Speaker
Prof.
roberto mignani
(INAF/IASF)
Description
RX J1856.5-3754 is a radio-quiet Isolated Neutron Stars (INSs) discovered in the soft X-rays through its purely thermal surface emission. Owing to its large inferred magnetic field of ∼1013 G, radiation from its surface is expected to be substantially polarised, independently on the mechanism actually responsible for the thermal emission. A large observed polarisation degree is, however, expected only if quantum-electrodynamics (QED) polarisation effects are present in the magnetised vacuum around the star. In this talk, I will report on the measurement of optical linear polarisation for RX J1856.5-3754 (V∼25.5) with the Very Large Telescope. We measured a polarisation degree P.D.=16.43%±5.26%, large enough to support the presence of vacuum birefringence, as predicted by QED.
Primary author
Prof.
roberto mignani
(INAF/IASF)
