University of Maryland
Atlantic Building, Room 2400
4:30 PM Monday, October 31, 2011
Coffee, Tea & Snacks 4:15-4:30 PM

Peter Biermann
Max-Planck-Institute for Radioastronomy, Bonn, Germany
A Common Origin of Galactic and Extragalactic Cosmic Rays

The origin of cosmic rays at all energies is still uncertain. In this lecture we present and explore a model to produce cosmic rays with energy ranging up to 3×1020 eV. The model allows an explanation of a variety of recent data:

  1. an upturn in the CR-positron fraction (Pamela)
  2. an upturn in the CR-electron spectrum (ATIC, Fermi)
  3. a flat radio emission component near the Galactic Center (WMAP haze)
  4. a corresponding IC component in gamma rays (Fermi haze and Fermi bubble)
  5. the 511 keV annihilation line also near the Galactic Center (Pamela)
  6. an upturn in the CR-spectra of all elements from Helium, with a hint of an upturn for Hydrogen (CREAM)
  7. a flat γ-spectrum at the Galactic Center (Fermi)
  8. the cosmic ray spectrum from KASCADE, KASCADE-Grande, and Auger

We show here that just our Galaxy and the radio galaxy Cen A, each with their own galactic cosmic ray particles, but with those from the radio galaxy pushed up in energy by a relativistic shock in the jet emanating from the active black hole, are able to describe the most recent data.
Contrary to widely held expectations, no other extragalactic source population is required to explain the data, even at energies far below the general cutoff expected at 6×1019 eV, the Greisen-Zatsepin-Kuzmin turn-off due to interaction with the cosmological microwave background. We present several predictions for the detailed spectra, the cosmic ray composition and the propagation to Earth which can be tested in the near future.

Sponsored by: Department of Physics and the Institute for Physical Science and Technology, University of Maryland. For information call Catha Stewart at (301) 405-4811 or go to the UMD Space Physics group seminar web site.

There is free parking after 4:00 PM in lot B (the big parking garage across the street from the ATL building). There are a limited number of spaces in lot Q next to the new ATL wing with free parking after 4PM even when there is a basketball game on campus.