Characterizing the acceleration and propagation of cosmic rays in Galactic pulsar wind nebulae and pulsar halos

• Applicant: Dr. Martin Georg Friedrich Mayer
• Subject Area: Astrophysics and Astronomy
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 539757922

The target of the proposed project is the investigation of the multiwavelength properties of the environments of Galactic rotation-powered pulsars, namely pulsar wind nebulae (PWNe) and diffuse pulsar halos. These objects are the manifestation of cosmic-ray electrons accelerated in pulsar winds propagating into their surroundings, and emitting across the whole electromagnetic spectrum via synchrotron radiation and inverse-Compton scattering. By modelling the combination of X-ray data from the all-sky survey of SRG/eROSITA, and (partly public) TeV to PeV gamma-ray information from the H.E.S.S., HAWC, and LHAASO observatories, we plan to constrain the physical properties controlling the phenomenology of pulsar environments.Key questions include the origin of the apparent slow-diffusion regions around middle-aged pulsars leading to the emergence of halos, as well as their low magnetic fields, evidenced by the lack of significant X-ray synchrotron emission in some objects. We will in detail study X-ray and gamma-ray properties of the evolved object Vela X, one of the closest PWNe to Earth, which currently appears to be transitioning into the halo regime. Furthermore, we will investigate the role of pulsars as Galactic particle accelerators and injectors of leptonic cosmic rays into the interstellar medium. This will be achieved by performing a systematic X-ray study of gamma-ray bright PWNe in the western Galactic hemisphere, and investigating typical magnetic fields, energy cutoffs, and particle injection efficiencies of the population as a whole.

• DFG Programme: WBP Position