Understanding modern radioastronomical observations via advanced numerical simulations

• Applicant: Professor Dr. Jörg Büchner
• Subject Area: Astrophysics and Astronomy
• Term: since 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 431893099

Astronomical observations witness a wave of blossom by new radio-telescopes with unprecedented resolution, sensitivity, cadence like OCSCARS and ALMA. The new instruments provide data at a qualitatively higher level which allow, in principle, to constrain models of plasma-processes in the Universe much better than before. To utilize this information also new, more quantitative models of astrophysical plasma-, wave-emission and - propagation processes are needed. The new generation of models should describe the chain of processes starting from the energy sources towards predicting the signals, detectable at Earth. Detectable radio waves are caused by micro-physical mechanisms. The macroscopic energy sources have to be considered first at large scales, then the transfer of energy towards kinetic scales has to be decribed as well as radiation processes – either direct or those requiring plasma instabilities. The emissions have to be derived for the entire emitting volumes and their propagation to the radio antenna has to be taken into account as well as instrument effects.We plan to consider all parts of this chain of processes starting from magnetic reconnection, releasing magnetic energy at large scales, to the formation of observable coherent radio waves. We focus on coherent emissions first due to solar eruptions - for which the most detailed is information is available to constrain theoretical models and on coherent radio waves emitted by pulsars (ALMA observations). The full treatment of all aspects of the formation of the observable radio-signals requires capacities and experience which lead beyond the abilities of one single group of researchers. We therefore plan carry out our investigations in close collaboration between our groups with their complementary background and expertise: on the German side the research group SMART that continues the work of the former TSSSP group of the MPS Göttingen now at the TU Berlin with its long-term experience in kinetic, hybrid-, Vlasov-, PIC-code HPC-plasma- as well as MHD simulations in close collaboration with the astrophysicists of the Center for Astronomy and Astrophysics of the Berlin Institute of Technology (TU) and the radio-astronomy group of the Astronomical Institute of Czech Academy of Sciences at Ondrejov that has acquired expertise in multi-scale MHD modeling necessary for assembling the total radio emissivity and its significant expertise in radio/mm wave data analyses including the development and data use of own instruments as well as of ALMA, hosting one of the nodes of the European Regional ALMA Center.Combining the expertise of the two groups will allow us to further develop and utilize all necessary tools to better understand observed coherent radio emissions of solar eruptions and of pulsars utilizing advanced numerical simulation methods for understanding modernradio-astronomical data.

• DFG Programme: Research Grants
• International Connection: Czech Republic
• Partner Organisation: Czech Science Foundation
• Co-Investigator: Professor Dr. Dieter Breitschwerdt
• Cooperation Partner: Dr. Miroslav Barta