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Neutrino astronomy with the IceCube Observatory

Neutrino astronomy with the IceCube Observatory. Alexander Kappes for the IceCube Collaboration 23 rd European Cosmic-Ray Symposium Moscow, 7. July 2012. Outline. Introduction and IceCube performance Diffuse neutrino fluxes at medium and high energies

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Neutrino astronomy with the IceCube Observatory

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  1. Neutrino astronomy withthe IceCube Observatory Alexander Kappes for the IceCube Collaboration 23rd European Cosmic-Ray Symposium Moscow, 7. July 2012

  2. Outline • Introduction and IceCube performance • Diffuse neutrino fluxes at medium and high energies • Point-like sources and Gamma-Ray Bursts • Other physics covered by IceCube

  3. π± + X μ + νμ e + νμ + νe → p + p(γ): π0 + X γ + γ → e + γ(Inverse Compton): e → e + γ ν γ p Messengers of the high-energy universe source p ,e

  4. PMT amplitudes Energy muon cascade nuclearreaction νμ Neutrino detection principle • Transform natural abundance of transparent medium(ice, water) into a particle detector Time & position of hits μ (~ ν) trajectory

  5. muon (IceCube) cascade (IceCube) Neutrino signatures • Track-like: • Source: νμ CC interaction • Good angular resolution (< 1°) • Sensitive volume ≫ instrumented volume • Cascade-like: • Source: νe, νμ, ντNC + νe CC interaction • Good energy resolution (few 10%) • Bad angular resolution ( > O(10°) ) • Sensitive volume ≈ instrumented volume • Composites: • Source: ντCC & νμ CC inside instrumented volume • Challenging to reconstruct

  6. cosmic rays p μ νμ cosmic νμ μ νμ atmosphere p Atmospheric muons and neutrinos • Muons detected year-1 (IceCube) • atmospheric* μ 7×1010 • atmospheric** ν→μ 5×104 • astrophys (expct) ν→μ O(10) • * 2000 per second • ** 1 every 6 minutes

  7. Neutrino telescope projects Baikal ANTARES KM3NeT (preparation phase) Text IceCube

  8. -1450 m -2450 m The IceCube observatory • Completed since Dec. 2010 • IceTopAir shower detector • InIce86 strings (5160 PMTs)Instrumented volume: 1 km3 • Deep Coredensely instrumentedcentral region (8 strings) → see talk by H. Kolanoski

  9. Detector history and status • IC86 uptime typical 99% (only 2% failed DOMs) • Detector sensitivity increases faster than # strings

  10. Waxman&Bahcall bound astrophysical neutrinos Atmospheric neutrinos • High statistics sample~ 50.000 per year • Prompt componentstill unknown • Both signal andbackground (IC40)

  11. Cosmogenic neutrinos: p + CMB → n + π+ ↳ μ+ + νμ W&B bound Cosmic diffuse neutrino fluxes IC59 • Search for excess inhigh energy tail • Requires knowledge ofprompt component atm. ν cosmic ν (E-2)

  12. Aug. 9, 2011 Jan 3, 2012 Cosmogenic neutrinos (IC79+86-I) • Optimized cuts for UHE neutrinos: • Expected background = 0.14(without prompt) • Observed = 2 (p-value 2.3σ) preliminary IC86-I predictions # events within livetime prompt background(no prompt) log10 NPE (energy proxy)

  13. Sensitivity UHE neutrinos (IC79+86-I) • Closing in on predictions • No significant excess so far • Substantial improvements in analysis anticipated Stay tuned!

  14. Skymap events (IC40+59) preliminary • IceCube is an all-sky telescope • Main sensitivity to sources in the northern sky equatorial coordinates TeV − PeV Northern hemisphere 58,000 events atm. neutrinos atm. muons 87,000 events Southern hemisphere PeV − EeV 14

  15. 67% Point sources: Significance skymap (IC40+59) TeV − PeV preliminary atm. neutrinos atm. muons PeV − EeV 15

  16. Point sources: Selected sources (IC40+59) • 13 Galactic SNRs ... , 30 extragalactic AGNs • No significant excess (both all-sky and source list) up to now • Unblinding of IC79 data soon preliminary

  17. Point sources: Sensitivities & upper limits 90% CL sensitivity / upper limits for E-2 spectrum MACRO ANTARES IceCube KM3NeT discovery region Galactic Center Galactic γ-ray sources

  18. Fireball model 104 GRB030329 1000 internal shocks p + π0 E2 × flux [keV cm-2 s-1] 100 γ(PeV) collapse p n + π+ ν(PeV) 10 e γ(MeV) 1 10 100 Energy [keV] Gamma-ray bursts (GRBs) • Short, very intense flashes of γ radiation (keV-MeV) • Ejected material has Γ ≳ 300 • One of few candidate sources for UHECRs

  19. Off-time IC59: 98 bursts in northern sky background On-time (blind) Off-time prompt T0 model independent (several hours) precursor (~100 s) 1 TeV 100 TeV 10 PeV GRBs with IceCube • Using satellite information (time and direction, GCN)very low background → 1 event can be significant ! • Observed busts (northern sky) • IceCube 40: 117 • IceCube 59: 98 • Individual modeling of neutrino fluxes(fireball model) flux Waxman&Bahcall Sum of 98 bursts

  20. low Γ prediction high Γ Are GRBs the sources of UHECRs? ×3.7 90% UL E2 × flux [GeV cm-2 s-1 sr-1] allowed neutrino break energy [GeV] Nature Vol. 484, 351 (2012) GRBs: IceCube results (IC40+59) Expected = 8.4 Observed = 0

  21. Conclusions from GRB analyses • Where are the neutrinos? • GRBs not origin of UHECRs ? (according to some models) • Physics modeling not sufficient ?(models are being revisited → significant flux reductions) • Unblinding of IC86-I soon • Going near real-time with GRBs in future Waiting for neutrinos from GRBs !

  22. All-sky fluxes(e.g. cosmogenic) • Galactic plane • Extended structures(e.g. Fermi-Bubbles) • Point-like sources(SNRs, Binaries ...) • Transient sources (GRBs, AGN flares...) • Extended sources • Indirect DM search (Sun, Galactic halo) • Magnetic monopoles, Q-balls • Lorentz invariance violation • Spectrum around “knee” (1015−1017 eV) • Composition • Anisotropy • Galactic/LMC SNe • SN phases • Neutrino hierarchy • Charm in showers • Neutrino oscillations • K/π ratio in showers • Cross sections at very high energies Physics spectrum with IceCube Cosmic accelerators Diffuse fluxes Dark Matter & Exotic Physics Cosmic rays Supernovae Neutrino Properties &Particle Physics → see H. Kolanoski’s talk

  23. DeepCore low energy Θ=-90° νμ disappearance IceCube high energy IceCube high energy 100 GeV 12,000 km Θ=0° DeepCore low energy minimum 10 GeV systematics cos(90°-Θ) cos(90°-Θ) Θ=-90° Θ=0° Θ=-90° Θ=0° 1 GeV DeepCore -90° -45° 0° Dust layer DeepCore First steps into ν oscillations Top View • DeepCore: • Decreases energy threshold to ~10 GeV • Look for standard oscillations • Strategy: Simple cuts and reconstructions

  24. Summary and Outlook • IceCube detector completed since 1 1/2 years;provides unprecedented amount of high-quality data • IceCube is a multi-purpose observatory(neutrino astronomy, dark matter, SNe, cosmic-rays, particle physics ...) • Neutrino astronomy: • finally reaching sensitivity of astrophysical significance(GRBs, cosmogenic neutrinos, Waxman&Bahcall bound) • discovery of first cosmic neutrinos might be around the corner • Antarctic ice proves to be a good medium to study atmospheric neutrino oscillations→ low-energy extension (PINGU, few GeV threshold)→ study neutrino properties

  25. The IceCube collaboration

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