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Accueil > Séminaires

Roberto Mignani

Measuring the polarisation from the thermal radiation from an isolated neutron stars can unveil QED effects

jeudi 16 novembre 2017, 14h

salle de conférences de l’observatoire


INAF - Istituto di Astrofisica Spaziale e Fisica Cosmica Milano, via E. Bassini 15, 20133, Milano (Italie)
Janusz Gil Institute of Astronomy, University of Zielona Góra, Lubuska 2, 65-265, Zielona Góra, (Pologne)

Résumé :

Neutron Stars (INSs) can be detected thanks to thermal soft X-ray/optical/UV radiation from their hot surface (105-106 K). Owing to their large inferred
magnetic field (up to 1013-15 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 quantumelectrodynamics
(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 the isolated neutron star RX J1856.5-3754 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.

Référence :
R. P. Mignani V. Testa D. González Caniulef R. Taverna R. Turolla S. Zane K. Wu
Evidence for vacuum birefringence from the first optical-polarimetry measurement of the isolated neutron star RX J1856.5−3754
Monthly Notices of the Royal Astronomical Society, Volume 465, Issue 1, 11 February 2017, Pages 492–500

Voir en ligne : Communiqué de presse de l’Observatoire Européen Austral (ESO)