High Energy Radiation and Cosmic Rays from Clusters

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High Energy Radiation and Cosmic Rays from Clusters of Galaxies collaborators: F. Aharonian (MPIK),

High Energy Radiation and Cosmic Rays from Clusters of Galaxies collaborators: F. Aharonian (MPIK), N. Sugiyama (NAO), P. Coppi (Yale) G. Sigl, E. Armengaud (IAP), F. Miniati (ETH) GLAST Suzaku Susumu Inoue (Nat. Astron. Obs. Japan) 100 ke. V Ge. V Auger HESS Ze. V Te. V

1. introduction current evidence for nonthermal emission: Coma radio Giovannini et al. 93 hard

1. introduction current evidence for nonthermal emission: Coma radio Giovannini et al. 93 hard X-ray 4. 8 s detection Fusco-Femiano et al. 04 Rossetti & Molendi 04 EUV Bowyer et al. 04 no detection gamma-ray no clear evidence yet! Ge. V Reimer et al. 03 Te. V Perkins et al. 06

large scale structure formation (SF) shocks formation of galaxies, groups, clusters. . . =

large scale structure formation (SF) shocks formation of galaxies, groups, clusters. . . = hierarchical, dark matter-driven mergers and accretion → shock formation → gas heating + nonthermal particle acceleration → nonthermal radiation clusters are forming this very moment! thermal emission shock velocities cosmological hydro simulations by Ryu et al. 03

shock Mach numbers & particle spectra Not all SF shocks are equal major merger

shock Mach numbers & particle spectra Not all SF shocks are equal major merger p=2(M 2+1)/(M 2 -1) (test particle) Ryu et al. 03 weak (low M) shock -> soft spectra (p>2) minor merger, accretion strong (high M) shock -> hard spectra (p~2) also Gabici & Blasi 03 Inoue & Nagashima 05 Vazza’s poster

2. high energy emission processes in clusters primary electron inverse Compton shock-accelerated e-+g. CMB→

2. high energy emission processes in clusters primary electron inverse Compton shock-accelerated e-+g. CMB→ e-+g L schematic spectrum e. g. Hwang 97 Ensslin & Biermann 98 Waxman & Loeb 00 Totani & Kitayama 00 Emax Ec (t. IC~tacc) (t. IC~tshock) accretion E-2 LIC >~ Lsyn if B < 3 m. G(1+z)2 merger e. V ke. V Me. V Ge. V Te. V Eg t. IC<<tshock traces shock promptly (annular distribution for accretion shock) electron relativistic bremsstrahlung generally not so efficient accretion (minor merger)

proton-proton p 0 and secondary pairs p. CR+p. ICM→ p 0, e. g. Völk,

proton-proton p 0 and secondary pairs p. CR+p. ICM→ p 0, e. g. Völk, Aharonian & Breidschwerdt 96 Berezinsky, Blasi & Ptuskin 97 p+- p 0→ 2 g p+-→e+e-+B(~m. G)→ syn, e+e-+g. CMB→ IC tloss~(n. ICMkppsppc)-1~100 Gyr (n/10 -3 cm-3)-1 >>t. H 2 2 29 2 -1 1/3 tconf ~R /6 D(E)~200 Gyr (R/Mpc) (D/10 cm s ) (E/Ge. V) traces gas (centrally peaked) +cosmic rays accumulated over cluster history t-integrated Mach no. distribution for individual clusters? steep (p>2) spectra? L schematic spectrum e+- IC Me. V E-2 p 0 merger Ge. V p 0 accretion (+ radio galaxy, SN-driven wind) Te. V Eg

origin of radio halos: primary electron vs p-p secondary primary electron short trad, but

origin of radio halos: primary electron vs p-p secondary primary electron short trad, but no clear sources turbulent stochastic acceleration? e. g. Brunetti et al. 01, 04 need >Ge. V “seed” particles many uncertain parameters p-p secondary long tpp, large-scale injection Dennison 80 but no spectral steepening requires extremely distributed injection p 0 gamma-rays close to EGRET upper limits hybrid (p-p secondary injection + turbulent acceleration) Brunetti & Blasi 05

UHE proton-induced pair emission from cluster accretion shocks Inoue, Aharonian & Sugiyama 2005 Ap.

UHE proton-induced pair emission from cluster accretion shocks Inoue, Aharonian & Sugiyama 2005 Ap. J 628, L 9 cluster proton Emax accel. vs CMB losses, lifetime e. g. Coma-like 15 M=2 x 10 MQ(T=8. 3 ke. V) WMAP cosmo. parameters photopair lifetime escape accel. Bs=0. 1 m. G accel. Bs=1 m. G photopion c. f. Kang, Rachen & Biermann 97 shock radius, velocity, etc. Rs~3. 2 Mpc Vs~2200 km/s Bs, eq~ 6 m. G Bohm limit shock accel. time tacc=(20/3) h rgc/Vs 2 SNR observations h~1 e. g. Völk et al. 05 escape time tesc~R 2/D(E=Emax)~R/V~2 Gyr shock lifetime tsl~R/V~2 Gyr < tadiab~6 Gyr Emax~1018 -1019 e. V photopair important

secondary production and emission processes p+g. CMB→ p+ e+e. Ep~1018 e. V E+-~k+-Ep~1015 e.

secondary production and emission processes p+g. CMB→ p+ e+e. Ep~1018 e. V E+-~k+-Ep~1015 e. V, L+-~t+-/tinj f(E>1017. 7 e. V) Lp → e+e-+B(~m. G)→ syn. Eg~ke. V-Me. V e+e-+g. CMB→ IC Eg~Te. V-Pe. V proton injection luminosity in accretion shocks accretion. M(M, z)=fratef &Vluminosity 3 gas acc s /G. Lacc(M, z)=fgasfacc. GMM/Rs ~2. 7 x 1046 (fgas/0. 16) (facc/0. 1) (M/ 2 x 1015 MQ)5/3 erg/s proton luminosity & spectrum Lp(M, z)=fp. Lacc(M, z) fp=0. 1 Fp(E, M, z) ∝ E-2 exp(-E/Emax) facc=0. 1 normalized from simulation Keshet et al. 03 Aharonian 02 code solve proton & pair kinetic eq.

emitted flux Coma-like cluster at D=100 Mpc > Te. V absorption by IRB, CMB

emitted flux Coma-like cluster at D=100 Mpc > Te. V absorption by IRB, CMB - large radiative efficiency from protons - hard (G~-1. 5) spectrum + rollover - sensitive to B <-> primary IC, pp p 0 (G~-2)

emitted flux & detectability sensitivities for 1 deg 2 extended source Coma-like cluster at

emitted flux & detectability sensitivities for 1 deg 2 extended source Coma-like cluster at D=100 Mpc diameter ~3 deg Te. V g : HESS (d ~0. 1° FOV~5°), MAGIC, CANG. III, VERITAS hard X: e. g. Ne. XT, maybe Suzaku/HXD & XIS

implications UHE p-induced emission in cluster accretion shocks probe of : • UHE proton

implications UHE p-induced emission in cluster accretion shocks probe of : • UHE proton acceleration maximum E • accretion shock direct obs. evidence still tentative • magnetic fields at cluster outskirts emission sensitive to B <-> pp p 0 info on B in LSS filaments, cluster B origin • IR background intrinsic spectra to ~Pe. V, steady <-> Te. V blazars

cascade emission: pair halo, background Aharonian, Coppi & Völk 94 Coppi & Aharonian 97

cascade emission: pair halo, background Aharonian, Coppi & Völk 94 Coppi & Aharonian 97 Inoue, Coppi & Aharonian, in prep. pre-“absorbed” flux cascade down to Ge. V-Te. V also for p-p p 0 from core cluster pair halos - isotropic (much stronger than beamed sources) - hard spectrum probe of IRB, Te. V-Pe. V power

3. UHECRs from cluster accretion shocks? Norman, Achterberg & Melrose ‘ 95 Kang, Ryu

3. 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 e. V u. CR ~10 -20 erg cm-3 t. CR ~0. 3(1) Gyr for p (Fe) PCR ~3 x 1037 erg s-1 Mpc-3 massive clusters (~1015 MQ) Lcluster~1046 erg/s ncluster~10 -6 Mpc-3 Pcluster~~1040 erg s-1 Mpc-3 energetically plausible but proton Emax insufficient oblique shocks do not help Ostrowski & Siemieniec-Ozieblo 00

Bs~1 m. G Johnston-Hollitt & Ekers 05 Feretti & Neumann 06 photopair log tacc,

Bs~1 m. G Johnston-Hollitt & Ekers 05 Feretti & Neumann 06 photopair log tacc, tloss [yr] nuclei from cluster accretion shocks as UHECRs Inoue, Sigl, Armengaud & Miniati 56 Fe in prep. heavy nuclei Emax for Bs~1 m. G, EFe, max>~1020 e. V Bs=0. 1 m. G lifetime escape Bs=1 m. G photodisint UHE nuclei propagation calculations log E [e. V] - structured IGB models based on cosmological simulations - source density ns~10 -6 Mpc-3 ∝ baryon density - source power LCR(M)~ 3 x 1045 erg/s (f. CR/0. 1)(M/2 x 1015 MQ)5/3 - spectral index p=2, Emax(Z) from tacc vs. tloss, tlife - Galactic CR-like source composition (n. Fe/np~10 -3 at fixed E/A) - CMB+FIRB losses, IGB deflections inc. all secondary nuclei

UHECRs: energy losses during propagation protons: photopair+photopion Fe Lloss p p+g. CMB→ p+ e+e-

UHECRs: energy losses during propagation protons: photopair+photopion Fe Lloss p p+g. CMB→ p+ e+e- Ep>~5 x 1017 e. V p+g. CMB→ p+ p Ep>~7 x 1019 e. V Lp, 20 e. V <~100 Mpc nuclei: photopair+photodisint. g A+g. CMB→ A+ e+e. A+g. FIRB→ A-i. N +i. N Nagano & Watson 00 LFe, 20 e. V <~300 Mpc e. g. Stecker & Salamon 99 E current data on composition Hi. Res stereo Xmax E>2 x 1019 e. V no data at all (too low statistics) Watson astro-ph/0408110 E<2 x 1019 e. V light dominant but greater uncertainties than commonly believed?

intergalactic B fields should be correlated with large scale struc. e. g. shock generation

intergalactic B fields should be correlated with large scale struc. e. g. shock generation models based on cosmological simulations normalized to cluster B fields Ryu, Kang & Biermann 98 Sigl, Miniati & Ensslin 03, 04 small box size -> periodic boundary unconstrained -> average over realizations no Galactic B different assumptions, numerical methods Dolag et al 04, 05 Brüggen et al 05 -> important quantitative differences quantitatively very uncertain theoretically and observationally Galactic B: also important e. g. Yoshiguchi et al, Takami et al

UHE nuclei from clusters: results spectra composition with IGB f. CR~0. 03 no IGB

UHE nuclei from clusters: results spectra composition with IGB f. CR~0. 03 no IGB f. CR~0. 005 1019 e. V anisotropy 1020 e. V 1019 e. V 1020 e. V spectra, anisotropy, composition • consistent with current Hi. Res but not AGASA? higher Bs? • predictions: Auger, TA, EUSO - “GZK” cutoff >1020 e. V - heavy dominant >1019 e. V - large scale aniso. toward few nearby sources

source composition “Galactic CR-like” (solar metallicity) metallicity at cluster outskirts tentatively observed ~0. 1

source composition “Galactic CR-like” (solar metallicity) metallicity at cluster outskirts tentatively observed ~0. 1 solar e. g. Finoguenov et al 03 nonlinear acceleration effects? hard spectra at high E p<~1. 5 rigidity selection (heavy enhancement) stronger effects for accretion shocks? Kang & Jones 05 Drury, Meyer & Ellison 99

UHE nuclei induced pairs and emission Inoue, Sigl & Armengaud, in prep. 16 O

UHE nuclei induced pairs and emission Inoue, Sigl & Armengaud, in prep. 16 O photopair 56 Fe Bs=0. 1 m. G lifetime escape Bs=1 m. G photodisint nuclei photopair+photodisint. loss important additional hard X-ray and g-ray emission, broader spectra Ee+e-, A ~ (me /Amp ) Z Ep Ee-, ndec ~ (mn-p /Amp ) Z Ep potentially direct proof of nuclei acceleration constrain source composition

hard-X/gamma-ray emission from individual clusters: roundup outskirts UHE p-g pair IC (+UHE Z) L

hard-X/gamma-ray emission from individual clusters: roundup outskirts UHE p-g pair IC (+UHE Z) L pri. IC Me. V halo core e+- IC Ge. V Te. V Eg p 0 merger p 0 accretion (+ radio galaxy SN-driven wind) Me. V, Ge. V and Te. V should look different detailed study of cluster emission through simulations warranted

summary high energy emission from clusters • primary inverse Compton outskirts, Me. V-Ge. V

summary high energy emission from clusters • primary inverse Compton outskirts, Me. V-Ge. V • p-p p 0 core, Ge. V-Te. V • p-p e+- core, Me. V • UHE p (+UHE nuclei) photopair emission outskirts, Me. V+Te. V • cascade emission (pair halo, background) larger scales, Ge. V-Te. V different components dominate at Me. V, Ge. V, Te. V merger and accretion shock contribute different spectra probe of structure formation, non-gravitational effects Inoue & Nagashima; Inoue, Nagashima & Völk, in prep. potentially very rich information fertile new field of high energy astrophysics!