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T: Teilchenphysik

T 301: Kosmische Strahlung III

T 301.4: Vortrag

Dienstag, 19. März 2002, 15:15–15:30, HS 19

Probing IR Background by e^± Pair Halos — •Anant Eungwanichayapant — Max-Planck-Institut für Kernphysik, D-69029 Heidelberg, Germany

A model of e^± pair halos and the first results from a Monte Carlo simulation of this model are presented. A large number of e^± pairs are produced by electromagnetic cascades initiated by very high energy gamma photons from AGNs (E_γ ≥ 10¹³ eV) interacting with intergalactic radiation fields such as the 2.7 K microwave background radiation (MBR) and infrared (IR) background photon field. If intergalactic magnetic fields are strong enough (B > 10⁻⁹ G) the e^±s are immediately isotropized and trapped in a certain region. Therefore the e^± pairs will form a huge halo (R ≈ 10 Mpc) around the AGNs and produce a flux of gamma photons (E_γ > 10¹¹ eV) potentially visible for next-generation ground based Cherenkov telescopes. The energy spectrum and angular distribution of the gamma rays of the halo can be used to probe the spectrum of IR background at different redshift.