Pantheon SEMPARIS Le serveur des séminaires parisiens Paris

Statut Confirmé
Série APC-COLLOQUIUM
Domaines astro-ph
Date Vendredi 7 Décembre 2018
Heure 11:00
Institut APC
Salle TBA
Nom de l'orateur Kachelriess
Prenom de l'orateur Michael
Addresse email de l'orateur
Institution de l'orateur Trondheim, Norway
Titre A Fresh Look at Galactic Cosmic Rays
Résumé The increased precision of new cosmic ray (CR) experiments has revealed several observational anomalies, i.e. deviations from the ``naive'' expectations in the diffusion picture for CR propagation. After reviewing a more theoretical challenge for the simplest diffusion picture, I argue that CRs diffuse strongly anisotropic. As a result, the number of CRs sources contributing to the locally observed flux is strongly suppressed, and few local CR source may dominate the CR flux. In particular, I show that the 2-3 Myr old source required to explain the Fe60 sediments found in Earth's ocean crust can also explain naturally the "positron excess" as well as the observed breaks at 200 GV in the CR primary spectra. At higher energies, Vela may be responsible for the CR knee and the CR flux up to the transition to extragalactic CRs.
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