IRAP > Séminaires > Calendrier des séminaires > QED effects from the study of polarised light in isolated neutron stars

QED effects from the study of polarised light in isolated neutron stars

Séminaire le 15 juin 2017 de 11h00 à 12h00

Intervenant : Roberto Mignani

Salle Coriolis Salle Coriolis Observatoire Midi-Pyrénées - 14, avenue Edouard Belin - 31400 Toulouse

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RX J1856.5-3754 is an Isolated Neutron Stars (INSs) discovered in the soft X-rays through its purely thermal surface emission. Owing to its large inferred magnetic field of ∼10^13 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 briefly introduce the observational properties of isolated neutron stars and 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.

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