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Latest upper limits on neutrino fluxes from point-like sources with AMANDA-II

http://icecube.wisc.edu. Latest upper limits on neutrino fluxes from point-like sources with AMANDA-II. Markus Ackermann for the IceCube collaboration Markus.Ackerman@desy.de DESY. Outline. I The AMANDA-II point source search II Results from the analysis of 1001 effective days of data

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Latest upper limits on neutrino fluxes from point-like sources with AMANDA-II

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  1. http://icecube.wisc.edu Latest upper limits on neutrino fluxes from point-like sources with AMANDA-II Markus Ackermann for the IceCube collaboration Markus.Ackerman@desy.de DESY The multimessenger approach to high energy gamma ray sources, Barcelona, 04.07.06-07.07.06

  2. Outline I The AMANDA-II point source search II Results from the analysis of 1001 effective days of data (2000-2004) III Comparison of upper limits to a selection of predicted neutrino fluxes IV Summary The multimessenger approach to high energy gamma ray sources, Barcelona, 04.07.06-07.07.06

  3. 677 Optical Modules AMANDA-II AMANDA 90º S IceCube The multimessenger approach to high energy gamma ray sources, Barcelona, 04.07.06-07.07.06

  4. On-Source = 2.25° - 3.75° Off-Source Search for point sources • Search for signal from candidate sources • Scan of full northern sky • Stacked search of generic source classes • Atm-n Background from ‘off-source’ data  only statistical error ~ 7% • Flux upper limits by comparison to signal simulation The multimessenger approach to high energy gamma ray sources, Barcelona, 04.07.06-07.07.06

  5. tau neutrinos via nt t m + nt+ nm (17.7 %) Neutrino effective areas muon neutrinos The multimessenger approach to high energy gamma ray sources, Barcelona, 04.07.06-07.07.06

  6. Sensitivity • Sensitivity to neutrino flux dF/dE ~ E-2 • Contribution of nt to sensitivity 10-16% (declination dependent) • nm + nt is the strongest limit on the neutrino flux for a nm:nt = 1:1 flavor ratio E2 dF/dE [10-7 GeV cm-2 s-1] The multimessenger approach to high energy gamma ray sources, Barcelona, 04.07.06-07.07.06

  7. Results I: Candidate sources • 32 sources in candidate list • No significant excess, no indication for a neutrino source • Systematic error of 15% on signal prediction included in limits AGN Microquasar SNR The multimessenger approach to high energy gamma ray sources, Barcelona, 04.07.06-07.07.06

  8. Results II: Grid search Significance / s 2000-2004 Largest fluctuation: 3.7s at 12.6 h, +4.5 deg Random events 69 out of 100 sky maps with randomized events show an excess higher than 3.7s The multimessenger approach to high energy gamma ray sources, Barcelona, 04.07.06-07.07.06

  9. Limit map • 90% confidence level flux upper limits for the northern hemisphere in 0.5 deg bins (15% systematic error included) The multimessenger approach to high energy gamma ray sources, Barcelona, 04.07.06-07.07.06

  10. Source stacking analysis • Search for an excess of events from several sources combined • AGNs grouped in classes of potential high energy neutrino sources • Assumption: neutrino flux is linearly correlated with luminosity Flux upper limit in units of 10-7 GeV cm-2s-1 for differential flux dF/dE ~ E-2 A. Gross, Ph.D thesis, University of Dortmund Achtenberg et al., “On the selection of AGN …”, Accepted by Astropart. Phys. The multimessenger approach to high energy gamma ray sources, Barcelona, 04.07.06-07.07.06

  11. Comparison to selected models dF/dE ~ E-3 dF/dE ~ E-2 dF/dE ~ E-1 • Specific theoretical models for neutrino emission from a single source rarely show a pure E-2 spectrum • Variation of the spectral index between g=1 and g=3 shifts the peak energy of the detected neutrinos by 6 orders of magnitude • Specific limits have to be calculated for the sources/spectra modelled based on the effective area of AMANDA-II The multimessenger approach to high energy gamma ray sources, Barcelona, 04.07.06-07.07.06

  12. Sensitivity to different spectra Sensitivity to dF/dE ~ E-3: Declination dependence from detector efficiency E3 dF/dE [10-3 GeV2 cm-2 s-1] E dF/dE [10-13 cm-2 s-1] Sensitivity to dF/dE ~ E-1 : Declination dependence due to neutrino absorption The multimessenger approach to high energy gamma ray sources, Barcelona, 04.07.06-07.07.06

  13. Guetta & Amato: Rescaling of gamma ray flux (Nn,exp=0.16) Bednarek & Protheroe: Heavy nuclei accelerated in outer gap (Nn,exp=0.08) Bednarek: Time evolution of pulsar wind nebula (Nn,exp=0.03) Link & Burgio: Ions accelerated near pulsar surface (Nn,exp=1.2) Crab nebula Flux limits and predictions shown correspond to nm+nt flux on earth for a flavor ratio of nm:nt = 1:1 The multimessenger approach to high energy gamma ray sources, Barcelona, 04.07.06-07.07.06

  14. Distefano et al.: pg-interaction in the jet with int. and ext. photons (Nn,exp=7.8) Bednarek: pp-interaction in WR star and accretion disk after photodissoziation of heavy nuclei in the jet (Nn,exp=2.1 / 1.4) Anchordoqui et al.: Protons accelerated in electrostatic gap interact in accretion disk (Nn,exp=0.12) X-ray binaries The multimessenger approach to high energy gamma ray sources, Barcelona, 04.07.06-07.07.06

  15. Protheroe et al.: M87 is considered a misaligned BLLac object in the Proton Synchrotron Blazar model (Muecke et al. 2002) Nn,exp= 0.06 (LBL) Nn,exp= 6 10-4 (HBL) Protheroe et al. LBL (2004) Protheroe et al. HBL (2004) M87 The multimessenger approach to high energy gamma ray sources, Barcelona, 04.07.06-07.07.06

  16. Neronov and Semikoz: Model for “typical GeV loud Blazar”, pg-interaction in the AGN core Nn,exp= 0.04 - 1.1(QSO 0528+134) Nn,exp= 0.006 – 0.14(QSO 0954+556) EGRET Blazars variation of beaming angle for n-emission The multimessenger approach to high energy gamma ray sources, Barcelona, 04.07.06-07.07.06

  17. Summary and Outlook • 5 years of data (1001 effective days) of the AMANDA-II detector have been analyzed for a signal from neutrino point sources. • No statistically significant source of neutrinos has been found so far. • The analysis provides the most stringent limits on neutrino fluxes from point sources on the northern hemisphere. • Current models of neutrino emission from Microquasars can be constrained by the results. • From the end of 2007 IceCube will improve the limits beyond the reach of AMANDA-II . The multimessenger approach to high energy gamma ray sources, Barcelona, 04.07.06-07.07.06

  18. BACKUP SLIDES The multimessenger approach to high energy gamma ray sources, Barcelona, 04.07.06-07.07.06

  19. Neutrino effective area nm (2000-2004) The multimessenger approach to high energy gamma ray sources, Barcelona, 04.07.06-07.07.06

  20. extraterrestrial neutrinos few events expected Atmospheric neutrinos  103 events / year d > 0º d < 0º Cosmic rays Muons from air showers  109 events / year Neutrino event selection - • „Blind“ event selection to avoid statistical biases • Selection optimized for hard and soft spectra The multimessenger approach to high energy gamma ray sources, Barcelona, 04.07.06-07.07.06

  21. Systematics • Main contributions the systematic error of the point source analysis are • average OM sensitivity (~ 10%) • rock density ( up to 7%) • detector simulation inaccuracies (~ 7 %) • Uncertainty of average OM sensitivity can be strongly constrained from zentith distribution of atmospheric neutrinos (30%  10 %) • Total systematic uncertainty on the signal efficiency • E-2 spectrum: +10 / -15 % • E-3 spectrum: +5 / -20 % • atmos. spectrum: +5 / -25 % The multimessenger approach to high energy gamma ray sources, Barcelona, 04.07.06-07.07.06

  22. Systematics summary II • Zenith distribution of events in the point source sample • Predictions from atmospheric neutrino simulation is shown with its systematic error interval The multimessenger approach to high energy gamma ray sources, Barcelona, 04.07.06-07.07.06

  23. Nellen et al.: pp interaction in AGN core (Nn,exp= 0.86) Stecker and Salamon: pg interaction in AGN core (Nn,exp= 0.81) Mannheim: pp and pg interaction in the Blazar jet (Nn,exp= 0.01) Diffuse flux predicitons from Nellen et al. and Stecker and Salamon already excluded by AMANDA-II limits 3C273 The multimessenger approach to high energy gamma ray sources, Barcelona, 04.07.06-07.07.06

  24. Muecke et al.: Model of Markarian 421 as High frequency peaked BLLac in the Proton Synchrotron Blazar model (Nn,exp~ 0 ) Markarian 421 The multimessenger approach to high energy gamma ray sources, Barcelona, 04.07.06-07.07.06

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