DEPARTMENT OF PHYSICS DISSERTATION DEFENSE - Josephine Wong

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Title: 

Studying Pulsar Wind Nebulae with the Imaging X-ray Polarimetry Explorer

Abstract: 

Pulsar wind nebulae (PWNe) are magnetized bubbles of relativistic particles powered by young, rapidly rotating neutron stars, often encased within a supernova remnant (SNR) shell. These Galactic PeVatrons provide a window to study extreme particle acceleration and relativistic shocks at conditions not reproducible on Earth. In the X-rays, they primarily emit synchrotron radiation, which can be highly linearly polarized, revealing average magnetic field orientations. Some nearby, bright PWNe are spatially resolved, making them ideal targets for the Imaging X-ray Polarimetry Explorer (IXPE), the first dedicated X-ray polarization mission. In this talk, I will describe IXPE’s findings on the Crab Nebula and SNR Kes 75. Applying a novel technique to separate the pulsar and the nebula polarization components, I demonstrate how we have used IXPE to map the large-scale magnetic field structure in the Crab Nebula and to measure the pulsar’s phase-varying polarization. I also describe an indication of temporal variability from Kes 75’s high-field pulsar, unusual for a rotation-powered pulsar, and how X-ray polarization can probe links between rotation-powered pulsars and magnetars. Lastly, I will discuss main highlights from IXPE’s study of MSH 15-52, SNR B0540-69, and 3C 58.