Speaker
Description
The soft X-ray telescope eROSITA aboard the Spectrum-Roentgen-Gamma (SRG) mission is the first located in a halo orbit around the Sun-Earth L2 Lagrangian Point. With its main scientific goal to find 100000 clusters of galaxies for cosmological studies detailed knowledge of the background is crucial to be able to distiniguish faint extended objects from point-like sources and to determine signficantly the corresponding source parameters.
We give a detailed report what has been learned from the SRG/eROSITA mission so far in the context of particle background at L2. We summarize the various hits by micro-meteoroids. We show the temporal variability of the galactic cosmic-ray background with the solar cycle. The spectral behaviour has been derived from "Filter Wheel Closed" exposures. Solar activity affects eROSITA via flares and coronal mass ejections. Solar wind charge exchange did only play a minor role (in particular in the first all-sky survey eRASS1) compared with ROSAT or XMM-Newton missions.
Pre-launch background estimates were initially exceeded by in-flight background levels but could later be explained and brought in-line with the measurements by improved simulations as well as better event flagging. Finally we show results from the analysis of individual particle pattern tracks obtained in "MIP rejection off" exposures and in simulations.
