Today I learned from Noemi Globus (NYU) That the Pierre Auger Observatory has an amazing result in cosmic-ray science: The cosmic rays at very high energy do not arrive isotropically at Earth but instead show a significant dipole in their arrival directions. As a reminder: At most energies, the magnetic field of the Galaxy randomizes their directions and they are statistically isotropic at the Earth.
The Auger result isn't new, but it is new to me. And it makes sense: At the very highest energies (above 1019 eV, apparently) the cosmic rays start to propagate more directly through the magnetic field, and preserve some of their original directional information. But the details are interesting, and Globus believes that she can explain the direction of this dipole from the local large-scale structure plus a model of the Milky Way magnetic field. That's cool! We discussed simulations of the local large-scale structure, and whether they do or can provide reasonable predictions of cosmic-ray production.
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