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What do we know about the identity of CR sources? Boaz Katz, Kfir Blum Eli Waxman Weizmann Institute, ISRAEL
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The cosmic-ray spectrum & Composition Cosmic-ray E [GeV] log [dJ/dE] 1 10 6 10 E -2.7 E -3 Heavy Nuclei Protons Light Nuclei? Galactic X-Galactic (?) [Blandford & Eichler, Phys. Rep. 87; Axford, ApJS 94; Nagano & Watson, Rev. Mod. Phys. 00] Source: Supernovae(?) Source? Lighter
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Intra-cluster CRs Observed in radio, HXR Will not be discussed here See D. Kushnir ’ s talk: [arXiv:0903.2271, 0903.2275, 0905.1950] * Likely origin- Accretion shocks * Predictions for Fermi, TeV (HESS, MAGIC)
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Galactic CR sources: Constraints Max >~10 15 eV Energy production rate L G,CR ~(A disk h CR )U CR /t CR * U CR ~1 eV/cm 3, * Propagation: 2 nd -ary (& primary) composition L G,CR ~cA disk U CR ( disk / sec )~10 49.5 erg/100yr [Blandford & Eichler, Phys. Rep. 87; Axford, ApJS 94]
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Galactic CR sources: SNe? Motivation for SNe as sources: * L G,CR ~10 -1.5 L G,SN * Max ~10 15 eV * e - acceleration to 10 15 eV from X emission TeV photons from SNRs (RXJ1713.7-3946,RXJ0852.0-4622) * Claim: must be due to pp pion production Confirms CR ion production [e.g. Koyama et al. 95] [e.g. Aharonian et al. 04--07]
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TeV must be due to e - IC pp origin in contradiction with radio, thermal-X (non detection of thermal X n<~0.1/cm 3 ): TeV consistent with e - IC, including “ cutoffs ” : Claims RE e - IC inconsistency: Detailed spectral shape near h c, where theoretical predictions are highly uncertain [Katz & Waxman 07]
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SNR TeV lessons Search at high n SNRs: Strong Thermal X, weak non-Thermal Difficult to prove pp based on EM obs. Highly simplified, phenomenological models (and plenty of room for complications: inhomogeneous plasma, particle spectra … ) [Katz & Waxman 07]
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PAMELA: New e+ sources? Apply anti-p, e + consistent with 2 nd ary origin Radiative e + losses- depend on propagation in Galaxy (poorly understood) * At 20GeV: f rad ~0.3~f 10 Be * Above 20GeV: If PAMELA correct slightly rising f rad ( ) [Katz, Blum & Waxman 09]
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What do we know about >10 19 eV CRs? Max : L B >10 12 ( 2 / ) ( /Z 10 20 eV) 2 L sun (see Dermer ’ s talk) Composition [Waxman 95, 04]
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Composition clues HiRes 2005
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Westerhoff (Auger) 2009
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What do we know about >10 19 eV CRs? Max : L B >10 12 ( 2 / ) ( /Z 10 20 eV) 2 L sun Composition: HiRes – protons, Auger- becoming heavier @ 3x10 19 eV? !!Uncertain interaction cross sections Energy production rate: - L B >10 12 L sun & R L = /eB=40 p,20 kpc Likely X-Galactic
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[Waxman 1995; Bahcall & Waxman 03] [Katz & Waxman 09] 2 (dN/d )= 2 (dQ/d ) t eff. (t eff. : p + CMB N + Assume: p, dQ/d ~(1+z) m - >10 19.3 eV: consistent with protons, 2 (dQ/d ) ~10 43.7 erg/Mpc 3 yr + GZK 2 (dQ/d ) ~Const.: Consistent with shock acceleration [Reviews: Blandford & Eichler 87; Waxman 06 cf. Lemoine & Revenu 06] Flux & Spectrum ct eff [Mpc] GZK (CMB) suppression log( 2 dQ/d ) [erg/Mpc 2 yr]
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G-XG Transition at 10 18 eV? Fine tuning Inconsistent spectrum [Katz & Waxman 09]
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What do we know about >10 19 eV CRs? Max : L B >10 12 ( 2 / ) ( /Z 10 20 eV) 2 L sun Composition HiRes – protons, Auger- becoming heavier Uncertain interaction cross sections Energy production rate - L B >10 12 L sun & R L = /eB=40 p,20 kpc Likely X-Galactic - Consistent with protons, 2 (dQ/d ) ~10 43.7 erg/Mpc 3 yr + GZK
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UHE CR sources Constraints: - L>10 12 ( 2 / ) L sun - 2 (dQ/d ) ~10 43.7 erg/Mpc 3 yr - d(10 20 eV)<d GZK ~100Mpc !! No L>10 12 L sun at d<d GZK Transient Sources Gamma-ray Bursts (GRBs) ~ 10 2.5, L ~ 10 19 L Sun L/ 2 >10 12 L sun (dn/dVdt)*E~10 -9.5 /Mpc 3 yr *10 53.5 erg ~10 44 erg/Mpc 3 yr Transient: T ~10s << T p ~10 5 yr Active Galactic Nuclei (AGN, Steady): ~ 10 1 L>10 14 L Sun = few brightest !! Non at d<d GZK Invoke: * “ Dark ” (proton only) AGN * L~ 10 14 L Sun, t~1month flares (from stellar disruptions) [Blandford 76; Lovelace 76] [Waxman 95, Vietri 95, Milgrom & Usov 95] [Waxman 95] [Boldt & Loewenstein 00] [Farrar & Gruzinov 08]
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Anisotropy Cross-correlation signal: Inconsistent with isotropy @ 98% CL (~1.5 ) Consistent with LSS If anisotropy signal real & no anisotropy at 60EeV/(Z~10) primaries must be protons See M. Lemoine ’ s talk [arXiv:0907.1354] Biased ( source ~ gal for gal > gal ) [Kashti & Waxman 08]
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The GRB “ GZK sphere ” LSS filaments: D~1Mpc, f V ~0.1, n~10 -6 cm -3, T~0.1keV B =(B 2 /8 nT~0.01 (B~0.01 G), B ~10kpc Prediction: p D B [Waxman 95; Miralda-Escude & Waxman 96, Waxman 04]
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Summary Galactic <10 15 eV (<10 19 eV) - L G,CR ~10 -1.5 L G,SN & Max ~10 15 eV (10 19 eV) suggest SNR (trans-rel. SN) sources - TeV from low n, non-thermal X SNR: e - IC - Search for pp in high n, strong thermal X SNR pp:IC[@1GeV]~3 (n/1cm 3 ) * Anti-p, e + data consistent with 2 nd ary origin Prediction: e + /(e + + e-)<0.2+-0.1 up to ~300GeV PAMELA slightly rising f rad ( ) [constrain CR prop. Models] X-Galactic >10 19 eV - Likely protons, 2 (dQ/d ) ~10 43.7 erg/Mpc 3 yr, L B >10 12 L sun suggest: GRBs [AGN flares?] - Anisotropy constrains primary composition Difficult to uniquely identify sources via EM observations Search for HE ’ s
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Back up slides
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X-ray filaments Claim: X-ray filaments require B>100 G, much larger than required for IC explanation of TeV emission (B~10 G). Claim based on the assumption: Filaments due to e - cooling (vs, e.g., B variations). * No independent support to this assumption; * X-ray & RADIO filaments (Tycho, SN2006) inconsistent with this assumption.
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What is the e + excess claim based on? On assumptions not supported by data/theory * primary e - & p produced with the same spectrum, and e - and e+ suffer same f rad e + /e - ~ sec ~ -0.5 Or * detailed assumptions RE CR propagation, e.g. isotropic diffusion, D~ , within an -independent box f rad ~ ( -1)/2 If PAMELA correct, these assumptions are wrong
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(Correct) detailed CR propagation models must agree with simple, analytic results derived from sec Example: Diffusion models with {D~K 0 , box height L} reproduce data for parameter combinations shown in fig. [Maurin et al. 01] Trivial explanation: [Katz, Blum & Waxman 09] Require sec ( =35GeV) to agree with the value inferred from B/C sec =[3.2,3.45,3.9] g/cm 2 [green, blue, red]
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The 10 20 eV challenge R B v v 2R t RF =R/ c) l =R/ 22 22 [Waxman 95, 04, Norman et al. 95]
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Anisotropy clues: I Galaxy density integrated to 75Mpc CR intensity map ( source ~ gal ) [Waxman, Fisher & Piran 1997] Auger collaboration: Correlation with low-luminosity AGN @ 99% AGN? AGN trace LSS Correlation with large-scale structure? Unfortunately… Unclear.
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GRB proton/electron acceleration Electrons MeV ’ s: <1: e - ( ) spectrum: e - ( ) energy production [Waxman 95, 04] Afterglow, R GRB ~SFR Protons Acceleration/expansion: Synchrotron losses: Proton spectrum: p energy production: 52
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GRB Model Predictions [Miralda-Escude & Waxman 96]
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