medium to Molecular Clouds”. 2008, Astronomy & Astrophysics, 486, L43 – L46
  Hennebelle, P., Banerjee, R., Vázquez-Semadeni, E., Klessen, R. S., Audit, E.
  
• “The ISM in Spiral Galaxies: Can Cooling in Spiral Shocks Produce Molecular Clouds?”. 2008, Monthly Notices of the Royal Astronomical Society, 389, 1097 – 1110
  Dobbs, C. L., Glover, S. C. O., Clark, P. C., Klessen, R. S.
  
• “Clump morphology and evolution in MHD simulations of molecular cloud formation”. 2009, Monthly Notices of the Royal Astron. Soc., 398, 1082 – 1092
  Banerjee, R., Vázquez-Semadeni, E., Hennebelle, P., Klessen, R. S.
  
• “High- and Low-Mass Star Forming Regions from Hierarchical Gravitational Fragmentation”. 2009, The Astrophysical Journal, 707, 1023 – 1033
  Vázquez-Semadeni, E., Gómez, G. C., Jappsen, A.-K., Ballesteros-Paredes, J., Klessen, R. S.
  
• “Limiting Accretion onto Massive Stars by Fragmentation-Induced Starvation”. 2010, The Astrophysical Journal, 725, 134 – 145
  Peters, T., Klessen, R. S., Banerjee, R., Mac Low, M.-M.
  
• “Modelling CO Formation in the Turbulent Interstellar Medium”. 2010, Monthly Notices of the Royal Astron. Soc., 404, 2 – 29
  Glover, S. C. O., Federrath, C., Mac Low, M.-M., Klessen, R. S.