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

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

The problem: UHECRs are the highest energy particles observed in the universe, exceeding eV. Their origin is unknown. E max ~ 3x10 20 eV ~50J ~kinetic E of 100km/h fastball (220km/h tennis serve)

UHECR observations spectrumat least up to eV arrival directions composition light dominant up to ~<2x10 19 eV? >10 20 eV X max [g cm -2 ] globally isotropic no ID with sources AGASA HiRes before July (ICRC) 07 observations -> Kampert

UHECRs: energy losses during propagation p+  CMB → p+ e + e - E p >~5x10 17 eV p+  CMB → p+  E p >~7x10 19 eV L p, 20eV <~100 Mpc A+  CMB → A+ e + e - A+  FIRB → A-iN +iN Nagano & Watson 00 Fe p  E L loss L Fe, 20eV <~300 Mpc protons: photopair+photopion nuclei: photopair+photodisint. e.g. Stecker & Salamon 99 Watson astro-ph/ nuclei possible at the highest E! Anchordoqui+, Allard+, Armengaud+, … (Greisen-Zatsepin-Kuzmin limit)

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

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

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

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

UHECR sources: energy budget differential (per unit z) dE kin /dz=(dt/dz)∫dL L dn/dL UHECR budget u CR ~3x erg cm -3 ~10 54 erg Mpc -3 kinetic E input into the universe supernovae, 19 eV AGNs (radio galaxies) z-dep. LF Willott+ 01 L kin -L rad correlation Rawlings 92 ∝ star formation rate Porciani & Madau 01 cluster accretion L acc (M)~0.9x10 46 (M/10 15 M  ) 5/3 erg/s Press Schechter mass function Keshet+ 04 E GRB =10 53 erg, indep. of beaming E SN =10 51 erg

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

AGNs: acceleration sites from Chandra webpage Seyfert or radio-quiet quasar near-nucleus? R~ cm B~10 4 G? E max ~E p  ~<10 18 eV e.g. Szabo & Protheroe 94 UHECR accel. not expected inconsistent with observed keV-MeV

AGNs: acceleration sites inner jet (blazar) R~ cm B~0.1-1G from Chandra webpage E max ~E p  ~<10 20 eV e.g. Mannheim 93 low power (FR I) radio galaxy near-nucleus? adiabatic loss -> n conversion escape? shear-layer acceleration? accel./escape non-trivial UHECR accel. not expected

AGNs: acceleration sites inner jet (blazar) hot spot R~10 21 cm B~1mG from Chandra webpage E max ~E p  ~<10 20 eV E max ~E esc ~ eV e.g. Rachen & Biermann 93 high power (FR II) radio galaxy near-nucleus? UHECR accel. not expected accel./escape non-trivial accel./escape easiest

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

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

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

GRBs as UHECR sources Waxman & Miralda-Escude 96 time delay t(E p,D)~  2 D/4c ~10 7 yr E p,20 -2 D 100Mpc 2 l Mpc B -8 2 individual sources ->narrow spectrum at given time

GRBs: GeV-TeV  signature of UHECRs Asano & Inoue ApJ, in press arXiv: inverse Compton proton synchrotron - electrons+protons in internal shocks (prompt phase) - pair cascading, p  interactions, various radiative processes… - parameters: E sh,  t, , f B =u B /u e, assume u p =u e, p p =2

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

cluster accretion shocks accretion (minor merger) Ryu+ 03 strong shocks Kang, Rachen, Biermann 97 Fe nuclei (Z=26) E Fe, max >~10 20 eV E p, max ~ eV protons if B s ~1  G HOWEVER Mach no.

nuclei from cluster accretion shocks as UHECRs heavy nuclei E max for B s ~1  G E Fe, max ~10 20 eV Inoue, Sigl, Miniati & Armengaud, PRL submitted (astro-ph/ ) Hubble escape limit t esc ~R 2 /5  (E) E max /Z~7x10 18 eV acceleration vs CMB losses, lifetime E max R s ~3.2 Mpc V s ~2200 km/s t acc =(20/3) r g c/V s 2 shock radius, velocity, etc. Bohm limit shock accel. time

UHECRs as nuclei from clusters with EGMF no EGMF spectrum composition anisotropy eV10 20 eV f CR ~ f CR ~0.002 SI, Sigl, Miniati, Armengaud PRL, submitted (astro-ph/ ) consistent with current data (spectrum <2 sigma) with some heavy enhancement clear predictions for Auger, Telescope Array, JEM-EUSO… 100 events>4x10 19 eV 1000 events>4x10 19 eV

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

UHE proton-induced hard X+  emission from clusters Suzaku? NeXT, Simbol-X, NuSTAR HESS, MAGIC, CANG.3, VERITAS… SI, Aharonian, Sugiyama 05 Coma D=100 Mpc p(10 19 eV) +  CMB → p+ e + e - (10 16 eV) e + e - +B(~  G) → keV, e + e - +  CMB → TeV

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

concluding haiku 「松島や ああ松島や 松島や」 松尾芭蕉（？） “Matsushima, ah Matsushima, Matsushima.” - Matsuo Basho (?) 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!