Speaker
Description
Cosmic rays (CRs) are accelerated in the Galaxy up to energies of at least a few petaelectronvolts (1 PeV = 1e15 eV), as indicated by the detection of gamma-rays well above 10 TeV from various sources in the recent years. This implies the presence of a PeVatron source population in our galaxy, accelerating CRs to PeV energies. The astrophysical nature of these objects, however, is still unclear. One proposed candidate are young massive star clusters, which might accelerate particles at the shocks created by their stellar winds and supernovae. This idea is backed up by the detection of the stellar clusters Westerlund 1 (Wd 1), Westerlund 2, Cygnus OB2 and the superbubble 30 Doradus in very-high-energy gamma-rays. Nevertheless, an unambiguous identification of these sources as PeVatrons requires X-ray observations, too, which could confirm them as particle accelerator via the detection of synchrotron radiation. Additionally, synchrotron X-rays would help to identify the gamma-ray emission scenario, i.e., leptonic via inverse Compton radiation or hadronic via pion decay, by providing information on the source‘s magnetic field. For my Master‘s thesis, I analyze X-ray data from the first four all-sky surveys of the eROSITA telescope around Wd 1 to search for nonthermal X-ray synchrotron emission, thus adding to the evidence for Wd 1 being a PeVatron.
