Results from the AMANDA Neutrino Telescope CRIS 06

Results from the AMANDA Neutrino Telescope CRIS 06, Catania, June 2006 Juande D. Zornoza University of Madison-Wisconsin

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

Production Mechanisms o Gamma and cosmic ray astrophysics are deeply related with neutrino astronomy: Cosmic rays Gamma ray astronomy Neutrino flavor rate: : ~ 1: 2: <10 -5 at the source e: : ~ 1: 1: 1 at the detector

Scientific Scopes ? Energy Physics Signature ~Me. V Supernovae Average increase in the PMT counting rate Ge. V-Te. V-Pe. V-Ee. V ØEe. V Neutralino search Astrophysical sources (AGNs, GRBs, MQs) AGNs, TD, GZK neutrinos ? Almost horizontal tracks Down-going tracks Up-going muons and cascades Other physics: monopoles, Lorentz invariance, super-massive DM , SUSY Q-balls, etc. . .

AMANDA/Ice. Cube Collaboration • Bartol Research Institute, Delaware, USA • Pennsylvania State University, USA • UC Berkeley, USA • UC Irvine, USA • Clark-Atlanta University, USA • Univ. of Maryland, USA (12) • 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 Japan Europe (13) • Chiba university, Japan • University of Canterbury, Christchurch, NZ New Zealand • Universite Libre de Bruxelles, Belgium • Vrije Universiteit Brussel, Belgium • Université de Gent, Belgium • Université de Mons-Hainaut, Belgium • Universität Mainz, Germany • DESY-Zeuthen, Germany • Universität Dortmund, Germany • Universität Wuppertal, Germany • Uppsala university, Sweden • Stockholm university, Sweden • Imperial College, London, UK • Oxford university, UK • Utrecht, university, Netherlands

Amundsen-Scott South Pole Station Runway South Pole AMANDA-II

AMANDA Detector o 1997 -99: AMANDA-B 10 (inner lines of AMANDA-II) n n o 10 strings 302 PMTs from 2000: AMANDA-II n n n 19 strings 677 OMs 20 -40 PMTs / string SPASE At the surface: SPASE § Coincident events § Angular resolution § Cosmic ray composition 1 km 2 km trigger rate = 80 Hz

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

Background • There 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…). p

Ice Properties o Shorter scattering length than in sea, but longer absorption length (larger effective volume): Average optical ice parameters: labs ~ 110 m @ 400 nm lsca ~ 20 m @ 400 nm Absorption Scattering ice bubbles dust Moreover, very “silent” medium: dark noise < 1. 5 k. Hz

Event reconstruction o o o The 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. signal bin background estimation example of AMANDA event

Sky map 2000 -2003 (807 days) 3329 s detected from Northern Hemisphere 3438 atmospheric s expected ~92% The largest fluctuation (3. 4 ) is compatible with atmospheric background

Performance Sensitivity to E-2 Point-like sources average flux upper limit [cm-2 s-1] Neutrino Effective Area AMANDA-B 10 AMANDA-II Ndet=Aeff × Time × Flux sin(d) • For E <10 Pe. V, Aeff grows with energy due to the increase of the interaction cross section and the muon range. • For E >10 Pe. V the Earth becomes opaque to neutrinos. • Sensitivity: Average upper limit, integrated above 10 Ge. V. • Steady increase with time.

AGNs: Stacking source analysis q Neutrino astronomy could be the key for establishing the hadronic/leptonic origin of the HE photons from AGNs. pre lim ina ry q Stacking-source analysis: The flux from AGNs of the same type integrated to enhance the statistics. single source sensitivity (four years) q No significant excess has been found. q. The stacking approach improves the one source limit by a factor three, typically.

Multi-wavelength approach o o Transient events also provide an opportunity to enhance sensitivity We can look for correlations with active periods from electromagnetic observations: n n Blazars: X-rays Microquasars: radio Period wtih high activity #events in high state Expected background in high state Markarian 421 141 days 0 1. 63 1 ES 1959+650 283 days 2 1. 59 Cygnus X-3 114 days 2 1. 37 Source sources: Te. V blazars, microquasars and variable sources from EGRET 2000 -03 data

Transient sources o o When 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: n n Galactic: 20 days Extragalactic: 40 days Galactic Extragalactic Source #events (4 years) Expected background (4 years) Period duration Markarian 421 6 5. 58 40 d 1 ES 1959+650 5 3. 71 40 d 3 EG J 1227+4302 6 4. 37 40 d QSO 0235+164 6 5. 04 40 d Cygnus X-3 6 5. 04 20 d GRS 1915+105 6 4. 76 20 d GRO J 0422+32 5 5. 12 20 d sources: Te. V blazars, microquasars and variable sources from EGRET

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

Diffuse fluxes o. Atmospheric neutrino spectrum is reconstructed using regularization-unfolding techniques. o. No extraterrestrial diffuse component has been observed. E 2 d /d. E = 1. 1 x 10 -7 Ge. V cm-2 s-1 sr-1 (over the range 16 Te. V to 2 Pe. V)

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

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

UHE neutrinos (III) o 2000 data used for this analysis: n n o 20% for the optimization of cuts 80% after unblinding is approved There is a factor two of improvement in the sensitivity w. r. t. AMANDA B 10 Limit = 3. 7 10 -7 Ge. V cm-2 s-1 sr-1 (from 1. 8 105 to 1. 8 109 Ge. V)

UHE neutrinos (IV) o PRELIMINARY sensitivities to different models of UHE production: Number expected in 80% of 1 year (138. 8 days) all MRF for 80% sample (FC = 3. 49) AGN core (Stecker et al 96) 37. 0 0. 09 AGN core (Stecker et al 92) 8. 9 0. 39 AGN jet (Protheroe 96) 8. 9 0. 40 AGN jet (Halzen and Zas 97) 8. 5 0. 41 Z-Burst (Kalashev et al 02) 3. 6 0. 96 Mono-Energetic p-γ (Semikoz 03) 0. 65 5. 4 Topological Defect (Sigl et al 98) 0. 63 5. 5 E-2 p-γ (Semikoz 03) 0. 45 7. 8 Z-Burst (Yoshida et al 98) 0. 15 24. 0 p-γ (Engel et al 01) 0. 012 298. 8 Source L. Gerhardt

SGR 1806 -20 The SGR 1806 -20 flare (Dec. 2004) was more than one order of magnitude more powerful (2 x 1046 erg) than previous flares: detectors saturated. RA (J 2000) 18 h 08 m 39. 4 s = 272. 16 deg DEC (J 2000) -20 deg 24'39. 7" = -20. 41 deg Duration < 0. 6 s Satellite 0. 4 s + Trigger time at Earth (ms) GEOTAIL 21: 30: 26. 71 INTEGRAL 21: 30: 26. 88 RHESSI 21: 30: 26. 64 CLUSTER 4 21: 30: 26. 15 Double Star 21: 30: 26. 49 Time window 1. 5 s Swift-BAT light curve We try to observe down-going muons produced by Te. V photons discriminating the background of atmospheric muons using an angular and a time window

SGR 1806 -20 5 events, time window: 1. 5 s Confidence interval=5 Statistical Power=90% o o Discovery n Optimum cone size: 5. 8° n Best MDF: 2. 3 n Observed events needed: 4 n Background: 0. 06 MDF 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.

SGR 1806 -20 o Unfortunately, no event was found after unblinding, so upper limits have been calculated. Effective areas Limit in flux normalization pr eli neutrinos gammas • Limits in the constant of a d /d. E=A E-1. 47 flux are set, constraining both the HE gamma and neutrino emission. mi na ry

GRBs (average spectrum) o o o 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 # GRBs 97 -00 312 00 -03 139 00 -03 (with precursor) 50 00 74 selection criterion limit (Ge. V cm-2 sr-1) BATSE + IPN BATSE 4 10 -8 3 10 -8 5 10 -8 9. 5 10 -7

Neutralino Search o o WIMPs 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: and neutrinos are produced as secondaries. ann: annihilation rate per unit of volume ann: neutralino-neutralino cross-section v: relative speed of the annihilating particles : neutralino mass density m: neutralino mass

Neutralino Search excluded by Edelweiss The Sun is the most promising source of neutralinos. Neutralino density in the Earth is diminished the effect of the Sun mass.

Conclusions o o AMANDA has been operating for almost one decade. No extraterrestrial neutrino has been observed above the atmospheric background, YET… Increasingly stringent limits have been set in but sometimes point-like sources, diffuse fluxes, neutralinos… success comes after much work A bigger detector is needed Ice. Cube and patience! (already in construction!) Thanks to the organizers!

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Particle Physics

Monopoles o o Monopoles would also give a large signal in the detector, which can be discriminated from high energy muons. Two signatures are possible: n. Direct emission (βm>0. 74): × 8500 wrt muon n. Induced δ-ray emission (βm>0. 51)

GRB model parameterization b a b-2

GRBs (individual spectrum) o o The individual spectrum can be used instead of the average to enhance the sensitivity for a given burst. The parameters of the Band function of the GRB 030329 burst were calculated. Model neutrino energy flux (Ge. V cm-2 s-1) 1 2 3 Sensitivity Limit (Ge. V s-1 cm-2) isotropic (1) 0. 157 0. 150 beamed (2) 0. 041 0. 039 average (WB) (3) 0. 036 0. 035

GRBs: individual bursts

AGN models o o Low energy (from radio up to UV / Xray): non-coherent synchrotron radiation. High energy (up to Te. V) under debate: leptonic versus hadronic models.