I am an astrophysicist currently working at the University of Bonn
My topic of predilection is the physics of galaxy clusters. Clusters are the largest and most massive building blocks of the Universe, made up of hundreds to thousands of galaxies, embedded in a large halo of hot plasma. But their total mass is actually dominated by dark matter, a mysterious constituent which does not interact with light.
In my work, I try to answer a number of fascinating questions about these cosmic structures: how they were formed, what they are made of, or what they can teach us about the nature and content of our Universe.
In this purpose, I take part in large surveys of the extragalactic skys in the X-ray waveband, in which the hot gas that permeates clusters glow. I have a leading role in the XXL survey, the largest contiguous X-ray survey undertaken by ESA's XMM satellite, and I am actively involved in SRG/eROSITA, a German/Russian mission to perform the next generation X-ray all sky survey (start scheduled in 2019). In such surveys, one can detect new, large samples of galaxy clusters to study their properties in an unbiased way, and use the mass and space distribution of galaxy clusters to gain insights on the underlying cosmological models.
For a fresh perspective, I also take part in the ESA Euclid mission, which will permit to detect and study galaxy clusters from the optical emission of their galaxies in a large survey and measure their total masses using graviationnal lensing effects.
Aside from surveys, I investigate the physics of galaxy clusters by means of detailed multi-wavelength follow-up programs of representative sub-samples. Examples of such projects are eeHIFLUGCS (which focuses on the ~380 X-ray brightest clusters in the sky) and APEX-SZ (a combined lensing/X-ray/millimeter study of ~30 clusters). In the future, I also hope to study the galaxy clusters discovered in all those large surveys using ESA's next X-ray observatory, Athena, planned for 2028.