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Origin of Ultra High Energy Cosmic Rays

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Origin of Ultra High Energy Cosmic Rays

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  1. Astrophysical Sources, Gamma-Ray Connection Origin of Ultra High Energy Cosmic Rays Susumu Inoue (NAOJ) astro-ph/0701835 (brief review) GRBs AGNs clusters collaborators: G. Sigl (APC), F. Miniati (ETH), E. Armengaud (CEA) F. Aharonian (MPIK), N. Sugiyama (Nagoya) K. Asano (NAOJ)

  2. 1. general aspects outline propagation: extragalactic radiation and B fields source candidates: acceleration & energetics 2. physics of selected UHECR source candidates I. AGNs different AGN types II. GRBs GeV-TeV g-rays III. cluster accretion shocks UHECR nuclei UHE p-induced X/g-rays UHECR-induced secondary X/g radiation signatures neutrinos -> Halzen

  3. UHECRs are the highest energy particles observed in the universe, exceeding 1020 eV. Their origin is unknown. The problem: Emax~ 3x1020 eV ~50J ~kinetic E of 100km/h fastball (220km/h tennis serve)

  4. before July (ICRC) 07 spectrum at least up to 1020 eV observations -> Kampert UHECR observations AGASA HiRes light dominant up to ~<2x1019 eV? composition arrival directions globally isotropic no ID with sources Xmax [g cm-2] >1020 eV

  5. UHECRs: energy losses during propagation protons: photopair+photopion p+gCMB→ p+ e+e- Ep>~5x1017eVp+gCMB→ p+ p Ep>~7x1019eV Fe Lloss p (Greisen-Zatsepin-Kuzmin limit) Lp, 20eV <~100 Mpc g nuclei: photopair+photodisint. A+gCMB→ A+ e+e-A+gFIRB→ A-iN +iN Nagano & Watson 00 e.g. Stecker & Salamon 99 E LFe, 20eV <~300 Mpc nuclei possible at the highest E! Watson astro-ph/0408110 Anchordoqui+, Allard+, Armengaud+, …

  6. should be correlated with large scale struc. very uncertain observationally and theoretically extragalactic B fields crucial differences between theoretical models Sigl, Miniati & Ensslin 03,04 Dolag+ 04, 05 Brüggen+ 05 propagation -> Das Kang+ 07 also uncertain Galactic B fields secondary photon/neutrino signatures desirable to pinpoint sources!

  7. topological defects, EHE n Z-bursts, UHECRons, superheavy DM… top-down models: very strongly constrained Auger spectrum Auger photon limits Yamamoto+ arXiv: 0707.2638 Semikoz+ arXiv: 0706.2690 superheavy DM ruled out spectral steepening at E>1019.6 eV (6 sigma) also claimed by HiRes

  8. adapted from Yoshida & Dai 98 “Hillas plot” UHECR sources: acceleration E ≦ Ze B R (v/c) confinement B GRBs B~∝R-1 Emax acceleration vs: escape source lifetime adiab. expansion loss radiative loss AGN jets clusters R

  9. shock acceleration • - power-law spectrum • dN/dE~∝E-2 for strong shock • very efficient • up to ~50% of kinetic energy upstream downstream shock front • consistent with observations • in-situ: earth-solar wind, … • SNRs, radio galaxy hot spots, … acceleration -> Berezhko

  10. kinetic E input into the universe UHECR sources: energy budget AGNs (radio galaxies) z-dep. LF Willott+ 01 Lkin-Lrad correlation Rawlings 92 supernovae, GRBs ∝ star formation rate Porciani & Madau 01 ESN=1051 erg EGRB=1053 erg, indep. of beaming cluster accretion Press Schechter mass function Lacc(M)~0.9x1046 (M/1015 MQ)5/3 erg/s Keshet+ 04 UHECR budget @1019 eV differential (per unit z) uCR ~3x10-19 erg cm-3 ~1054 erg Mpc-3 dEkin/dz=(dt/dz)∫dL L dn/dL

  11. GeV blazar FR II radio galaxy supermassive black hole +accretion disk (flow) active galactic nuclei (AGNs) high- power radio-loud (relativistic jet) ~<1% low- power ~9% radio- quiet (no jet) ~90% TeV blazar (BL Lac) FR I radio galaxy Seyfert galaxy radio-quiet quasar activity timescales ~107-108 yr ~<UHECR delay time

  12. near-nucleus? R~1013-1014 cm B~104G? Seyfert or radio-quiet quasar AGNs: acceleration sites Emax~Epg~<1018eV e.g. Szabo & Protheroe 94 inconsistent with observed keV-MeV UHECR accel. not expected from Chandra webpage

  13. near-nucleus? low power (FR I) radio galaxy AGNs: acceleration sites UHECR accel. not expected inner jet (blazar) R~1016-1017 cm B~0.1-1G Emax~Epg~<1020eV e.g. Mannheim 93 adiabatic loss -> n conversion escape? shear-layer acceleration? accel./escape non-trivial from Chandra webpage

  14. near-nucleus? high power (FR II) radio galaxy AGNs: acceleration sites UHECR accel. not expected inner jet (blazar) Emax~Epg~<1020eV accel./escape non-trivial hot spot R~1021 cm B~1mG Emax~Eesc~1020-21eV e.g. Rachen & Biermann 93 from Chandra webpage accel./escape easiest

  15. AGNs: anisotropy expectations? Takami+ 06 ns=5x10-6 Mpc-3 anisotropy expectations for different AGN types Takami, SI+, in prep.

  16. proton synchrotron from hot spots/knots AGNs: UHECR-induced secondary emission Aharonian 02 “GZK” radiation from intracluster AGNs Armengaud, Sigl & Miniati 05

  17. internal + external (forward + reverse) shocks GRBs UHECR accel. site Waxman 95, Vietri 95 Gialis & Pelletier 03 Wick, Dermer & Atoyan 04 adapted from Meszaros 01 radio-IR-opt-X afterglow prompt X-g emission optical flash, radio flare internal shocks external reverse shock external forward shock

  18. Waxman & Miralda-Escude 96 GRBs as UHECR sources time delayt(Ep,D)~q2D/4c ~107 yr Ep,20-2 D100Mpc2lMpcB-82 individual sources->narrow spectrum at given time

  19. Asano & Inoue ApJ, in press arXiv:0705.2910 • electrons+protons in internal shocks (prompt phase) • pair cascading, pg interactions, various radiative processes… • parameters: Esh, Dt, G, fB=uB/ue, assume up=ue, pp=2 GRBs: GeV-TeV g signature of UHECRs proton synchrotron inverse Compton

  20. GRBs: GeV-TeV g signature of UHECRs secondary pair synchrotron+ muon synchrotron+ double (multiple) breaks -> proton signature GLAST, MAGIC (II), HESS (II), VERITAS, CANG.III … MILAGRO, Auger…

  21. accretion (minor merger) cluster accretion shocks Ryu+ 03 strong shocks Mach no. protons Ep, max~ 1018-1019 eV Kang, Rachen, Biermann 97 HOWEVER Fe nuclei (Z=26) if Bs~1 mG EFe, max>~1020 eV

  22. Inoue, Sigl, Miniati & Armengaud, PRL submitted (astro-ph/0701167) nuclei from cluster accretion shocks as UHECRs Emax acceleration vs CMB losses, lifetime shock radius, velocity, etc. Hubble Rs~3.2 Mpc Vs~2200 km/s Bohm limit shock accel. time tacc=(20/3) rgc/Vs2 escape limit tesc~R2/5k(E) Emax/Z~7x1018 eV heavy nuclei Emax for Bs~1 mGEFe, max~1020 eV

  23. SI, Sigl, Miniati, Armengaud PRL, submitted (astro-ph/0701167) UHECRs as nuclei from clusters spectrum anisotropy with EGMF fCR~0.005-0.3 100 events>4x1019eV no EGMF fCR~0.002 composition 1000 events>4x1019eV consistent with current data (spectrum <2 sigma) with some heavy enhancement clear predictions for Auger, Telescope Array, JEM-EUSO… 1019 eV 1020 eV

  24. composition latest Auger results Unger+ arXiv: 0706.1495 mixed composition at all E becoming heavier at highest E?

  25. p(1019eV) +gCMB→ p+ e+e- (1016eV) SI, Aharonian, Sugiyama 05 UHE proton-induced hard X+g emission from clusters e+e-+B(~mG)→keV, e+e-+gCMB→TeV Coma D=100 Mpc Suzaku? NeXT, Simbol-X, NuSTAR HESS, MAGIC, CANG.3, VERITAS…

  26. AGNs summary different likelihood for different types high-power RG > low-power RG > radio-quiet GRBs tight energy budget characteristic GeV-TeV signatures cluster accretion shocks (nuclei) consistent for some enhancement in heavy composition characteristic spectra, anisotropy, composition hard X-rays + TeV gamma-rays other sources? starburst galaxies … Galactic NS, magnetars … none of these?

  27. 宇宙線 ああガンマ線 ニュートリノ “Cosmic rays, ah Gamma-rays, Neutrinos.” The real beauty will be in the combination of the techniques! concluding haiku 「松島や ああ松島や 松島や」  松尾芭蕉(?) “Matsushima, ah Matsushima, Matsushima.” - Matsuo Basho (?)