I am professor for theoretical astrophysics at Heidelberg University. My research activities focus on the formation of stars at present days and in the early universe, on the dynamics of the interstellar medium, on astrophysical turbulence, and on the development of numerical methods for computational astrophysics.

For an overview of my curriculum vitae follow this LINK.

For my website at the Center for Astronomy at Heidelberg University follow this LINK.

I recently received an ERC synergy grant together with Patrick Hennebelle (CEA, Saclay), Sergio Molinari (INAF, Rome), and Leonardo Testi (ESO, Garching). More information is found on this LINK.

Current Research Highlight

Januar 2021: Magnetic fields in star-forming systems – II: Examining dust polarization, the Zeeman effect, and the Faraday rotation measure as magnetic field tracers

Reissl, Stefan; Stutz, Amelia M.; Klessen, Ralf S.; Seifried, Daniel; Walch, Stefanie: MNRAS, 500, 153 – 176 (2021) [ADS link]

Kinked magnetic field lines (blue) and the corresponding iso-surface contours (red) of the gas distribution of a filament in a SILCC-Zoom simulation. Yellow dots indicate regions of star formation (from Reissl et al. 2021, MNRAS, 500, 153).

The degree to which the formation and evolution of clouds and filaments in the interstellar medium is regulated by magnetic fields remains an open question. Yet the fundamental properties of the fields (strength and 3D morphology) are not readily observable. We investigate the potential for recovering magnetic field information from dust polarization, the Zeeman effect, and the Faraday rotation measure (RM) in a SILCC-Zoom magnetohydrodynamic (MHD) filament simulation. The object is analysed at the onset of star formation and it is characterized by a line-mass of about (M/L) ∼ 63 M pc−1 out to a radius of 1 pc and a kinked 3D magnetic field morphology. We generate synthetic observations via POLARIS radiative transfer (RT) post-processing and compare with an analytical model of helical or kinked field morphology to help interpreting the inferred observational signatures. We show that the tracer signals originate close to the filament spine. We find regions along the filament where the angular dependence with the line of sight (LOS) is the dominant factor and dust polarization may trace the underlying kinked magnetic field morphology. We also find that reversals in the recovered magnetic field direction are not unambiguously associated to any particular morphology. Other physical parameters, such as density or temperature, are relevant and sometimes dominant compared to the magnetic field structure in modulating the observed signal. We demonstrate that the Zeeman effect and the RM recover the line-of-sight magnetic field strength to within a factor 2.1-3.4. We conclude that the magnetic field morphology may not be unambiguously determined in low-mass systems by observations of dust polarization, Zeeman effect, or RM, whereas the field strengths can be reliably recovered.

Earlier Research Highlights

For the all monthly research highlights follow this LINK.

Funding Sources