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The origin of Cosmic Rays: New developments and old puzzles

The origin of Cosmic Rays: New developments and old puzzles. K. Blum*, B. Katz*, A. Spector, E. Waxman Weizmann Institute *currently at IAS, Princeton. The cosmic ray spectrum. [From Helder et al., SSR 12]. log [dJ/dE]. E -2.7. Galactic. Protons. UHE X-Galactic. E -3.

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The origin of Cosmic Rays: New developments and old puzzles

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  1. The origin of Cosmic Rays:New developments and old puzzles K. Blum*, B. Katz*, A. Spector, E. Waxman Weizmann Institute *currently at IAS, Princeton

  2. The cosmic ray spectrum [From Helder et al., SSR 12]

  3. log [dJ/dE] E-2.7 Galactic Protons UHE X-Galactic E-3 Source: Supernovae(?) 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; Lemoine, J. Phys. 13]

  4. The cosmic ray generation spectrum

  5. UHE (>109.5 GeV=101.5 EeV)

  6. UHE: Composition Auger 2010 [Wilk & Wlodarczyk 10]* HiRes2010 (& TA 2011) HiRes 2005 [*Possible acceptable solution?, Auger collaboration 13]

  7. UHE: Anisotropy & Composition Biased (rsource~rgal for rgal>rgal ) CR intensity map (rsource~rgal) Galaxy density integrated to 75Mpc • Anisotropy @ 98% CL; Consistent with LSS • Anisotropy of Z at 1019.7eV implies Stronger aniso. signal (due to p) at (1019.7/Z) eV [since: Acceleration of Z(>>1) to E ~ Acceleration of p to E/Z, p(E/Z) propagation = Z(E) propagation, np>= nZ at the source.] Not observed  No high Z at 1019.7eV [Kashti & EW 08] [EW, Fisher & Piran 97] [Kotera & Lemoine 08; Abraham et al. 08… Foteini et al. 11] [Lemoine & EW 09]

  8. UHE: Flux & Generation Spectrum • e2(dN/de)Observed=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 [Katz & EW 09] • >1019.3eV: consistent with • protons, e2(dQ/de) =0.5(+-0.2) x 1044 erg/Mpc3 yr + GZK [EW 1995; Bahcall & EW 03]

  9. Intermediate E (106 GeV=1 PeV < E < 101.5 EeV)

  10. HE n: UHECR bound • p + g N +p p0 2g ; p+  e+ + ne + nm + nm  Identify UHECR sources Study BH accretion/acceleration physics • For all known sources,tgp<=1: • If X-G p’s:  Identify primaries, determine f(z) [EW & Bahcall 99; Bahcall & EW 01] [Berezinsky & Zatsepin 69]

  11. Bound implications: n experiments Fermi 2 flavors,

  12. IceCube (preliminary) detection • 28 events, compared to 12 expected, above 50TeV; ~4s • (cutoff at 2PeV?) • 1/E2 spectrum, 4x10-8GeV/cm2s sr • Consistent with ne:nm:nt=1:1:1 • Consistent with isotropy New era in n astronomy [N. Whitehorn, IC collaboration, IPA 2013]

  13. IceCube (preliminary) detection 2 flavors,

  14. IceCube’s detection: Some implications Isotropic, 1:1:1 flavor ratio, E2Fn~4x10-8GeV/cm2s sr~E2FWB @ 50TeV<E<2PeV • Unlikely Galactic: E2Fg~10-7(E0.1TeV)-0.7GeV/cm2s sr[Fermi]  ~10-9(E0.1PeV)-0.7GeV/cm2s sr • XG distribution of sources, • e2(dQ/de) >=0.5x 1044 erg/Mpc3 yr @ 106GeV< E <109GeV • p, e2(dQ/de)PeV-EeV~ e2(dQ/de) >10EeV, tgp(pp)>~1 • Or: • e2(dQ/de)PeV-EeV>> e2(dQ/de) >10EeV, tgp(pp)<<1 & Coincidence

  15. Low E (1GeV < E < 1TeV)

  16. Estimating the G-CR production rate • CR production in the Galactic disk: • Assuming CR production ~ SFR ~ SN rate, and using we have

  17. Galactic CR propagation models? • For all secondaries: • For positrons: At ~20GeV: frad~0.3~f10Be • Predictions for e+& p consistent with PAMELA & AMS observations. • Positron anomalies? • Due to assumptions adopted RE CR propagation. • Reflect the absence of a basic principles model. [Katz, Blum, Morag & EW 10; Blum Katz & EW 13] -

  18. Primary e+ sources Pulsars [Kashiyama et al. 11] DM annihilation [Hooper et al. 09]

  19. The cosmic ray generation spectrum Galactic CRs (+ CRs~SFR) XG n’s XG CRs

  20. Universal generation spectrum: Implications • Natural: All CRs produced in galaxies, Rate ~ SFR [Loeb & EW 02; Parizot 05; Aublin et al. 05] e2(dQ/de) =0.5(+-0.2) x 1044 erg/Mpc3yr • If so, Galactic CR density << than average @ E>107GeV  Transient sources, currently “dim state” • Implications/ Consistency checks: - Etransient> EGalaxy(>107GeV CRs)~1050.5+-1.5erg, consistent with strong explosions (SNe, GRBs) - Starburst nemission

  21. The 1020eV challenge v R B /G v G2 G2 2R l =R/G (dtRF=R/Gc) [Lovelace 76; EW 95, 04; Norman et al. 95]

  22. Source physics challenges • GRB: 1019LSun, MBH~1Msun, M~1Msun/s, G~102.5 • AGN: 1014 LSun, MBH~109Msun, M~1Msun/yr, G~101 • MQ: 105 LSun, MBH~1Msun, M~10-8Msun/yr, G~100.5 Jet acceleration [Reviws: GRBs Kouveliotou 94; Piran 05 AGN Begelman, Blandford & Rees 84 MQ HE: Aharonian et al 05; Khangulyan et al 07] Energy extraction Particle acceleration [Reviews: Lemoine 13; Kirk 08, 13] Jet content (kinetic/Poynting) Radiation mechanisms

  23. UHE: Bright transients [Lovelace 76; EW 95, 04; Norman et al. 95] • Electromagnetic acceleration in astrophysical sources requires L>LB>1046 (G2/b) (e/Z 1020eV)2 erg/s  No steady sources at d<dGZK  Transient Sources • If electrons are accelerated with protons, transients should also be bright in X-ray/g; The rate of such flares is much too low to account for the CR flux unless L> >1050 erg/s  >1050 erg/s flares or Inefficient e-acceleration (“dark flares”) [EW & Loeb 09]

  24. High energy n’s from Star Bursts • Starburst galaxies • {Star formation rate, density, B} ~ 103x Milky way Most stars formed in z>1.5 star bursts • CR e’s lose all energy to synchrotron radiation, CR p’s likely lose all energy to p production - If p’s lose all energy & radio bgnd dominated by starbursts: [Quataert et al. 06] Fn (~1GeV) Synchrotron radio calibration [Loeb & EW 06]

  25. M82 M81 Mark Westmoquette (University College London), Jay Gallagher (University of Wisconsin-Madison), Linda Smith (University College London), WIYN//NSF, NASA/ESA Robert Gendler

  26. Starburst galaxies: n emission [Loeb & EW 06] • Radio & nbgnd’s consistent with • e2(dQ/de)~1044erg/Mpc3yr in galaxies, ~SFR, tgp(pp)>~1

  27. Are SNRs the low E CR sources? • UHE, Intermediate E: Not yet identified • Low E- SuperNova Remnants? [Baade & Swicky 34] So far, no clear evidence [ Gallant’s talk]. Electromagnetic observations- ambiguous (e.g. TeV e- I.C. [Katz & EW 08; Butt et al. 08]). [e.g. Butt 09; Helder et al., SSR 12]

  28. Summary • The identity of the CR source(s) is still debated. • Many open Q’s RE candidate source(s) physics [accreting BHs]. • e2(dQ/de)~ 1044erg/Mpc3yr at all energies. Suggests: CRs of all E produced in galaxies@ a rate ~ SFR, by transients releasing ~1050.5+-1.5erg. • IceCube detects XG n’s, f~fWB at 50TeV—1PeV - A new era in n astronomy. - Consistent with the predictions of the ‘single source’ hypothesis, for tgp(pp)>~1in StarBursts.

  29. A new era in HE n’s • IceCube’s sensitivity meets the minimum requirements for detection of XG sources. • Preliminary detection of 50TeV-1PeV n’s. • Bright transients are the prime targets. • Coordinatedwidefield EM transient monitoring crucial: - Enhance n detection sensitivity, - Identify sources, Enable physics output. • XG n detection rate limited (<~10/yr). • Detection of a handful of n’s from EM identified sources may resolve outstanding puzzles: - Identify UHECR (& G-CR) sources, - Resolve open “cosmic-accelerator” physics Q’s (related to BH-jet systems, particle acc., rad. mechanisms), - Constrain n physics, LI, WEP.

  30. Back up slides

  31. Transient sources: GRB n’s • If: Baryonic jet • Background free: [EW & Bahcall 97, 99; Rachen & Meszaros 98; Guetta et al. 01; Murase & Nagataki 06]

  32. IceCube’s limits • IC40+59: No n’s for ~200 GRBs (~2 expected). • IC is achieving relevant sensitivity ! • IC analyses overestimate GRB flux predictions, • and ignore astrophysical uncertainties: [Hummer, Baerwald, and Winter 12; see also Li 12; He et al 12]

  33. G-XG Transition at ~1018eV? Inconsistent spectrum G cutoff @ 1019eV @ 1018eV: Fine tuning [Katz & EW 09]

  34. UHECR sources: Suspects • Constraints:- L>1012 (G2/b) Lsun,G > 102.5 (L52)1/10 (dt/10ms)-1/5 • - 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) • Lg~ 1019LSun>1012 (G2/b) Lsun= 1017 (G/ 102.5)2 Lsun • G~ 102.5 (L52)1/10 (dt/10ms)-1/5 • e2(dQ/de)g~ 1053erg*10-9.5/Mpc3 yr = 1043.5 erg/Mpc3 yr • Transient: DTg~10s << DTpg~105 yr • Active Galactic Nuclei (AGN, Steady): • G~ 101 L>1014LSun=few brightest • !! Non at d<dGZK  Invoke: • * “Hidden” (proton only) AGN • * L~ 1014LSun , Dt~1month flares • If e- accelerated: X/g observations  rare L>1017Lsun [EW 95, Vietri 95, Milgrom & Usov 95] [EW 95] [Blandford 76; Lovelace 76] [Boldt & Loewenstein 00] [Farrar & Gruzinov 08] [EW & Loeb 09]

  35. Bound implications: I. AGN n models “Hidden” (n only) sources Violating UHECR bound BBR05

  36. Single flavor Multi flavor [Anchordoqui & Montaruli 09]

  37. (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 & EW 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]

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