Results from the AMANDA Neutrino Telescope

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Results from the AMANDA Neutrino Telescope. CRIS06, Catania, June 2006 Juande D. Zornoza University of Madison-Wisconsin. Neutrino CV. Neutral Stable Weakly interacting*. Neutrino Astronomy. High energy astronomy: Which probes can we use?. Photon and proton mean free range path. - PowerPoint PPT Presentation

Text of Results from the AMANDA Neutrino Telescope

  • Results from the AMANDA Neutrino TelescopeCRIS06, Catania, June 2006

    Juande D. ZornozaUniversity of Madison-Wisconsin

  • Neutrino Astronomy Photons interact with the CMB and with matter Cosmic rays are deflected by magnetic fields and also interact with matter Neutrons are not stableHigh energy astronomy: Which probes can we use?What else? Oh, yeah, neutrinos!Photon and proton mean free range path*very large detectors needed

  • Production MechanismsGamma and cosmic ray astrophysics are deeply related with neutrino astronomy:Neutrino flavor rate: e:: ~ 1:2:
  • Scientific Scopes?Other physics: monopoles, Lorentz invariance, super-massive DM , SUSY Q-balls, etc...


    Average increase in the PMT counting rate

    TeV-PeVAstrophysical sources (AGNs, GRBs, MQs)

    Up-going muons and cascades

    PeV-EeVAGNs, TD, GZK neutrinosAlmost horizontal tracks

    EeV?Down-going tracks


    GeV-TeVNeutralino searchUp-going muons

  • AMANDA/IceCube CollaborationUSA (12)Europe (13)JapanNew Zealand Bartol Research Institute, Delaware, USA Pennsylvania State University, USA UC Berkeley, USA UC Irvine, USAClark-Atlanta University, USA Univ. of Maryland, USA IAS, Princeton, USA University of Wisconsin-Madison, USA University of Wisconsin-River Falls, USA LBNL, Berkeley, USA University of Kansas, USA Southern University and A&M College, Baton Rouge, USA Universite Libre de Bruxelles, Belgium Vrije Universiteit Brussel, Belgium Universit de Gent, Belgium Universit de Mons-Hainaut, Belgium Universitt Mainz, Germany DESY-Zeuthen, Germany Universitt Dortmund, Germany Universitt Wuppertal, Germany Uppsala university, Sweden Stockholm university, Sweden Imperial College, London, UK Oxford university, UK Utrecht,university, Netherlands Chiba university, Japan University of Canterbury, Christchurch, NZ

  • South PoleRunwayAMANDA-IIAmundsen-Scott South Pole Station

  • AMANDA Detector1997-99: AMANDA-B10 (inner lines of AMANDA-II)10 strings302 PMTsfrom 2000: AMANDA-II19 strings677 OMs20-40 PMTs / stringAt the surface: SPASECoincident eventsAngular resolution Cosmic ray composition

    SPASEtrigger rate = 80 Hz

  • SignaturesCC- interactions:long (~km) tracksNC- and CC-e/ interactions:cascades(tracks short w.r.t. the inter-OM distance)15 m Other signatures, like double bang, are expected to be more rare.

  • BackgroundThere are two kinds of background:-Muons produced by cosmic rays in the atmosphere ( detector deep in the ice and selection of up-going events).-Atmospheric neutrinos (cut in the energy, angular bin).

  • Ice PropertiesShorter scattering length than in sea, but longer absorption length (larger effective volume):bubblesdust Absorption dusticeAverage optical ice parameters:

    labs ~ 110 m @ 400 nmlsca ~ 20 m @ 400 nmScattering Moreover, very silent medium: dark noise < 1.5 kHz

  • Event reconstructionThe position, time and amplitude registered by the PMTs allows the reconstruction of the track, using Likelihood optimization techniques.The angular resolution depends on the quality cuts of each specific analysis. For instance, in the point-like source search, it is 2.25-3.75 deg (declination dependent).Once reconstructed the positions of the tracks, we can compare the number of events in each signal bin with the background at that declination.example of AMANDA event

  • Sky mapThe largest fluctuation (3.4) is compatible with atmospheric background2000-2003 (807 days)3329 ns detected from Northern Hemisphere3438 atmospheric ns expected

  • PerformanceNeutrino Effective AreaSensitivity to E-2 Point-like sources Sensitivity: Average upper limit, integrated above 10 GeV. Steady increase with time.For E10 PeV the Earth becomes opaque to neutrinos.Ndet=Aeff Time Flux

  • AGNs: Stacking source analysissingle source sensitivity(four years) Neutrino astronomy could be the key for establishing the hadronic/leptonic origin of the HE photons from AGNs.

    Stacking-source analysis: The flux from AGNs of the same type integrated to enhance the statistics.preliminary No significant excess has been found. The stacking approach improves the one source limit by a factor three, typically.

  • Multi-wavelength approachTransient events also provide an opportunity to enhance sensitivityWe can look for correlations with active periods from electromagnetic observations:Blazars: X-raysMicroquasars: radio

    2000-03 datasources: TeV blazars, microquasars and variable sources from EGRET

    SourcePeriod wtih high activity#events in high state Expected background in high stateMarkarian 421141 days01.631ES1959+650283 days21.59Cygnus X-3 114 days21.37

  • Transient sourcesWhen the variable character of the source is evident, but the EM observations are limited, we can use the sliding-window technique.For the time-rolling source search, events in a sliding time window are searched:Galactic: 20 daysExtragalactic: 40 dayssources: TeV blazars, microquasars and variable sources from EGRETGalacticExtragalactic

    Source#events(4 years)Expected background(4 years)Period durationMarkarian 42165.5840 d1ES1959+65053.7140 d3EG J1227+430264.3740 dQSO 0235+16465.0440 dCygnus X-365.0420 dGRS 1915+10564.7620 dGRO J0422+3255.1220 d

  • Orphan FlareThree events in 66 days within the period of a mayor 1ES 1959+650 burst (orphan flare:s but no X-rays)A posteriori search undefined probability of random coincidence.sliding search window

  • Diffuse fluxesAtmospheric neutrino spectrum is reconstructed using regularization-unfolding techniques. No extraterrestrial diffuse component has been observed.E2 d/dE = 1.1 x 10-7 GeV cm-2 s-1 sr-1 (over the range 16 TeV to 2 PeV)

  • UHE neutrinos (I)UHE neutrinos (>106 GeV) can be produced in several scenarios (AGNs, topological defects, GZK)>107 GeV the Earth is opaque to neutrinos search for horizontal tracks.Background: muon bundles from atmospheric showers.Neural network trained to distinguish between signal and backgroundsimulated UHE event

  • UHE neutrinos (II)Signal versus background:Signal produces higher light densityThere are more hits in UHE single muons, due to the after-pulsing in the photomultipliers.Background events are produced mainly vertically down-wards and signal events are expected to be horizontal.Different residual time distributions (because of after-pulsing)Center of gravity of hits pulled away from the geometrical center of the detector for down-going bundles.

  • UHE neutrinos (III)2000 data used for this analysis:20% for the optimization of cuts80% after unblinding is approvedThere is a factor two of improvement in the sensitivity w.r.t. AMANDA B10Limit = 3.710-7 GeV cm-2 s-1 sr-1 (from 1.8105 to 1.8109 GeV)

  • UHE neutrinos (IV)PRELIMINARY sensitivities to different models of UHE production:

    L. Gerhardt

    SourceNumber expected in 80% of 1 year (138.8 days) all MRF for 80% sample (FC = 3.49)AGN core (Stecker et al 96)37.00.09AGN core (Stecker et al 92)8.90.39AGN jet (Protheroe 96)8.90.40AGN jet (Halzen and Zas 97)8.50.41Z-Burst (Kalashev et al 02)3.60.96Mono-Energetic p- (Semikoz 03)0.655.4Topological Defect (Sigl et al 98)0.635.5E-2 p- (Semikoz 03)0.457.8Z-Burst (Yoshida et al 98)0.1524.0p- (Engel et al 01)0.012298.8

  • SGR 1806-20We try to observe down-going muons produced by TeV photons discriminating the background of atmospheric muons using an angular and a time windowRA (J2000) 18h 08m 39.4s = 272.16 degDEC (J2000) -20deg24'39.7" = -20.41 degDuration < 0.6 sTime window 1.5 sThe SGR 1806-20 flare (Dec. 2004) was more than one order of magnitude more powerful (2x1046 erg) than previous flares: detectors saturated.+Swift-BAT light curve

    SatelliteTrigger time at Earth (ms)GEOTAIL21:30:26.71INTEGRAL21:30:26.88RHESSI21:30:26.64CLUSTER 421:30:26.15Double Star21:30:26.49

  • SGR 1806-20MDF have jumps when we have to increase the (discrete) number of events needed to satisfy the condition of 5 confidence interval.MRF behaves smoothly since only the mean expected background in taken into account.5 events, time window: 1.5 s Confidence interval=5Statistical Power=90% DiscoveryOptimum cone size: 5.8Best MDF: 2.3Observed events needed: 4Background: 0.06

  • SGR 1806-20Unfortunately, no event was found after unblinding, so upper limits have been calculated.

    neutrinosgammas Limits in the constant of a d/dE=A E-1.47 flux are set, constraining both the HE gamma and neutrino emission.preliminaryEffective areasLimit in flux normalization

  • GRBs (average spectrum)Search time window: from 10 sec before the burst start to the end of the burst.Precursor: from -110 sec to -10 sec.Background estimation: from 1 hour before to 1 hour after (except 10 minutes around the burst which remain unblinded)

    years# GRBsselection criterionlimit (GeV cm-2 sr-1)97-00312BATSE410-800-03139BATSE + IPN310-800-03 (with precursor)50510-80074BATSE9.510-7

  • Neutralino SearchWIMPs would scatter elastically in the Sun or Earth and become gravitationally trapped.They would annihilate producing standard model particles.Among the annihilation products, only neutrinos can reach us.Neutralinos annihilate in pair-wise mode:ann: annihilation rate per unit of volumeann: neutralino-neutralino cross-sectionv: relative speed of the annihilating particles: neutralino mass densitym: neutralino massand neutrinos are produced as secondaries.

  • Neutralino Searchexcluded by EdelweissThe Sun is the most promising source of neutralinos.Neutralino density in the Earth is diminished the effect of the Sun mass.

  • ConclusionsAMANDA has been operating for almost one decade.No extraterrestrial neutrino has