[Phys-seminars] 2017-06-07 Astrophysics and Cosmology Seminar

griv griv at bgu.ac.il
Mon Jun 5 11:02:41 IDT 2017

Astrophysics and Cosmology Seminar

 DATE: 07-06-17


 PLACE: Seminar Room 207, Building 54 (Physics)

On UHECR origin

Dr. Noemie Globus, Hebrew University of Jerusalem

Although their astrophysical sources remain a mystery, there is a lot to learn from the study of the transition between the Galactic cosmic rays, which dominate the flux up to energies around 10^18 eV, and the cosmic rays of extragalactic origin, at the highest energies. In the past few years new measurements (brought by experiments such as KASCADE-Grande, the Pierre Auger Observatory and Telescope Array) have radically improved our knowledge of the highest energy domain of the cosmic-ray spectrum. In this talk, I will show that the observational data across the Galactic to extragalactic cosmic-ray transition up to the highest energies can be described with minimal assumptions within a generic model putting together only one Galactic component and one extragalactic component. The key to the success of this model is that the protons emitted by the extragalactic sources have a different spectrum from the other types of nuclei, as we recently showed to be expected in highly magn
 etized and photon-rich environments. I will finally discuss multi-messenger constraints brought by neutrino and gamma-ray experiments, and show that our mixed-composition scenario is compatible with both the most recent Fermi-LAT measurements and with current IceCube limits.

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