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Nearby sources in the transition region between Galactic and Metagalactic cosmic rays

L. G. Sveshnikova1 , O. N. Strelnikova, L. A. Kuzmichev, V.S. Ptuskin, V.A. Prosin, E.Korosteleva et al. Nearby sources in the transition region between Galactic and Metagalactic cosmic rays.

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Nearby sources in the transition region between Galactic and Metagalactic cosmic rays

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  1. L. G. Sveshnikova1 , O. N. Strelnikova, L. A. Kuzmichev, V.S. Ptuskin, V.A. Prosin, E.Korosteleva et al Nearby sources in the transition region between Galactic and Metagalactic cosmic rays

  2. Amazing fine structure in the range 10^16-10^18eV and highcontent of Fe around 10^17 eV eV in Tunka 133 and Kascade Grande Is it possible to indicate the sources giving the main contribution around the transition region 10^17- 510^18 eV? What can we say about source spectrum and birthrate and candidates. Sveshnikova L. G., Strelnikova O. N., Ptuskin V. S.OnprobablecontributionofnearbysourcestoanisotropyandspectrumofcosmicraysatTeV-PeV-energies, Procof 32 ICRC, Beijing, China, 2011, N 1057, 4p.

  3. Basic MODEL of composition and Emax of Galactic sources at high energies: • Type IIP SNRs • (Emax~0.1Z PeV) <100 TeV • Type Ia SNRs • (Emax~4Z PeV). • Type Ib/c SNRs (Emax~1Z PeV) • Type IIb SNRs • (Emax~600Z PeV) 3-5% sources are spread continuously in space and time SSЫ V.Ptuskin, V.Zirakashvili, andEun-SukSeo,Spectrumofgalacticcosmicraysacceleratedinsupernovaremnants. Astrophysical J. T. 718 p. 31–36. 2010 Pmax/Z ∼ 1 × 1015×E51×n1/6M−2/3ej

  4. Nearby sources from gamma-catalogs 3 kpc

  5. In our model knee is provided:1)group of sources with close parameters of explosions and Emax: only SNIa –”standard candles” – is suited for this aim2) Additional condithion : the sharp cutoff in sources spectrum ~dg ~ 2 Zirakashvili, V.N and Ptuskin, V.S.), Proc of 32 ICRC, Beijing, 2011, Zirakashvili, V.N., Aharonian, F.A., 2010, arXive: 1011.4775

  6. We can directly obtain the chemical composition around the knee if we suppose the 1)regidity dependent Emax~ZEmax(pr), 2)nearly same slopes for species, then we drow parallel lines Nearly “normal” composition P+He(~70%) CNO(10%) Si-Ca(~10%),Fe (~15-25%)–small excess of Fe

  7. If we subtract the contribution of knee, how much is left over?

  8. The sharp knee with slope g ~1.7+-0.2 and • dg~2 (not 0.5) • 2) Large dg means light composition: • P (70%),He(25%), +CNO(1.5%),Si-Ca (1.5%), Fe (1%) • 3) We expect significant contribution from one sources, because we could not imagine the class of sources with fixed Emax, due to large diversity of SNR properties First interpretation : Galactic sources : Expected source spectrum .

  9. There is an optimal distance and time to reach the Earth for CR ~ 10^17 eV

  10. How many sources we expectand where should be the closest one?It depends on birthrate If birthrate of sources (accelerated to 2E17) 1-3% from all, then the total number ~1-3 sources within the distance 3 kpc from Earth and younger 100 ky The closest sources most probably is located at 2-4 kpc

  11. Contribution of real nearby sources if they emits the same number of cosmic rays as an average SNR. Young Galactic SNRs (R~ 2-3 kpc, T~0.5-1.5 ky) – the best candidates, Everyone from them can provides the CR in the region 10^17-510^18 эВ . One evident problem!!! We should see this source in gamma rays with very large shock velocity, with very large turbulent magnetic field at the shock front , small ejected mass,

  12. Cas A – very good candidate • Many unusual properties from (J. Vink. arXiv:1112.0576v2 ) J • 1. An important class of SNRs are the so-called oxygen-rich SNRs. Chevalier and Oishi (2003) : Cas A must have been a Type IIb SNR, similar to SN1993J • Progenitor main sequence mass of 18±2M⊙. • 4. Strong bipolarity referred to as “the jet”. • 5. Best explained with a binary star scenario, in which a high mass loss is caused by a common envelope phase. • 6. In Cas A many iron-rich knots, indicate that the mean velocity of these iron knots are higher than 7000 kms−1.

  13. Main Signatures of this hypothesis: • Chemical composition around 1018 should be lnA ~2 - not lighter • Very high anisotropy at 2 10^17-5 10^18

  14. Alternative explanation (If Metagalactic CR) “Inhomogeneous extragalactic magnetic fields and the second knee in the cosmic ray spectrum”. K. Kotera and M. Lemoine arXiv:0706.1891v2 [astro-ph] 4 Jan 2008 Variant :Bo=2nG, lc=100 kpc, n=1-^-5 Mpc-3

  15. It is easy to obtain some bumpor peak at the boundary between Galactic and Metagalactic CR Galactic CR- Meta Galactic CR signature

  16. Main signatures: FePr at 2 10^17 эВVery low anisotropy at E>2 10^ 17

  17. I )Conclusion: if Galactic sources provide CR between CR in 10^17-410^18: • 1) Sources spectrum:  ~ 1.7-2.01, • Emax ~ z(23)1017 , • very light composition P+He~95%, Fe<2% • 2) Closest sources should be at distance ~2-4 kpc, T < 100 ky • 3) One source with usual power is enough, may be Cas A???

  18. II.ConclusionGalacticMetagalactic at 10^17 eV • The variant Galactic Metagalactic CR at 10^17 eV does not contradict to calculations with magnetic horizon • and to chemical composition measured in Hires and Telescope array, • and even it is possible to get a bump or peak at the boundary.

  19. Conclusions 3 • The fine structure and the high content of Fe around 1017 eV can be reproduced in the model if class of sources SNIa (standard candles in cosmology, birthrate ~20% from all) with Emax ~4 PeV and chemical composition P+He~ 60%, Fe~15-25~%, d~2 in source.

  20. Тhank you

  21. Contribution of nearby sourcesaround the knee • We could not exclude the “single source” • But only Vela Jr. can provide the structure around the knee and only if : • Emax=F(Temission) • D~0.3 kpc, T~0.7 ky • It’s very difficult to obtained high Fe content around 10^17 eV. • Background sources also must have high Fe content!!!

  22. “Single source “ • III. Only one sources -Vela Jr – if it is very young and close if (R~0.3-0.5 kpc, T~0.7-1.7 ky,) is suited to the “single source” determining the “sharpness” of the knee, • But • the background also should be abundant with by Fe nuclei in the region 10^17 ev, that in their turn means the rigidity dependent knee around 4 PeV for background sources also.

  23. Zirakashvili, V.N and Ptuskin, V.S.), Proc of 32 ICRC, Beijing, 2011, Role of reverse shocks for the production of galactic cosmic rays in SNRs Zirakashvili, V.N., Aharonian, F.A., 2010, arXive: 1011.4775

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