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

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Presentation on theme: "High Energy Neutrinos from Astrophysical Sources Dmitry Semikoz UCLA, Los Angeles & INR, Moscow."— Presentation transcript:

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

2 Neutrino Oscillation Workshop, September 16, 2004 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

3 Neutrino Oscillation Workshop, September 16, 2004 INTRODUCTION

4 Neutrino Oscillation Workshop, September 16, 2004 Conditions required for production of high energy neutrinos in astrophysical sources: Acceleration of charged particles (protons or nuclei) to high energies E>10 15 eV Accelerated particles should lose energy through pion production or neutron decay Obey gamma-ray and neutrino flux limits

5 Neutrino Oscillation Workshop, September 16, 2004 Neutrinos from pion production p n Conclusion: photon and neutrino fluxes are connected in well-defined way. If we know one of them we can predict other:

6 Neutrino Oscillation Workshop, September 16, 2004 High energy photons from pion decay cascade down in GeV region

7 Neutrino Oscillation Workshop, September 16, 2004 The high energy gamma ray detector on the Compton Gamma Ray Observatory (20 MeV - ~20 GeV) EGRET: gamma-ray flux

8 Neutrino Oscillation Workshop, September 16, 2004 Photon flux at E>100 MeV as measured by EGRET till 1995 The Flux of Diffuse Photons Point sources

9 Neutrino Oscillation Workshop, September 16, 2004 The next-generation ground-based and space-based experiments are well matched. Complementary capabilities ground-based space-based ACTEAS Pair angular resolutiongoodfair good duty cyclelowhigh high arealargelarge small field of viewsmalllarge large +can reorient energy resolutiongoodfair good, w/ smaller systematic uncertainties High energy gamma ray experiments

10 Neutrino Oscillation Workshop, September 16, 2004 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 Neutrino Oscillation Workshop, September 16, 2004 Diffuse flux of neutrinos

12 Neutrino Oscillation Workshop, September 16, 2004 Cosmic rays and AGNs Diffused flux from cosmic rays Many unresolved sources AMANDA II

13 Neutrino Oscillation Workshop, September 16, 2004 GLAST: sources LAT 1 st Catalog: >9000 sources possible

14 Neutrino Oscillation Workshop, September 16, 2004 AGN as neutrino sources

15 Neutrino Oscillation Workshop, September 16, 2004 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 Neutrino Oscillation Workshop, September 16, 2004 Can sources accelerate protons to such high energies? AGASA data E> eV: AGNs are one of most probable sources

17 Neutrino Oscillation Workshop, September 16, 2004 Neutrino production in AGN core

18 Neutrino Oscillation Workshop, September 16, 2004 Neutrinos from AGN core AMANDA II J.Alvarez-Muniz and P.Mezsaros, astro-ph/

19 Neutrino Oscillation Workshop, September 16, 2004 Most probable point-like neutrino sources

20 Neutrino Oscillation Workshop, September 16, 2004 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 Neutrino Oscillation Workshop, September 16, 2004 Most probable single sources- AGN Blazars GeV-loud Optical depth for protons should be large:  p  n  R  Only 22 sources from 66 are GeV - loud

22 Neutrino Oscillation Workshop, September 16, 2004 TeV blazars does not obey last condition Indeed, in order TeV blazars be a neutrino sources:   p  n  R     n  R    p  = 6x cm 2 while for TeV gamma-rays   = 6.65 x cm 2 CONTRADICTION!!! Except if proton background density is as high as photon one, because  pp  = 6x cm 2 This is unlikely in BL Lacs, where emission lines are absent.

23 Neutrino Oscillation Workshop, September 16, 2004 Which sources ? Blazars (angle – energy correlation) Blazars should be GeV loud Optical depth for protons should be large:  p  n  R  No kpc scale jet detected (model-dependent)

24 Neutrino Oscillation Workshop, September 16, 2004 Neutrino production in AGN

25 Neutrino Oscillation Workshop, September 16, 2004 Bound on blazars which can be a neutrino sources A.Neronov, D.S., 2002

26 Neutrino Oscillation Workshop, September 16, 2004 Collimation of neutrino flux in compare to GeV flux AMANDA II

27 Neutrino Oscillation Workshop, September 16, 2004 Galaxy center: cosmic rays AGASA experiment see anisotropy towards the Galactic center. This signal can be explained by neutrons.

28 Neutrino Oscillation Workshop, September 16, 2004 Galaxy center Cosmic ray neutrons decay on the way and produce neutrinos. L.Archadoqui, H.Holdberg, F.Halzen and T.Weiler, astro-ph/

29 Neutrino Oscillation Workshop, September 16, 2004 Microquasars AGN on star scales. Protons are accelerated by shock wave up to eV In interaction with X- ray photons from accretion disk protons produce TeV neutrinos A.Levinson and E.Waxman, 2001 C.Distefano et al, 2002

30 Neutrino Oscillation Workshop, September 16, 2004 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/ ) Extra 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/ ) Supernova 1987A 23 February 1987

31 Neutrino Oscillation Workshop, September 16, 2004 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 km 2 detectors.


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