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High Energy Cosmic Rays

High Energy Cosmic Rays. Eli Waxman Weizmann Institute, ISRAEL. Cosmic ray flux and Composition. log [dJ/dE]. E -2.7. Galactic. Protons. E -3. X-Galactic (?). Heavy Nuclei. Lighter. Galactic plane enhancement. Isotropy. 1. 10 6. 10 10. E [GeV]. U cr (1GeV)=1 eV/cm 3.

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High Energy Cosmic Rays

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  1. High Energy Cosmic Rays Eli Waxman Weizmann Institute, ISRAEL

  2. Cosmic ray flux and Composition log [dJ/dE] E-2.7 Galactic Protons E-3 X-Galactic (?) Heavy Nuclei Lighter Galactic plane enhancement Isotropy 1 106 1010 E [GeV] Ucr(1GeV)=1 eV/cm3 [Blandford & Eichler, Phys. Rep. 87; Axford, ApJS 94; Bird et al. 94; Nagano & Watson, Rev. Mod. Phys. 00; Abu-Zayyad et al. 01]

  3. Composition Fly’s Eye HiRes/MIA [Abu-Zayyad et al. 01] [Bird et al. 94]

  4. Acceleration Problem [K. Arisaka 02]

  5. X-Galactic Ultra High Energy p • High energy, XG n sources exist pg (pN) p’s ne’s, nm’s • UHE p flux Handle on n flux, detector size • Prime n telescope motivation: Identify UHE p source(s)

  6. The Data

  7. Data- Calibrated at 1019eV

  8. [EW 95] Model • Fly’s Eye fit for Galactic heavy (<1019eV): JG~E-3.50 • X-Galactic protons: Generation spectrum (shock acceleration): Generation rate(GRB motivated): Redshift evolution ~ SFR (GRB motivated).

  9. [Bahcall & EW 02] Model vs. Data X-G Model: Ruled out 7s

  10. Data/Model consistency • Define: • 1019eV to 1020eV: Data (YK,AG,FE,HR) and model consistent with XG protons, + GZK

  11. Conclusions are Robust

  12. A note on GRBs • Energy generation rate: • Proton acceleration: Ep,max ~ 1021 eV Claims for Ep,max << 1021 eV - irrelevant for the model (May be valid for “external shocks” only) • For more: See talk by P. Meszaros and Lec. Notes Phys. review (astro-ph/0103186) [Frail et al. 01; Schmidt 01]

  13. Summary • Yakutsk, Fly’s Eye, HiRes: Consistent with XG protons: + GZK (Robust; Consistent with GRB model predictions [see talk by P. Meszaros]) • AGASA (25% of total exposure): Consistent below 1020eV Excess above 1020eV: 2.2+/-0.8 8 observed New source/ New physics/ 25% energy Local inhomogeneity over-estimate • Need: Hybrid 1018eV to 1020eV observations ??

  14. Implications for n telescopes • X-Galactic sources of high energy n’s are out there • UHE p flux constrains expected n flux ~ 1 km3 scale required at 1 to 103 TeV energies >> 1 km3 required at >>103 TeV (see J. Bahcall’s talk)

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