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Cosmic-ray accelerators: What have we learned from IceCube’s neutrinos?

Cosmic-ray accelerators: What have we learned from IceCube’s neutrinos?. E. Waxman Weizmann Institute. arXiv:1312.0558 arXiv:1311.0287. Open Qs: The origin of CRs. Where is the G/XG transition?. log [dJ/dE]. E -2.7. Galactic. Protons. UHE X-Galactic. E -3. Source: Supernovae(?).

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Cosmic-ray accelerators: What have we learned from IceCube’s neutrinos?

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  1. Cosmic-ray accelerators:What have we learned from IceCube’s neutrinos? E. Waxman Weizmann Institute arXiv:1312.0558 arXiv:1311.0287

  2. Open Qs: The origin of CRs Where is the G/XG transition? 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]

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

  4. UHE: Energy production rate & spectrum cteff [Mpc] GZK Protons dQ/d log e =Const. • =0.5(+-0.2) x 1044 erg/Mpc3yr Mixed composition log(dQ/d log e) [erg/Mpc3yr] [Katz & EW 09] [Allard 12]

  5. Collisionless shock acceleration • The only predictive model. • No complete basic principles theory, but - Test particle + elastic scattering assumptions gives v/c<<1: dQ/d log e=Const., v/c~1: dQ/d log e=Const.xe-2/9 (G>>1, isotropic scattering), - Supported by basic principles plasma simulations, - dQ/d log e=Const Observed in a wide range of sources (lower energy p’s in the Galaxy, radiation emission from accelerated e-). [Krimsky77] [Keshet & EW 05] [Spitkovsky 06, Sironi & Spitkovsky 09, Keshet et al. 09, …] 200c/wp 40c/wp

  6. Intermediate energy: Neutrinos • 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]

  7. “Hidden” (n only) sources Violating UHECR bound BBR05

  8. Bound implications: >1Gton detector Fermi 2 flavors,

  9. IceCube: 37 events at 50Tev-2PeV ~6s above atmo. bgnd. A new era in n astronomy e2Fn=(2.85+-0.9)x10-8GeV/cm2sr s =e2FWB= 3.4x10-8GeV/cm2sr s Consistent with Isotropy and with ne:nm:nt=1:1:1 (pdeacy + cosmological prop.).

  10. IceCube’s detection: Implications • Unlikely Galactic: Isotropy, and e2Fg~10-7(E0.1TeV)-0.7GeV/cm2s sr [Fermi]  e2Fn ~10-9(E0.1PeV)-0.7GeV/cm2s sr << FWB • DM decay? The coincidence of 50TeV<E<2PeV n flux, spectrum (& flavor) with the WB bound is unlikely a chance coincidence. • XG distribution of sources, (dQ/d log e)PeV-EeV~(dQ/d log e) >10EeV, tgp(pp)>~1 [“Calorimeters”] • Or • (dQ/d log e)PeV-EeV>>(dQ/d log e) >10EeV, tgp(pp)<<1 • & Coincidence over a wide energy range. • (dQ/d log e)~ e0implies: p, G-XG transition at ~1019eV.

  11. Starburst galaxies: CR calorimeters • Radio, IR & g-ray (GeV-TeV) observations  Starbursts are calorimeters for E/Z reaching (at least) 10PeV. • Most of the stars in the universe were formed in Starbursts. • If CR sources reside in galaxies and Q~Star Formation Rate (SFR), Then Fn(en<1PeV)~FWB . [Loeb & EW 06]

  12. Low Energy, ~10GeV • Our Galaxy- using “grammage” • Starbursts- using radio to g observations • Q/SFRsimilar for different galaxy types, dQ/dloge ~Const. at all e! [Katz, EW, Thompson & Loeb 14]

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

  14. The cosmic ray generation spectrum A single source? MW CRs, Starbursts (+ CRs~SFR) XG n’s XG CRs [Katz, EW, Thompson & Loeb 14]

  15. Source candidates & physics challenges [Lovelace 76; EW 95, 04; Norman et al. 95] • Electromagnetic acceleration in astrophysical sources requires L>1014 LSun(G2/b) (e/Z 1020eV)2 erg/s • GRB: 1019LSun, MBH~1Msun, M~1Msun/s, G~102.5 AGN: 1014 LSun, MBH~109Msun, M~1Msun/yr, G~101 • No steady sources at d<dGZK  Transient Sources (AGN flares?), Charged CRs delayed compared to g’s. Energy extraction; Jet acceleration and content (kinetic/Poynting) Particle acceleration, Radiation mechanisms

  16. Identifying the sources • DQ~1deg  Identification by angular distribution impossible. • Our only hope: Identification of transient sources by temporal n-g association. • Requires: Wide field EM monitoring, Real time alerts for follow-up of high E nevents, and Significant increase of the n detector mass at ~100TeV [Fn(source) may be << Fn(calorimeter)~FWB[ e.g. Fn(GRB) ~0.1 FWB]].

  17. What will we learn from n-g associations? • Identify the CR sources. Resolve key open Qs in the accelerators’ physics (BH jets, particle acceleration, collisionless shocks). • Study fundamental/n physics: - p decay  ne:nm:nt = 1:2:0 (Osc.) ne:nm:nt = 1:1:1  t appearance, - GRBs: n-g timing (10s over Hubble distance)  LI to 1:1016; WEP to 1:106. • Optimistically (>100’s of n’s with flavor identification): Constrain flavor mixing, new phys. [Learned & Pakvasa 95; EW & Bahcall 97] [EW & Bahcall 97; Amelino-Camelia,et al.98; Coleman &.Glashow 99; Jacob & Piran 07] [Blum, Nir & EW 05; Winter 10; Pakvasa 10]

  18. Summary • IceCube detects extra-Galactic n’s. Fn=FWBat 50TeV-2PeV. • Flux & spectrum of ~1010GeV CRs, ~1PeV n(and ~10 GeV CRs) Consistent with CR p sources in galaxies, dQ/dloge~Const., Q~SFR. * IceCube’sdetection consistent with the predictedFn(en<1PeV)~FWB from sources residing in starbursts. [A flurry of models post-dictingIceCube’s results by arbitrarily choosing model parameters to match the flux, see Murase’s review.] * A single type of sources? • The sources are unknown. * UHE: L>1047(50)erg/s, GRBs or bright (to be detected) AGN flares. • Temporal n-g association is key to: CR sources identification, Cosmic accelerators’ physics, Fundamental/n physics.

  19. What is required for the next stageof the n astronomy revolution • The number of events provided by IceCube (~1/yr @ E>1 PeV, ~10/yr @ E>0.1PeV) will not be sufficient for an accurate determination of spectrum, flavor ratio and (an)isotropy. •  n telescopes Meff(100TeV) expansion to ~10Gton • (IceCube, Km3Net). • Wide field EM monitoring. • Adequate sensitivity for detecting the ~1010GeV GZK n’s.

  20. Backup Slides

  21. UHE, >1010GeV, CRs J(>1011GeV)~1 / 100 km2 year 2psr Auger: 3000 km2 3,000 km2 Fluorescence detector Ground array

  22. Where is the G-XG transition? e2(dQ/de) =Const @ E~1019eV @E<1018eV ? • Fine tuning • Inconsistent with Fermi’s XG g (<1TeV) flux [Katz & EW 09] [Gelmini 11]

  23. UHE: Do we learn from (an)isotropy? 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 Not observed  No high Z at 1019.7eV [Kashti & EW 08] [EW, Fisher & Piran 97] [Kotera & Lemoine 08; Abraham et al. 08… Oikonomouet al. 13] [Lemoine & EW 09]

  24. p production: p/A—p/g • p decay  ne:nm:nt = 1:2:0 (propagation) ne:nm:nt = 1:1:1 • p(A)-p: en/ep~1/(2x3x4)~0.04 (epeA/A); - IR photo dissociation of A does not modify G; - Comparable particle/anti-particle content. • p(A)-g: en/ep~ (0.1—0.5)x(1/4)~0.05; - Requires intense radiation at eg>A keV; - Comparable particle/anti-particle content, • ne excess if dominated by D resonance (dlogng/dlogeg<-1). [Spector, EW & Loeb 14]

  25. IceCube’s GRB limits • No n’s associated with ~200 GRBs (~2 expected). • IC analyses overestimate GRB flux predictions, • and ignore model uncertainties. • IC is achieving relevant sensitivity. [EW & Bahcall 97] [Hummer, Baerwald, and Winter 12; see also Li 12; He et al 12]

  26. Are SNRs the low E CR sources? • So far, no clear evidence. Electromagnetic observations- ambiguous. E.g.: “p decay signature” [Ackermann et al. 13]:

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