Connecting core-collapse supernova remnants and their central neutron stars

Mayer, Martin Georg Friedrich (2023): Connecting core-collapse supernova remnants and their central neutron stars: an X-ray study using Chandra and SRG/eROSITA. Dissertation, LMU München: Fakultät für Physik

Abstract

The topic of this thesis is the investigation of core-collapse supernova remnants and their central neutron stars, with an emphasis on the intrinsic connection between the two. This is achieved via spectroscopic and astrometric analysis of their X-ray emission, which is characteristic for the hot plasma and energetic nonthermal processes occurring in these objects. On one hand, this work investigates the velocity distribution of central compact objects (CCOs), a class of neutron stars characterized by purely thermal emission. Via careful astrometric calibration of data from the Chandra X-ray telescope, it is shown that none of the investigated CCOs exhibits a problematically high velocity in the celestial plane, which would exceed the expectation for the recoil experienced by the neutron star during the explosion. Furthermore, the presented proper motion measurements are used, in combination with the expansion of the associated supernova remnants (SNRs), to constrain their ages in a model-independent manner. This allows dating the SNR Puppis A to an age of 4600 +/- 700 years, and establishing strict upper limits on the ages of the SNRs G350.1-0.3 and RX J1713.7-3946, at 700 and 1700 years, respectively. This is complimented by spectroscopic analysis of the X-ray emission of the SNRs Puppis A and Vela with physically motivated models, using data from the recently launched SRG/eROSITA telescope. In Puppis A, this allows for the identification of regions which were only recently shock-heated, as well as a detailed search for ejecta produced during the explosion. This reveals that Puppis A contains an atypically high fraction of silicon for a core-collapse SNR, as well as a misalignment of intermediate-mass elements with the recoil direction implied by the motion of the neutron star. Similarly, in the much older Vela SNR, an unexpected composition of X-ray detected ejecta is revealed, with strongly supersolar abundance ratios of neon and magnesium compared to oxygen. Furthermore, the presented analysis for the first time allows for isolating the hard synchrotron emission of the central Vela pulsar wind nebula from the softer thermal emission from the SNR. This effort demonstrates a much larger extent of the synchrotron nebula than visible at other wavelengths, at a radius up to three degrees. A possible explanation for its phenomenology is the slow diffusion of high-energy electrons through a relatively weak ambient magnetic field, similarly to the gamma-ray halos observed around several older pulsars.

• Dokumententyp: Dissertationen (Dissertation, LMU München)
• Keywords: Core-collapse supernovae, Supernova remnants, Neutron stars, X-rays
• Themengebiete: 500 Naturwissenschaften und Mathematik ; 500 Naturwissenschaften und Mathematik > 530 Physik
• Fakultäten: Fakultät für Physik
• Sprache der Hochschulschrift: Englisch
• Datum der mündlichen Prüfung: 4. April 2023
• 1. Bericht­erstatter:in: Becker, Werner