University of Maryland
Atlantic Building, Room 2400
4:30 PM Monday, September 10, 2012
Coffee, Tea & Snacks 4:15-4:30 PM

Vladimir Ptuskin
Origin and Propagation of Ultrahigh Energy Cosmic Rays

Origin of cosmic rays with the highest detected energies up to more than 1020 eV is discussed. The acceleration of these particles is associated with the most energetic extragalactic objects in the Universe – active galactic nuclei, gamma-ray bursts, magnetars, cosmological shocks, etc. Interactions with the background radiation in the intergalactic space change the composition of ultrahigh energy cosmic rays and lead to the suppression of their flux above about 5 1019 eV (the Greizen-Zatsepin-Kuzmin effect). The spectrum of ultrahigh energy cosmic rays produced by jets of active galactic nuclei is calculated.

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.