Contributed Talk - Splinter JungeAG

Monday, 12 September 2022, 16:30   (SFG 1010 / virtual JAG)

Searching for Cooling Neutron Stars in Data of the X-ray Observatory SRG/eROSITA

Elias Ehl, Prof. Dr. Werner Becker
Max-Planck Institut für extraterrestrische Physik

The eROSITA all-sky survey provides a unique opportunity to search for X-ray counterparts of all known radio pulsars. It has a much higher sensitivity compared to the ROSAT survey and the coverage of objects previously unobserved by XMM/Chandra is significant. Today, only about 3300 rotation-powered neutron stars which are observable as pulsars are known. About half of those are accessible to us in the data of the X-ray observatory eROSITA. The observation of the thermal emission of rotation powered pulsars allows us to measure the surface temperature and the size of the emitting area from their X-ray spectra. Together with the pulsars' spin-down age this allows us to study their thermal evolution by comparing the measured surface temperatures or upper limits with theoretical neutron star cooling models, computed for various equation of states of nuclear matter. We thus infer the EOS model that fits best to the data. The possibility of altered hadronic interactions, the existence of stable pions, kaons, hyperons or free quarks in the core of a neutron star and the influence of superfluid neutrons in the inner crust all yield different cooling rates and therefore theoretical predictions, so that the neutron star surface temperature as a function of the neutron star age reflects the stellar composition. In my talk I will report on my master thesis research project which I started in April 2022 under the supervision of Prof. Werner Becker at the Max-Planck Institut of extraterr. Physik in Garching.