銀河団における超高エネルギー物理過程 w. Felix Aharonian (MPIK), 杉山直 ( 国立天文台 ) 井上 進 ( 国立天文台 ) w. Günter Sigl, Eric Armengaud (IAP) Francesco Miniati (ETH) ZeV GeV TeV 100 keV HESS Auger GLAST Suzaku UHE proton induced hard X-rays &  -rays UHE cosmic ray nuclei

cluster accretion shocks accretion (minor merger) (major) merger Ryu et al. 03 strong (high M ) shock -> high injection, hard spectra weak (low M ) shock -> low injection, soft spectra crucial for nonthermal high energy phenomena

UHECRs from cluster accretion shocks? Norman, Achterberg & Melrose ‘95 Kang, Ryu & Jones 96 Kang, Rachen & Biermann 97 GRB AGN jet clusters energetic requirements L cluster ~10 46 erg/s n cluster ~10 -6 Mpc -3 P cluster ~~10 40 erg s -1 Mpc eV u CR ~ erg cm -3  CR ~0.3(1) Gyr for p (Fe) P CR ~3x10 37 erg s -1 Mpc -3 massive clusters (~10 15 M  ) energetically plausible, but proton E max insufficient

UHE proton-induced pair emission from cluster accretion shocks accel. vs CMB losses, lifetime photopion lifetime escape accel. B s =0.1  G photopair accel. B s =1  G R s ~3.2 Mpc V s ~2200 km/s e.g. Coma-like cluster M=2x10 15 M  (T=8.3 keV) WMAP cosmo. parameters B s,eq ~ 6  G E max ~ eV photopair important t acc =(20/3)  r g c/V s 2 shock radius, velocity, etc. Bohm limit shock accel. SNR observations  ~1 e.g. Völk et al. 05 shock lifetime t s ~2 Gyr < t adiab ~6 Gyr max p energy Inoue, Aharonian & Sugiyama 2005 ApJ 628, L9

emitted flux & detectability Coma-like cluster at D=100 Mpc sensitivities for 1 deg 2 extended source - large radiative efficiency from protons - hard (  ~-1.5) spectrum + rollover - sensitive to B primary IC, pp  0 (  ~-2) > TeV absorption by IRB, CMB

Inoue, Gabici, Aharonian & Rowell, HESS proposal, accepted HESS   coming very soon!!! Suzaku X X TeV  -ray and hard X-ray observations of clusters Inoue, Nakazawa, Fukazawa et al., Suzaku proposal, submitted also expecting contributions from CANGAROO III

nuclei from cluster accretion shocks as UHECRs photopair+photopion CMB photodisint FIRB+CMB photodisint photopair B s =0.1  G B s =1  G B s ~1  G Johnston-Hollitt & Ekers ‘05 maximum E for heavy nuclei if B s ~1  G E Fe, max >~10 20 eV photopair important Inoue, Sigl, Armengaud & Miniati, in prep. UHE nuclei propagation calculations - realistic IGB models based on cosmological simulations - source density ~10 -6 Mpc -3 ∝ baryon density - E max (Z) from t acc vs. t loss, t life - Galactic CR-like source composition (n Fe /n p ~0.05) - interactions in CMB+FIRB, deflections in IGB including all secondary nuclei 56 Fe lifetime escape

UHE nuclei from clusters: results with IGB no IGB spectracomposition anisotropy spectra, anisotropy, composition consistent with current HiRes but not AGASA… predictions: - “GZK” cutoff >10 20 eV - heavy dominant >10 19 eV - one or few extended source(s) >4x10 19 eV

UHE nuclei induced pairs photodisint photopair B s =0.1  G B s =1  G 56 Fe 16 O lifetime escape photopair important additional hard X-ray and  -ray emission, broader spectra direct proof of nuclei acceleration in cluster accretion shocks

summary acceleration to E~ eV efficient secondary pair emission -> hard X sync. Suzaku, NeXT (imaging), … -> TeV IC HESS, CANG.III, other current IACTs important probe of UHE p acceleration, B in cluster outskirts, … UHE p-induced emission stay tuned for upcoming HESS & Suzaku observations! UHECR nuclei Fe acceleration to E~10 20 eV plausible if B~1  G UHECR flux and spectra consistent if n Fe /n p ~0.05 at source predictions for Auger, TA, EUSO: - spectra: cutoff >~10 20 eV - composition: p dominant ~ ~10 20 eV - anisotropy: a few extended sources >~4x10 19 eV additional hard X/TeV from pairs HESS, Suzaku, … UHE processes in cluster accretion shocks

proton injection luminosity in accretion shocks accretion rate & luminosity M(M,z)=f gas f acc V s 3 /G L acc (M,z)=f gas f acc GMM/R s ~2.7x10 46 (f gas /0.16) (f acc /0.1) (M/ 2x10 15 M  ) 5/3 erg/s proton luminosity & spectrum L p (M,z)=f p L acc (M,z) f p =0.1 F p (E,M,z) ∝ E -2 exp(-E/E max ) secondary production and emission processes p+  CMB → p+ e + e - E p ~10 18 eV E +- ~  +- E p ~10 15 eV, L +- ~t +- /t inj f(E> eV) L p → e + e - +B(~  G) → syn. E  ~keV-MeV e + e - +  CMB → IC E  ~TeV-PeV Aharonian 02 code solve proton & pair kinetic eq...

model vs Coma data - hard X? need large p luminosity - radio something else sensitivities for 1 deg 2 extended source hard X data <1 deg

UHECRs: energy losses during propagation p+  CMB → p+ e + e - E p >~5x10 17 eV p+  CMB → p+  E p >~7x10 19 eV D p, 20eV <~100 Mpc A+  FIRB → A+ e + e - A+  FIRB → A-iN +iN

intergalactic B fields models based on cosmological simulations Sigl, Miniati & Ensslin 03,04 1. shock generation2. uniform seed normalized to cluster magnetic fields source distribution N s =10 -6 Mpc -3, ∝ baryon density randomly distribute, many realizations

source composition Sigl & Armengaud 05 observed Galactic CR at low E heavy elements enhanced, Fe/p~0.1 observed Galactic CR at high E further enhanced? 15 eV Hoerandel 05 “Galactic CR-like” observed metallicity at cluster outskirts ~0.1 solar Finoguenov et al 03

current data on UHE composition Watson astro-ph/ E>2x10 19 eV: no data at all! (too low statistics) - E<2x10 19 eV: much greater uncertainties than often advertised

With field: Isotropy consistent with current statistics Without field: probably too anisotropic due to low source density No anisotropy for ~100 events above 4x10 19 eV. Significant anisotropy should appear for > 1000 events above 4x10 19 eV. for 1 particular realization results: sky map