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What do we know about the identity of CR sources?

Explore an in-depth analysis on the identity of cosmic ray sources based on research by Boaz Katz, Kfir Blum, and Eli Waxman from Weizmann Institute, Israel. Gain insights into the cosmic ray spectrum, composition, galactic and extra-galactic sources, energy production rates, and more. Discover the implications for Fermi, TeV observations and the potential origins of cosmic rays. This comprehensive overview delves into the complexities of cosmic rays, from Galactic Protons to likely Supernovae sources and beyond.

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What do we know about the identity of CR sources?

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  1. What do we know about theidentity of CR sources? Boaz Katz, Kfir Blum Eli Waxman Weizmann Institute, ISRAEL

  2. The cosmic-ray spectrum & Composition log [dJ/dE] E-2.7 Galactic Protons E-3 Source: Supernovae(?) X-Galactic (?) Heavy Nuclei Source? Light Nuclei? Lighter Source? 1 1010 106 Cosmic-ray E [GeV] [Blandford & Eichler, Phys. Rep. 87; Axford, ApJS 94; Nagano & Watson, Rev. Mod. Phys. 00]

  3. 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)

  4. Galactic CR sources: Constraints • Max e>~1015eV • Energy production rate LG,CR~(AdiskhCR)UCR/tCR * UCR~1 eV/cm3, * Propagation: 2nd-ary (& primary) composition  LG,CR~cAdiskUCR(Sdisk/Ssec)~1049.5erg/100yr [Blandford & Eichler, Phys. Rep. 87; Axford, ApJS 94]

  5. Galactic CR sources: SNe? • Motivation for SNe as sources: * LG,CR~10-1.5LG,SN * Max e~1015eV * e- acceleration to 1015eV 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]

  6. TeV must be due to e- IC • ppp origin in contradiction with radio, thermal-X (non detection of thermal X n<~0.1/cm3): • TeV consistent with e- IC, including “cutoffs”: • Claims RE e- IC inconsistency: Detailed spectral shape near hnc, where theoretical predictions are highly uncertain [Katz & Waxman 07]

  7. 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]

  8. PAMELA: New e+ sources? • Apply  anti-p, e+ consistent with 2ndary origin • Radiative e+ losses- depend on propagation in Galaxy (poorly understood) * At 20GeV: frad~0.3~f10Be * Above 20GeV: If PAMELA correct  slightly rising frad(e) [Katz, Blum & Waxman 09]

  9. What do we know about >1019eV CRs? [Waxman 95, 04] • Max e: LB>1012 (G2/b) (e/Z 1020eV)2 Lsun (see Dermer’s talk) • Composition

  10. Composition clues HiRes 2005

  11. Westerhoff (Auger) 2009

  12. What do we know about >1019eV CRs? • Max e: LB>1012 (G2/b) (e/Z 1020eV)2 Lsun • Composition: HiRes –protons, Auger- becoming heavier @ 3x1019eV? !!Uncertain interaction cross sections • Energy production rate: - LB>1012 Lsun & RL=e/eB=40ep,20kpc  Likely X-Galactic

  13. Flux & Spectrum • e2(dN/de)=e2(dQ/de) teff. (teff. : p + gCMB N +p) • Assume: p, dQ/de~(1+z)me-a log(e2dQ/de) [erg/Mpc2 yr] cteff [Mpc] GZK (CMB) suppression • >1019.3eV: consistent with • protons, e2(dQ/de) ~1043.7 erg/Mpc3 yr + GZK • e2(dQ/de) ~Const.: Consistent with shock acceleration [Katz & Waxman 09] [Waxman 1995; Bahcall & Waxman 03] [Reviews: Blandford & Eichler 87; Waxman 06 cf. Lemoine & Revenu 06]

  14. G-XG Transition at 1018eV? Inconsistent spectrum Fine tuning [Katz & Waxman 09]

  15. What do we know about >1019eV CRs? • Max e: LB>1012 (G2/b) (e/Z 1020eV)2 Lsun • Composition HiRes –protons, Auger- becoming heavier Uncertain interaction cross sections • Energy production rate - LB>1012 Lsun & RL=e/eB=40ep,20kpc  Likely X-Galactic - Consistent with protons, e2(dQ/de) ~1043.7 erg/Mpc3 yr + GZK

  16. UHE CR sources • Constraints:- L>1012 (G2/b) Lsun • - e2(dQ/de) ~1043.7 erg/Mpc3 yr • - d(1020eV)<dGZK~100Mpc • !! No L>1012 Lsun at d<dGZK  Transient Sources • Gamma-ray Bursts (GRBs) • G~ 102.5, Lg~ 1019LSun L/G2 >1012 Lsun • (dn/dVdt)*E~10-9.5 /Mpc3 yr *1053.5erg ~1044 erg/Mpc3 yr • Transient: DTg~10s << DTpg ~105 yr • Active Galactic Nuclei (AGN, Steady): • G~ 101 L>1014 LSun=few brightest • !! Non at d<dGZK  Invoke: • * “Dark” (proton only) AGN • * L~ 1014 LSun , Dt~1month flares • (from stellar disruptions) [Waxman 95, Vietri 95, Milgrom & Usov 95] [Waxman 95] [Blandford 76; Lovelace 76] [Boldt & Loewenstein 00] [Farrar & Gruzinov 08]

  17. Anisotropy Biased (rsource~rgal for rgal>rgal ) • Cross-correlation signal: Inconsistent with isotropy @ 98% CL (~1.5s) 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] [Kashti & Waxman 08]

  18. The GRB “GZK sphere” g p • LSS filaments: D~1Mpc, fV~0.1, n~10-6cm-3, T~0.1keV eB=(B2/8p)/nT~0.01 (B~0.01mG), lB~10kpc • Prediction: D lB [Waxman 95; Miralda-Escude & Waxman 96, Waxman 04]

  19. Summary • Galactic e<1015eV (<1019eV) - LG,CR~10-1.5LG,SN & Max e~1015eV (1019eV) 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/1cm3) * Anti-p, e+ data consistent with 2ndary origin Prediction: e+/(e++ e-)<0.2+-0.1 up to ~300GeV PAMELA slightly rising frad(e) [constrain CR prop. Models] • X-Galactic e>1019eV - Likely protons, e2(dQ/de) ~1043.7 erg/Mpc3 yr, LB>1012 Lsun  suggest: GRBs [AGN flares?] - Anisotropy constrains primary composition • Difficult to uniquely identify sources via EM observations  Search for HE n’s

  20. Back up slides

  21. X-ray filaments • Claim: X-ray filaments require B>100mG, much larger than required for IC explanation of TeV emission (B~10mG). • 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.

  22. 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 frad  e+/e-~Ssec~e-0.5 Or * detailed assumptions RE CR propagation, e.g. isotropic diffusion, D~ed, within an e-independent box  frad ~e(d-1)/2 • If PAMELA correct, these assumptions are wrong

  23. (Correct) detailed CR propagation models must agree with simple, analytic results derived from Ssec • Example: Diffusion models with {D~K0ed, box height L} reproduce data for parameter combinations shown in fig. [Maurin et al. 01] • Trivial explanation: • [Katz, Blum & Waxman 09] • Require • Ssec(e =35GeV) • to agree with the value inferred from B/C • Ssec =[3.2,3.45,3.9] g/cm2 • [green, blue, red]

  24. The 1020eV challenge v R B /G v G2 G2 2R l =R/G (dtRF=R/Gc) [Waxman 95, 04, Norman et al. 95]

  25. Anisotropy clues: I CR intensity map (rsource~rgal) Galaxy density integrated to 75Mpc • Auger collaboration: Correlation with low-luminosity AGN @ 99%  AGN? • AGN trace LSS Correlation with large-scale structure? • Unfortunately… Unclear. [Waxman, Fisher & Piran 1997]

  26. Electrons MeV g’s: tgg<1: e- (g) spectrum: e- (g)energy production Protons Acceleration/expansion: Synchrotron losses: Proton spectrum: p energy production: GRB proton/electron acceleration 52 Afterglow, RGRB~SFR [Waxman 95, 04]

  27. GRB Model Predictions [Miralda-Escude & Waxman 96]

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