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Accueil > Séminaires > Archive des séminaires d’Utinam > 2017

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

Roberto MIGNANI

INAF - Istituto di Astrofisica Spaziale e Fisica Cosmica Milano, via E. Bassini 15, 20133, Milano (Italie)
et
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)