Cosmic-ray Astrochemistry
Emmy Noether Group
We are currently hiring
There is an on-going open call for a 2+(2) postdoctoral researcher in theoretical astrochemistry! The group is looking for an enthusiastic researcher with experience in quantum chemical methods and/or molecular dynamics to investigate the atomic-scale processes following cosmic ray interactions with icy astrophysical grains.
Job ad: AAS Jobregister | UDE
We will also be hiring 2 PhD students to start in 2027: one around March 2027, and the other in Autumn 2027.
Cosmic ray astrochemistry
from atomic to astrophysical scales
This is the group page for the AG Gaches Emmy Noether page hosted in the Faculty of Physics at the University of Duisburg-Essen. Our group focuses on studying the role of energetic particles, dubbed cosmic rays, from the atomic to astrophysical scales. The research we conduct is interdisciplinary, including theoretical chemistry, computational astrophysics, and astrochemical modeling, to unify our knowledge from the micron to parsec scales.
See our official UDE group page for more info.
RESEARCH HIGHLIGHTS
Resolving Dense Photo-dissociation Regions in 3D
Research carried out by PI Dr. Brandt Gaches in collaboration with UDE and Zhejiang Laboratory researchers
Dense photo-dissociation regions are regions where the ultraviolet radiation from massive stars is impinging upon nearby (often nascent) molecular gas. These regions produce a lot of important observational diagnostics for understanding star formation both locally in the Milky Way and in other galaxies. The Orion Bar is the archetypal example. Previous models have predominantly been one-dimensional slabs with sophisticated chemistry and radiation transfer.
Using new improvements in 3D-PDR done at UDE, we have performed the first fully resolved 3D models of such regions. The new models include a full treatment of the rovibrational levels of molecular hydrogen, providing important predictive power for JWST. In our first paper, we examined the structure of the photodissociation front, and the locations of the H2 dissociation (red) and C+ recombination (blue) fronts with respect to each other. Our models are able to accurately reproduce the observations of these locations, the column densities of most molecules, and the emission features observed by JWST.
Appeared in A&A, October 2026
Paper: A&A | arXiv
Press release: UDE
Searching for Prebiotics in Protoplanetary disk V883 Ori
Research carried out by PhD student Abubakar Fadul while at the Max Planck Institute for Astronomy, with Dr. Kamber Schwarz
Complex organic molecules (COMs), typically defined as carbon-bearing species with six or more atoms, have been widely detected in space. A subclass of these, known as prebiotic molecules, are thought to play a key role in the formation of life. We report the first tentative detection of two such prebiotic precursors (ethylene glycol and glycolonitrile) in a protoplanetary disk. These molecules are considered potential precursors to sugars and amino acids, fundamental building blocks of life. Our findings suggest that complex organic molecules are inherited from earlier stages of star formation and continue to evolve during the disk phase. This supports the idea that the chemical conditions necessary for life may be widespread in the Universe, making the emergence of life more universal than previously thought.
Appeared in ApJL, August 2025
Paper: ADS | arXiv
Press release: MPIA Press Office
Analytic Estimation of Attenuating Column Densities
Research carried out by PI Dr. Brandt Gaches
A parameter of key importance in astrochemical models is the column density of gas that attenuates the external radiation field. In complex simulations, this can be computed using expensive raytracing schemes, while for one-zone (0D) or one-dimensional chemical models, it is provided as an input. In the paper, I present an entirely analytic model to estimate the average attenuating column density expected as a function of gas density. The model assumes a hierarchical turbulent cloud undergoing gravitational collapse. The analytic form is able to reasonably-well reproduce the average fitted trends found from previous suites of three-dimensional simulations. The model can be utilized to provide more robust constraints on this parameter in astrochemical modeling, rather than leaving it as a purely free parameter. The figure compares a fiducial model for the solar neighborhood (and the components) with the 3D model fits (red).
Appeared in A&A Letters, August 2025
Paper: ADS | arXiv
Meet the Team
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Brandt A. L. Gaches
Group leader, MC 364
brandt.gaches(at)uni-due.de -
Manuela Adam-Skowranek
Sekretariat, MC 367
manuela.adam(at)uni-due.de -
Abubakar Fadul
PhD student. Post-processing of star-formation simulations with astrochemical networks. Observations of organics in protostellar disks.
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Arghyadeb Roy
Research assistant, Indian Institute of Science Education and Research Kolkata. Investigating the radiation signatures and diagnostics of cosmic-ray induced chemistry.
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Fynn Wawrzyniak
Master’s student. Accretion physics of massive protostars.
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Nils Wolfsdorff
Bachelor’s student. Analysis of observations of an X-ray irradiated cloud.
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Bengisu Kırtaş
Erasmus+ intern. Analysis of observational radio interferometer data.
Interesting in Joining?
We are always looking for motivated Bachelor’s and Master’s students who are interested in astrochemistry, cosmic ray physics, and star formation! This includes students with primary interests in physics or chemistry, with possible projects ranging from theoretical chemistry investigations of electron-impact physics, astrochemical modeling of molecular clouds, and analyzing magneto-hydrodynamic simulations or data from the James Webb Space Telescope. Interested students should feel free to send me an email!
The group can also act as a host for postdoctoral fellowships. In particular, I would be willing to support and help interested postdoc candidates to apply for independent funding to join the group, such as a Humboldt postdoctoral fellowship, a DFG Walter Benjamin fellowship, or an EU Marie Curie fellowship.
Current in-office coffee
Concept Coffee Roasters
Columbia Catura, experimental processing, co-fermentation
Kmen Coffee Roasters
Burundi Red Bourbon, washed processing
Science is funded by coffee. more coffee, more science!
Acknowledgements
The group is funded by the Deutsche Forschungsgemeinschaft (DFG) Emmy Noether grant #542802847. We also receive support from Zulip in the form of an upgraded channel for the group.
