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Neutrino Astronomy at the South Pole - Latest results from the AMANDA-II Neutrino Telescope

Neutrino, Astronomy, AMANDA-II, South Pole

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Neutrino Astronomy at the South Pole - Latest results from the AMANDA-II Neutrino Telescope

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  1. Neutrino Astronomy at the South PoleLatest results from the AMANDA-II Neutrino TelescopePaolo Desiati on behalf of the IceCube Collaborationdesiati@icecube.wisc.eduUniversity of Wisconsin – Madison from Quark n.36, 02/01/04 http://icecube.wisc.edu Particles and Nuclei International Conference (PANIC05) Santa Fe, NM (U.S.A.) October 24th, 2005

  2. Who is in IceCube ? Bartol Research Inst, Univ of Delaware, USA Pennsylvania State University, USA University of Wisconsin-Madison, USA University of Wisconsin-River Falls, USA LBNL, Berkeley, USA UC Berkeley, USA UC Irvine, USA Univ. of Alabama, USA Clark-Atlanta University, USA Univ. of Maryland, USA University of Kansas, USA Southern Univ. and A&M College, Baton Rouge, LA, USA Institute for Advanced Study, Princeton, NJ, USA Chiba University, Japan University of Canterbury, Christchurch, New Zealand Université Libre de Bruxelles, Belgium Vrije Universiteit Brussel, Belgium Université de Mons-Hainaut, Belgium Universiteit Gent, Belgium Universität Mainz, Germany DESY Zeuthen, Germany Universität Wuppertal, Germany Universität Dortmund, Germany Humboldt Universität, Germany Uppsala Universitet, Sweden Stockholm Universitet, Sweden Kalmar Universitet, Sweden Imperial College, London, UK University of Oxford, UK Utrecht University, Netherland Amundsen-Scott Station, Antarctica

  3. Amundsen-Scott South Pole Station Where are we ? Runway South Pole AMANDA-II

  4. “Up-going” (from Northern sky) “Down-going” (from Southern sky) AMANDA-II 19 strings 677 OMs Trigger rate: 80 Hz Data years: >=2000 AMANDA-B10 (inner core of AMANDA-II) 10 strings 302 OMs Data years: 1997-99 Optical Module PMT looking downward PMT noise: ~1 kHz

  5. O(km) long mtracks Event detection in the ice a neutrino telescope Qmn0.65o(En/TeV)-0.48 (3TeV<En<100TeV) event reconstruction by Cherenkov light timing O(10m) cascades ~17 m Nucl. Inst. Meth. A 524, 169 (2004)

  6. Array AMANDA IceCube ν astronomy : physics goals Bottom-Up scenario cosmic accelerator p + (p or )   + X  e ,+ X Flux  Eν-2(fermi acceleration)

  7. (statistical errors) Preliminary ν astronomy : backgrounds • intense muon flux from CR  - background for CR neutrinos • νμfluxes from CR  - background for ET neutrinos • conventional, prompt • ET neutrinos as excess of measured neutrino flux at high energies ( E-2)

  8. signal bin background estimation AMANDA-B10 average flux upper limit [cm-2s-1] AMANDA-II sin(d) n telescope : point source search  signal hypothesis  E-2 AMANDA-II - 2000-02 (607 days) 1 m2   Neutrino Effective Area 1997 : ApJ 583, 1040  (2003) 2000 : PRL 92, 071102 (2004) 2000-02 : PRD 71 077102 (2005) IceCube : Astrop Phys 20, 507 (2004) Average upper limit = sensitivity (δ>0°) (integrated above 10 GeV, E-2 signal)

  9. Maximum significance 3.4 s compatible with atmospheric n ~92% n telescope : point source search Preliminary • Search for clustering in northern hemisphere • compare significance of local fluctuation to • atmospheric n expectations • un-binned statistical analysis • no significant excess 2000-2003 (807 days) 3329 n from northern hemisphere 3438 n expected from atmosphere

  10. n telescope : unresolved sources ? neutrinos from single steady sources may be as many as background stacking source analysis (2000) time-correlation with transient phenomena (2000-03) known active flary periods of TeV gamma sources if neutrinos in coincidence with gamma emission limit / source single point source sensitivity (4yrs) • search neutrinos in time-space coincidence with GRB • νμand all-flavor searches with Waxman-Bahcall spectrum • all-flavor rolling-time search with WB spectrum • 1 and 100 s time windows • GRB030329 case with specific spectrum based on observed electromagnetic parameters (Band fit, red shift): astro-ph/0510336 • SGR 1806-20 (Dec 27th 2004): astro-ph/0503348 • muons from gamma interaction in atmosphere • no signal detected therefore limits assigned time-rolling search over 2000-03 period optimized angular search bin : 2.25°-3.75°

  11. n telescope : diffused sources HE νμ - tracks: 2π coverage HE νe+νμ+ντ- cascades: 4π coverage Astroparticle Physics 22 (2004) 127 Preliminary • atm νμ unfolded spectrum : limit (2000, 197d) • ΦνE2 < 2.6 × 10-7 GeV cm-2s-1sr-1 • (100 TeV < E < 300 TeV) • energy estimator = # hit OM : sensitivity (2000-03, 807d) • ΦνE2 < 9.5 × 10-8 GeV cm-2s-1sr-1 (no syst)PRELIMINARY • (13 TeV < E < 3.2 PeV) • HE cascades : limit (2000, 174d) • ΦνE2 < 8.6 × 10-7 GeV cm-2s-1sr-1 • (50 TeV < E < 5 PeV)

  12. n telescope : diffused sources UHE νe+νμ+ντ:4π coverage • Earth opaque to PeV neutrinos→ look up and close to horizon • Look for very bright events (large number of multiple hits / sensor) • Train neural network to distinguish E-2 signal from background Astroparticle Physics 22 (2005) 339 simulated UHE event in AMANDA-B10 • UHE cascades : limit (1997, 131d) • ΦνE2 < 9.9 × 10-7 GeV cm-2s-1sr-1 • (1 PeV < E < 3 EeV) • UHE cascades : limit (2000, 174d) • ΦνE2 < 3.5 × 10-7 GeV cm-2s-1sr-1 • (0.2 PeV < E < 2 EeV)

  13. n telescope : all-flavor summary • limits on E-2 • would need to model • other spectra • oscillations accounted • @ Earth • all-flavor limits / 3 νe (cascades B10 1yr) all-flavor limits νμ (B10 1yr) νe+νμ+ντ (UHE B10 1yr) νμ (A-II 1yr) νe+νμ+ντ(cascades A-II 1yr) νμ (A-II 4yr) νe+νμ+ντ (UHE A-II 1yr) sensitivity limit

  14. No Extraterrestrial neutrino signal observed yet ! • AMANDA-II upper limits getting tighter and constraining models • ice properties well understood • improving background rejection capabilities • still improving reconstruction event quality • toward clean atmospheric νμmeasurement as background • improve strategies for sensitivity enhancement • AMANDA will overlap the lower energy tail of IceCube sensitivity “The n“ @ South Pole

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