Faraday Synthesis and Magnetic Field Statistics

• Applicant: Privatdozent Dr. Torsten Enßlin
• Subject Area: Astrophysics and Astronomy
• Term: from 2010 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 108727618

Magnetic structures in the interstellar and intergalactic medium imprint characteristic signatures onto polarised synchrotron radiation. Two processes are relevant here, the emission process, which depends on the strength and orientation of the magnetic field, and the Faraday rotation, which is determined by the magnetic line-of-sight component. Both permit deductions on the three dimensional structure of magnetic fields. As planned, we have developed during the first funding period methods to extract from radio observations information on cosmic magnetism. These should be extended and applied to data sets of the research unit. On the one hand, there is our novel Faraday synthesis, the unification of RM and aperture synthesis. This delivers high fidelity three dimensional images of cosmic magnetic fields. On the other hand, we have developed methods for the statistical characterization of magnetic fields to measure magnetic helicity or to indicate magnetic reversals with respect to the line-of-sight, the latter via the Faraday caustics that we have predicted. We strive now for a unification of the statistical analysis and the imaging algorithms. A special Faraday synthesis method should be developed for the Faraday caustics. Furthermore, we want to develop and apply novel methods to map out galactic and extragalactic magnetic fields via Faraday rotation data.

• DFG Programme: Research Units
• Subproject of: FOR 1254: Magnetisation of Interstellar and Intergalactic Media: The Prospects of Low-Frequency Radio Observations
• Participating Person: Professor Marcus Brüggen, Ph.D.