Hello,
I am professor for theoretical astrophysics at Heidelberg University working at the Institute for Theoretical Astrophysics (ITA) at the Center for Astronomy (ZAH). My research activities focus on the formation of stars at present days and inthe early universe, on the dynamics of the interstellar medium, on astrophysical turbulence, and on the development of numerical methods for computational astrophysics including advanced machine learning.
My ORCID number is 0000-0002-0560-3172.
For an overview of my curriculum vitae follow this LINK.
For a current list of publications click this LINK to ADS to ADS or this LINK to google scholar.
For my website at the Center for Astronomy at Heidelberg University follow this LINK.
In 2020, I 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.
Currently, I am member of the 2024/25 Class of Fellows at the Radcliffe Institute for Advanced Studies at Harvard University and guest at the Harvard-Smithsonian Center for Astrophysics during my sabbatical at Harvard University.
Current Research Highlight
June 2025: The spectrum of magnetized turbulence in the interstellar medium
Beattie, James R., Federrath, Christoph, Klessen, Ralf S., Cielo, Salvatore, Bhattacharjee, Amitava: Nature Astronomy (2025) [Nature Astronomy link]
Two-dimensional slice of the 10,0803 simulation showing the logarithmic magnitude of the current density (top), mass density (bottom) and magnetic field lines sliced on the plane (right; white), where the subscript zero indicates the volume average. Fractal current sheets, shown in red in the top left of the figure, are strongly correlated with the densest regions, shown in yellow in the bottom left of the figure, accompanied by tightly coiled magnetic fields.
The interstellar medium (ISM) of our Galaxy is magnetized, compressible and turbulent, influencing many key ISM properties, such as star formation, cosmic-ray transport, and metal and phase mixing. Yet, basic statistics describing compressible, magnetized turbulence remain uncertain. Utilizing grid resolutions up to 10,0803 cells, we simulated highly compressible, magnetized ISM-style turbulence with a magnetic field maintained by a small-scale dynamo. We measured two coexisting kinetic energy cascades, Ekin(k ) ∝k−n, in the turbulence, separating the plasma into scales that are non-locally interacting, supersonic and weakly magnetized (n = 2.01 ± 0.03 ≈ 2) and locally interacting, subsonic and highly magnetized (n = 1.465 ± 0.002 ≈ 3/2), where k is the wavenumber. We show that the 3/2 spectrum can be explained with scale-dependent kinetic energy fluxes and velocity-magnetic field alignment. On the highly magnetized modes, the magnetic energy spectrum forms a local cascade (n = 1.798 ± 0.001 ≈ 9/5), deviating from any known ab initio theory. With a new generation of radio telescopes coming online, these results provide a means to directly test if the ISM in our Galaxy is maintained by the compressible turbulent motions from within it.
Earlier Research Highlights
For the all monthly research highlights follow this LINK.
Funding Sources
