1 / 22

High Energy Radiation and Cosmic Rays from Clusters of Galaxies

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). GeV. 100 keV. Auger. HESS. ZeV. TeV.

sofia
Download Presentation

High Energy Radiation and Cosmic Rays from Clusters of Galaxies

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. High Energy Radiation and Cosmic Raysfrom 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) GeV 100 keV Auger HESS ZeV TeV

  2. 1. introduction radio hard X-ray Giovannini et al. 93 current evidence for nonthermal emission: Coma Fusco-Femiano et al. 04 4.8s detection Rossetti & Molendi 04 EUV no detection Bowyer et al. 04 gamma-ray no clear evidence yet! GeV Reimer et al. 03 TeV Perkins et al. 06

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

  4. p=2(M2+1)/(M2-1) (test particle) Not all SF shocks are equal shock Mach numbers & particle spectra major merger Ryu et al. 03 weak (low M) shock -> soft spectra (p>2) minor merger, accretion also Gabici & Blasi 03 Inoue & Nagashima 05 strong (high M) shock -> hard spectra (p~2) Vazza’s poster

  5. accretion (minor merger) 2. high energy emission processes in clusters e.g. Hwang 97 Ensslin & Biermann 98 Waxman & Loeb 00 Totani & Kitayama 00 primary electron inverse Compton shock-accelerated e-+gCMB→ e-+g Emax (tIC~tacc) L schematic spectrum Ec (tIC~tshock) accretion E-2 LIC >~ Lsyn if B < 3mG(1+z)2 merger Eg eV keV MeV GeV TeV traces shock promptly (annular distribution for accretion shock) tIC<<tshock electron relativistic bremsstrahlung generally not so efficient

  6. e.g. Völk, Aharonian & Breidschwerdt 96 Berezinsky, Blasi & Ptuskin 97 pCR+pICM→p0, p+- proton-proton p0 and secondary pairs p0→2g p+-→e+e-+B(~mG)→ syn, e+e-+gCMB→ IC tloss~(nICMkppsppc)-1~100 Gyr (n/10-3 cm-3)-1 tconf ~R2/6D(E)~200 Gyr (R/Mpc)2 (D/1029cm2s-1) (E/GeV)1/3 >>tH traces gas (centrally peaked) +cosmic rays accumulated over cluster history t-integrated Mach no. distribution for individual clusters? steep (p>2) spectra? schematic spectrum L E-2 p0 merger e+- IC p0 accretion (+ radio galaxy, SN-driven wind) MeV Eg GeV TeV

  7. primary electron short trad, but no clear sources origin of radio halos: primary electron vs p-p secondary turbulent stochastic acceleration?need >GeV “seed” particlesmany uncertain parameters e.g. Brunetti et al. 01,04 p-p secondary long tpp, large-scale injection Dennison 80 but no spectral steepening requires extremely distributed injectionp0 gamma-rays close to EGRET upper limits hybrid (p-p secondary injection + turbulent acceleration) Brunetti & Blasi 05

  8. Inoue, Aharonian & Sugiyama 2005 ApJ 628, L9 UHE proton-induced pair emission from cluster accretion shocks e.g. Coma-like cluster M=2x1015 MQ(T=8.3 keV) WMAP cosmo. parameters proton Emax accel. vs CMB losses, lifetime photopair shock radius, velocity, etc. Rs~3.2 Mpc Vs~2200 km/s Bs,eq~ 6 mG lifetime escape Bohm limit shock accel. time accel. Bs=0.1 mG tacc=(20/3) h rgc/Vs2 SNR observations h~1e.g. Völk et al. 05 accel. Bs=1 mG photopion escape time tesc~R2/D(E=Emax)~R/V~2 Gyr shock lifetime tsl~R/V~2 Gyr < tadiab~6 Gyr Emax~1018-1019 eVphotopair important c.f. Kang, Rachen & Biermann 97

  9. secondary production and emission processes p+gCMB→ p+ e+e-Ep~1018eV E+-~k+-Ep~1015eV, L+-~t+-/tinj f(E>1017.7eV) Lp proton injection luminosity in accretion shocks →e+e-+B(~mG)→ syn. Eg~keV-MeV e+e-+gCMB→ IC Eg~TeV-PeV . accretion rate & luminosity M(M,z)=fgasfaccVs3/G Lacc(M,z)=fgasfaccGMM/Rs ~2.7x1046 (fgas/0.16) (facc/0.1) (M/ 2x1015 MQ)5/3 erg/s . facc=0.1 normalized from simulation Keshet et al. 03 proton luminosity & spectrum Lp(M,z)=fpLacc(M,z) fp=0.1 Fp(E,M,z) ∝ E-2 exp(-E/Emax) Aharonian 02 code solve proton & pair kinetic eq.

  10. Coma-like cluster at D=100 Mpc > TeV absorption by IRB, CMB emitted flux • large radiative efficiency from protons- hard (G~-1.5) spectrum + rollover- sensitive to B <-> primary IC, pp p0 (G~-2)

  11. Coma-like cluster at D=100 Mpc diameter ~3 deg sensitivities for 1 deg2 extended source emitted flux & detectability TeV g: HESS (d~0.1° FOV~5°), MAGIC, CANG. III, VERITAS hard X: e.g. NeXT, maybe Suzaku/HXD & XIS

  12. UHE p-induced emission in cluster accretion shocks probe of : implications • UHE proton acceleration maximum E • accretion shock • direct obs. evidence still tentative • magnetic fields at cluster outskirts • emission sensitive to B <-> pp p0 • info onB in LSS filaments, cluster B origin • IR background • intrinsic spectra to ~PeV, steady <-> TeV blazars

  13. Aharonian, Coppi & Völk 94 Coppi & Aharonian 97 Inoue, Coppi & Aharonian, in prep. cascade emission: pair halo, background pre-“absorbed” flux cascade down to GeV-TeV also for p-p p0 from core cluster pair halos- isotropic(much stronger than beamed sources)- hard spectrum probe of IRB, TeV-PeV power

  14. 3. UHECRs from cluster accretion shocks? Norman, Achterberg & Melrose ‘95 Kang, Ryu & Jones 96 Kang, Rachen & Biermann 97 energetic requirements GRB UHECR@1020 eV uCR ~10-20 erg cm-3 tCR ~0.3(1) Gyr for p (Fe) PCR ~3x1037 erg s-1Mpc-3 AGN jet massive clusters (~1015 MQ) Lcluster~1046 erg/s ncluster~10-6 Mpc-3 Pcluster~~1040 erg s-1Mpc-3 clusters energetically plausible but proton Emax insufficient oblique shocks do not help Ostrowski & Siemieniec-Ozieblo 00

  15. Inoue, Sigl, Armengaud & Miniati in prep. nuclei from cluster accretion shocks as UHECRs photopair 56Fe heavy nuclei Emax for Bs~1 mG, EFe, max>~1020 eV Bs=0.1 mG lifetime escape log tacc, tloss [yr] Bs~1 mG Johnston-Hollitt & Ekers 05 Feretti & Neumann 06 Bs=1 mG photodisint UHE nuclei propagation calculations log E [eV] • - structured IGB models based on cosmological simulations • source density ns~10-6 Mpc-3∝ baryon density • source power LCR(M)~ 3x1045 erg/s (fCR/0.1)(M/2x1015 MQ)5/3 • spectral index p=2, Emax(Z) from tacc vs. tloss, tlife • Galactic CR-like source composition (nFe/np~10-3 at fixed E/A) • CMB+FIRB losses, IGB deflections inc. all secondary nuclei

  16. UHECRs: energy losses during propagation protons: photopair+photopion p+gCMB→ p+ e+e- Ep>~5x1017eVp+gCMB→ p+ p Ep>~7x1019eV Fe Lloss p Lp, 20eV <~100 Mpc nuclei: photopair+photodisint. g A+gCMB→ A+ e+e-A+gFIRB→ A-iN +iN Nagano & Watson 00 e.g. Stecker & Salamon 99 LFe, 20eV <~300 Mpc E current data on composition HiRes stereo Xmax E>2x1019 eV no data at all (too low statistics) E<2x1019 eV light dominant but greater uncertainties than commonly believed? Watson astro-ph/0408110

  17. should be correlated with large scale struc. e.g. shock generation models based on cosmological simulations intergalactic B fields 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 -> important quantitative differences Dolag et al 04, 05 Brüggen et al 05 quantitatively very uncertain theoretically and observationally Galactic B: also important e.g. Yoshiguchi et al, Takami et al

  18. spectra composition UHE nuclei from clusters: results with IGB fCR~0.03 no IGB fCR~0.005 1019 eV 1019 eV 1020 eV 1020 eV anisotropy • spectra, anisotropy, composition • consistent with current HiRes • but not AGASA? higher Bs? • predictions: • - “GZK” cutoff >1020 eV • - heavy dominant >1019 eV • - large scale aniso. toward • few nearby sources Auger, TA, EUSO

  19. “Galactic CR-like” (solar metallicity) metallicity at cluster outskirts tentatively observed ~0.1 solar source composition e.g. Finoguenov et al 03 nonlinear acceleration effects? rigidity selection (heavy enhancement) stronger effects for accretion shocks? hard spectra at high E p<~1.5 Kang & Jones 05 Drury, Meyer & Ellison 99

  20. Inoue, Sigl & Armengaud, in prep. UHE nuclei induced pairs and emission photopair 16O 56Fe Bs=0.1 mG lifetime escape Bs=1 mG photodisint nuclei photopair+photodisint. loss importantadditional hard X-ray and g-ray emission, broader spectra Ee+e-,A ~ (me /Amp ) Z Ep Ee-,ndec ~ (mn-p /Amp ) Z Ep direct proof of nuclei acceleration constrain source composition potentially

  21. UHE p-g pair IC (+UHE Z) outskirts L hard-X/gamma-ray emission from individual clusters: roundup pri. IC Eg MeV GeV TeV p0 merger e+- IC core halo p0 accretion (+ radio galaxy SN-driven wind) MeV, GeV and TeV should look different detailed study of cluster emission through simulations warranted

  22. high energy emission from clusters summary • primary inverse Compton outskirts, MeV-GeV • p-p p0 core, GeV-TeV • p-p e+- core, MeV • UHE p (+UHE nuclei) photopair emission outskirts, MeV+TeV • cascade emission (pair halo, background) larger scales, GeV-TeV different components dominate at MeV, GeV, TeV 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!

More Related