銀河団における超高エネルギー物理過程 井上 進 (国立天文台) UHE proton induced hard X-rays & g-rays w. Felix Aharonian (MPIK), 杉山直 (国立天文台) UHE cosmic ray nuclei w. Günter Sigl, Eric Armengaud (IAP) Francesco Miniati (ETH) GLAST Suzaku 100 keV GeV Auger HESS TeV ZeV cluster accretion shocks crucial for nonthermal high energy phenomena accretion (minor merger) strong (high M) shock -> high injection, hard spectra (major) merger weak (low M) shock -> low injection, soft spectra Ryu et al. 03 UHECRs from cluster accretion shocks? Norman, Achterberg & Melrose ‘95 Kang, Ryu & Jones 96 Kang, Rachen & Biermann 97 GRB AGN jet clusters energetic requirements UHECR@1020 eV uCR ~10-20 erg cm-3 tCR ~0.3(1) Gyr for p (Fe) PCR ~3x1037 erg s-1Mpc-3 massive clusters (~1015 MQ) Lcluster~1046 erg/s ncluster~10-6 Mpc-3 Pcluster~~1040 erg s-1Mpc-3 energetically plausible, but proton Emax insufficient UHE proton-induced pair emission from cluster accretion shocks Inoue, Aharonian & Sugiyama 2005 ApJ 628, L9 max p energy accel. vs CMB losses, lifetime e.g. Coma-like cluster M=2x1015 MQ(T=8.3 keV) WMAP cosmo. parameters photopair accel. Bs=0.1 mG accel. Bs=1 mG lifetime escape photopion shock radius, velocity, etc. Rs~3.2 Mpc Vs~2200 km/s Bs,eq~ 6 mG Bohm limit shock accel. tacc=(20/3) h rgc/Vs2 SNR observations h~1 e.g. Völk et al. 05 shock lifetime ts~2 Gyr < tadiab~6 Gyr Emax~1018-1019 eV photopair important emitted flux & detectability Coma-like cluster at D=100 Mpc sensitivities for 1 deg2 extended source - large radiative efficiency from protons - hard (G~-1.5) spectrum + rollover - sensitive to B > TeV absorption by IRB, CMB <-> primary IC, pp p0 (G~-2) TeV g-ray and hard X-ray observations of clusters coming very soon!!! • Inoue, Gabici, Aharonian & Rowell, HESS proposal, accepted • Inoue, Nakazawa, Fukazawa et al., Suzaku proposal, submitted Suzaku X X QuickTimeý Dz ǻǵ êLí£ÉvÉçÉOÉâÉÄ Ç™Ç±ÇÃÉsÉNÉ`ÉÉǾå©ÇÈÇ…ÇÕïKóvÇÇ• ÅB g also expecting contributions from CANGAROO III HESS g nuclei from cluster accretion shocks as UHECRs Inoue, Sigl, Armengaud & Miniati, in prep. maximum E for heavy nuclei photopair+photopion CMB photodisint FIRB+CMB if Bs~1 mG EFe, max>~1020 eV photopair important photopair 56Fe Bs=0.1 mG Bs~1 mG Johnston-Hollitt & Ekers ‘05 lifetime escape Bs=1 mG photodisint UHE nuclei propagation calculations - realistic IGB models based on cosmological simulations - source density ~10-6 Mpc-3 ∝ baryon density - Emax(Z) from tacc vs. tloss, tlife - Galactic CR-like source composition (nFe/np~0.05) - interactions in CMB+FIRB, deflections in IGB including all secondary nuclei UHE nuclei from clusters: results spectra composition with IGB no IGB anisotropy spectra, anisotropy, composition • consistent with current HiRes but not AGASA… • predictions: - “GZK” cutoff >1020 eV - heavy dominant >1019 eV - one or few extended source(s) >4x1019eV UHE nuclei induced pairs 16O photopair 56Fe Bs=0.1 mG lifetime escape Bs=1 mG photodisint photopair important additional hard X-ray and g-ray emission, broader spectra direct proof of nuclei acceleration in cluster accretion shocks summary UHE processes in cluster accretion shocks UHE p-induced emission • acceleration to E~1018-1019eV • 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, … stay tuned for upcoming HESS & Suzaku observations! UHECR nuclei • Fe acceleration to E~1020eV plausible if B~1 mG • UHECR flux and spectra consistent if nFe/np~0.05 at source • predictions for Auger, TA, EUSO: - spectra: cutoff >~1020 eV - composition: p dominant ~<1019 eV, Fe dominant >~1020 eV - anisotropy: a few extended sources >~4x1019 eV • additional hard X/TeV from pairs HESS, Suzaku, … proton injection luminosity in accretion shocks accretion .M(M,z)=fratef &Vluminosity 3 gas acc s /G . Lacc(M,z)=fgasfaccGMM/Rs ~2.7x1046 (fgas/0.16) (facc/0.1) (M/ 2x1015 MQ)5/3 erg/s proton luminosity & spectrum Lp(M,z)=fpLacc(M,z) fp=0.1 Fp(E,M,z) ∝ E-2 exp(-E/Emax) secondary production and emission processes p+gCMB→ p+ e+eEp~1018eV E+-~k+-Ep~1015eV, L+-~t+-/tinj f(E>1017.7eV) Lp → e+e-+B(~mG)→ syn. Eg~keV-MeV e+e-+gCMB→ IC Eg~TeV-PeV Aharonian 02 code solve proton & pair kinetic eq. model vs Coma data sensitivities for 1 deg2 extended source - hard X? need large p luminosity - radio something else hard X data <1 deg UHECRs: energy losses during propagation p+gCMB→ p+ e+e- Ep>~5x1017eV p+gCMB→ p+ p Ep>~7x1019eV QuickTimeý Dz ǻǵ êLí£ÉvÉçÉOÉâÉÄ Ç™Ç±ÇÃÉsÉNÉ`ÉÉǾå©ÇÈÇ…ÇÕïKóvÇÇ• ÅB Dp, 20eV <~100 Mpc A+gFIRB→ A+ e+eA+gFIRB→ A-iN +iN intergalactic B fields 1. shock generation models based on Sigl, Miniati cosmological simulations & Ensslin 03,04 2. uniform seed normalized to cluster magnetic fields source distribution Ns=10-6 Mpc-3, ∝ baryon density randomly distribute, many realizations source composition “Galactic CR-like” observed Galactic CR at low E heavy elements enhanced, Fe/p~0.1 Sigl & Armengaud 05 observed metallicity at cluster outskirts ~0.1 solar Finoguenov et al 03 observed Galactic CR at high E further enhanced? Fe/p~1/4 @1015eV Hoerandel 05 current data on UHE composition Watson astro-ph/0408110 - E>2x1019 eV: no data at all! (too low statistics) - E<2x1019 eV: much greater uncertainties than often advertised results: sky map for 1 particular realization With field: Isotropy consistent with current statistics Without field: probably too anisotropic due to low source density No anisotropy for ~100 events above 4x1019 eV. Significant anisotropy should appear for > 1000 events above 4x1019 eV.
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