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High Energy Neutrinos from Astrophysical Sources

High Energy Neutrinos from Astrophysical Sources

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High Energy Neutrinos from Astrophysical Sources

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  1. High Energy Neutrinos from Astrophysical Sources Dmitry Semikoz UCLA, Los Angeles & INR, Moscow

  2. Overview: • Introduction: cosmic rays, gamma-rays and neutrinos • Diffuse neutrino fluxes • Neutrinos from UHECR (Friday, F.Halzen , G.Miele) • Neutrinos from AGN • Most probable point-like neutrino sources • AGN • Galaxy center • Microquasars • SuperNova high energy E>TeV neutrinos • GRB (Friday, P.Meszaros) • Conclusion


  4. Conditions required for production of high energy neutrinos in astrophysical sources: • Acceleration of charged particles (protons or nuclei) to high energies E>1015 eV • Accelerated particles should lose energy through pion production or neutron decay • Obey gamma-ray and neutrino flux limits

  5. Neutrinos from pion production n p Conclusion: photon and neutrino fluxes are connected in well-defined way. If we know one of them we can predict other:

  6. High energy photons from pion decay cascade down in GeV region

  7. EGRET: gamma-ray flux The high energy gamma ray detector on the Compton Gamma Ray Observatory (20 MeV - ~20 GeV)

  8. Photon flux at E>100 MeV as measured by EGRET till 1995 Point sources The Flux of Diffuse Photons

  9. High energy gamma ray experiments Complementary capabilities ground-based space-based ACTEASPair angular resolution good fair good duty cycle low high high area large large small field of view small large large+can reorient energy resolution good fair good, w/ smaller systematic uncertainties The next-generation ground-based and space-based experiments are well matched.

  10. EGRET flux can consist of: • Inverse Compton scattered photons • Synchrotron photons from high energy protons • Photons from pion decay, which cascade down in intergalactic space or in source • Thus EGRET flux give just upper limit on diffuse or point source neutrino flux

  11. Diffuse flux of neutrinos

  12. Cosmic rays and AGNs Diffused flux from cosmic rays Many unresolved sources AMANDA II

  13. GLAST: 10000 sources LAT 1st Catalog: >9000 sources possible

  14. AGN as neutrino sources

  15. Only few classes of astrophysical objects are able to accelerate particles to highest energies • For neutrino production we have to look for the sources with high density of background photons or protons

  16. Can sources accelerate protons to such high energies? AGASA data E> 1019 eV: AGNs are one of most probable sources

  17. Neutrino production in AGN core

  18. Neutrinos from AGN core AMANDA II J.Alvarez-Muniz and P.Mezsaros, astro-ph/0409034

  19. Most probable point-like neutrino sources

  20. Point source fluxes • Background of atmospheric neutrinos against flux of given source. Position of source given a priori. • AMANDA II 1.8 degrees resolution: 3 background 6 observed • ANTARES 0.3 degrees • ICECUBE 0.5 degrees • KM^3 0.3 degrees<

  21. Most probable single sources- AGN • Blazars • GeV-loud • Optical depth for protons should be large: t = spg ng R>>1 Only 22 sources from 66 are GeV - loud

  22. TeV blazars does not obey last condition • Indeed, in order TeV blazars be a neutrino sources: • = spg ng R>>1 • = sgg ng R <<1 spg = 6x10-28cm2while for TeV gamma-rays sgg = 6.65 x 10-25cm2 • CONTRADICTION!!! Except if proton background density is as high as photon one, because spp= 6x10-26cm2 This is unlikely in BL Lacs, where emission lines are absent.

  23. Which sources ? • Blazars (angle – energy correlation) • Blazars should be GeV loud • Optical depth for protons should be large: t = spg ng R>>1 • No 100 - kpc scale jet detected (model-dependent)

  24. Neutrino production in AGN

  25. Bound on blazars which can be a neutrino sources A.Neronov, D.S., 2002

  26. Collimation of neutrino flux in compare to GeV flux AMANDA II

  27. Galaxy center: cosmic rays • AGASA experiment see anisotropy towards the Galactic center. • This signal can be explained by neutrons.

  28. Galaxy center • Cosmic ray neutrons decay on the way and produce neutrinos. L.Archadoqui, H.Holdberg, F.Halzen and T.Weiler, astro-ph/0311002

  29. Microquasars • AGN on star scales. • Protons are accelerated by shock wave up to 1016 eV • In interaction with X-ray photons from accretion disk protons produce 1-100 TeV neutrinos A.Levinson and E.Waxman, 2001 C.Distefano et al, 2002

  30. Supernova 1987A 23 February 1987 Galactic SN • When shock came out of star it start to accelerate protons. • Up to 200 events with E>1 TeV in ICECUBE within few hours (E.Waxman and A.Loeb, astro-ph/0102317) • Extra 1000-10000 events in first year (V.Berezinsky and V.Ptuskin, 1988) • Can help to detect SN location up to 0.1 degree. (R.Tomas, D.S., G.Raffelt, M.Kachelriess and A.Dighe, hep-ph/0307050)

  31. Conclusions • Diffuse neutrino flux can be combination of cosmic ray and AGN neutrinos. • GeV-loud blazars with high optical depth for protons are good candidates for point-like neutrino sources. • Galaxy center can be good source of neutrinos and flux can be predicted based on AGASA signal. • Galactic microquasars, GRB, galactic SN are sources of neutrinos. • We have a good chance to detect those sources with km2 detectors.