Axel studied physics and astronomy in Berlin. After German re-unification, he moved to the newly founded Leibniz Institute for Astrophysics Potsdam (AIP) where he works ever since. At the AIP, he is leading the X-ray astronomy group. He is heavily involved in the XMM-Newton Survey Science Centre and in the development of eROSITA, the main instrument on the Spektrum-Roentgen-Gamma mission. In the Athena universe, Axel is co-chairing the topical panel on the endpoints of stellar evolution.
His scientific nterests are widespread, ranging from the largest (clusters of galaxies) to the smallest X-ray emitting bodies (neutron stars) with a certain focus on white-dwarf accretors. Axel hopes that Athena will eventually be used to perform the arts of Doppler tomography at X-ray wavelengths.
Link to the PDF version.
Image: Doppler map and XMM-Newton X-ray light curve of the eclipsing polar HU Aqr.