Speaker
Description
Highly magnetised isolated neutron stars are amongst the most interesting and exotic objects observable in our sky. X-ray polarisation carries information about the physics occurring in the extreme environments surrounding these sources that is otherwise inaccessible to us. In particular, magnetars and X-ray Dim Isolated Neutron Stars (XDINSs) may be key to finally probing vacuum birefringence, a quantum electro-dynamics (QED) effect that has long been predicted but never tested. Mode conversion at the QED vacuum resonance in a magnetised atmosphere, alongside additional effects such as particle bombardment and partial ionisation, can leave significant imprints on the polarisation signature of thermal emission, while remaining otherwise unidentifiable in the overall spectrum. With the continued success of Imaging X-ray Polarimetry Explorer (IXPE) and the ongoing development of new polarimetric telescopes (e.g. REDSoX / GOSoX, eXTP), a new age of X-ray exploration has begun. Future facilities such as eXTP, GOSoX and NewAthena will provide invaluable information. Combining the polarimetric capabilities of the former with the effective area and energy resolution of the latter will allow us to accurately reconstruct emission maps and the complex magnetic field topology of these sources, opening new avenues for scientific discovery.
