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High-energy limit of Galactic cosmic rays Vladimir Ptuskin IZMIRAN

High-energy limit of Galactic cosmic rays Vladimir Ptuskin IZMIRAN. CR Large Scale Experiments, 2011. J X E 3. knee. Galactic. extragalactic. black body suppression. Cosmic rays of Galactic origin: acceleration in supernova remnants and propagation in interstellar magnetic fields.

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High-energy limit of Galactic cosmic rays Vladimir Ptuskin IZMIRAN

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  1. High-energy limit of Galactic cosmic rays Vladimir Ptuskin IZMIRAN CR Large Scale Experiments, 2011

  2. JXE3 knee Galactic extragalactic black body suppression

  3. Cosmic rays of Galactic origin: acceleration in supernova remnants and propagation in interstellar magnetic fields VERITAS, MILAGRO

  4. basic diffusion model Ginzburg & Syrovatskii 1964, Berezinskii et al 1990, Strong & Moskalenko 1998 (GALPROP) H = 4 kpc, R = 20 kpc M51 ~ 15%of SN kinetic energy transfer to cosmic rays, Jcr(E)= Qcr(E)×Te(E) confinement time of CR in the Galaxy; ~ 108 yr at 1 GeV source source spectrum

  5. diffusive shock acceleration ush Fermi 1949, Krymsky 1977, Bell 1978, … shock SNR compression ratio = 4 Cas A • condition of CR • acceleration - D(р) should be anomalously small bothupstreamand downstream;CR streaming creates turbulence in shock precursor Bell 1978; Lagage & Cesarsky 1983; McKenzie & Vőlk 1982 … Bohm limit DB=vrg/3: - Hillas criterion ! Emax≈ 1014(B/Bism)Z eV Bism = 5 10-6 G in young SNRfrom synchrotron X-rays obs.Koyama et al 1995 … & theory of CR streaming instabilityBell & Lucek 2000, Bell 2004 …

  6. numerical simulation of cosmic-ray acceleration in SNR VP, Zirakashvili & Seo 2010 ApJ 718, 31 • spherically symmetric hydrodynamic eqs. • including CR pressure + diffusion-convection • eq. for cosmic ray distribution function • (compare to Berezhko et al. 1996, • Berezhko & Voelk 2000; Kang & Jones 2006) • Bohm diffusion in amplified magnetic field • B2/8π = 0.035 ρu2/2 • ( Voelk et al. 2005empirical; Bell 2004, • Zirakashvili & VP 2008theoretical) • account for Alfvenic drift w = u + Va • upstream and downstream • - relative SNR rates: SN Ia : IIP : Ib/c : IIb • = 0.32 : 0.44 : 0.22 : 0.02 • Chevalier 2004, Leaman 2008,Smart et al 2009 protons only «knee» is formed at the beginning of Sedov stage

  7. calculated interstellar spectra produced by Type Ia, IIP, Ib/c, IIb SNRs (normalized at 103 GeV) spectrum of all particles data from HEAO 3, AMS, BESS TeV, ATIC 2, TRACER experiments data from ATIC 1/2, Sokol, JACEE, Tibet, HEGRA, Tunka, KASCADE, HiRes and Auger experiments composition <lnA> based on <Xmax>; data from Hoerandel 2007

  8. another accelerator Emax = 1017 Z eV

  9. Cosmic rays of extragalactic origin: acceleration in AGN jets and propagation through background radiationin the expanding Universe Hillas (1984) diagram updated by Kotera & Olinto 2011

  10. ZGK cutoff pair and pion production on microwave & EBL photons Greisen 1966; Zatsepin & Kuzmin 1966 photodisintegration of nuclei Stecker 1969 energy scales are multiplied by 1.2, 1.0, 0.75, 0.625 for Auger, HiRes, AGASA, & Yakutsk Aloisio et al 2007

  11. Auger – heavy composition; anisotropy (69 events at >57 EeV) Abreu et al 2010, Matthiae 2010, PAO 2010 HiRes – proton composition; no significant anisotropy (13 events) Abbasi et al 2009,Sokolsky et al 2010 first results of Telescope Array on spectrum, composition, anisotropy (13 events at >57 EeV) support HiRes Thomson 2010 magnetic field effects are important everywhere: around sources, on the route to our Galaxy, in the Galaxy Dolag et al 2004, Sigl et al. 2004, Berezinsky et al 2006 Das et al. 2008, Lemoine & Waxman 2009 Pierre Auger Observatory, 69 events at E > 5.5 1019 eV (with Swift-BAT AGN density map) Abreu et al 2010 heavy composition: easy to accelerate but difficult to identify sources; production of neutrinos is suppressed

  12. extragalactic sources energy release in units1040erg/(sMpc3) needed in CR SN AGN jets GRB newly born accretion on atЕ > 1019.5eV fast magnetars galaxy clusters 3 10-4(Auger)3 10-13 3 10-4 10-310 kin.& 6 10-2forX/gamma rotationstrong shocks 8 10-3for E>109eV Lkin> 1044 erg/s low-luminosity AGN FR II + RLQ Koerding et al 2007

  13. maximum energy of accelerated particles Lovelace 1976, Biermann & Strittmatter 1987, Blandford 1993, Norman et al 1995, Waxman 1995, Farrar & Gruzinov 2009, Lemoine & Waxman 2009 - Hillas criterion general electrodynamic estimate shock acceleration - power of magnetized flow proton-electron jet jet velocity jet radius Bell 2004 - optimistic estimates of Emax for not ultrarelativistic jets

  14. Allard et al 2005, Berezinsky et al. 2006 VP et al 2010 empirical dip model account for dmin(Ljet) Galactic empirical ankle transition model heavy composition Allard 2009 Auger data 30% of Fe Galactic

  15. Conclusions Cosmic ray origin scenario where supernova remnants serve as principle accelerators of cosmic rays in the Galaxy is strongly confirmed by recent numerical simulations. SNRs can provide cosmic ray acceleration up to 5x1018 eV. More data on spectrum, composition, and anisotropy are needed in the energy range 1017 to 1019 eV, where transition from Galactic to extragalactic component occurs. Understanding discrepancy between Auger and HiRes results on composition and anisotropy is necessary for understanding of cosmic ray origin at the highest energies.

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