Imaging the Neutrino Universe with AMANDA and IceCube David Hardtke University of California, Berkeley Motivations for neutrino astronomy Selected AMANDA results IceCube: Status and Plans Lake Louise Winter Institute February 2005

Neutrino Astronomy

Neutrino Production and Detection Candidate astrophysical accelerators for high energy cosmic rays: Active Galactic Nuclei Gamma-Ray Bursts Neutrino production at source: p+ or p+p collisions Neutrino astronomy requires large detectors Low extra-terrestrial neutrino fluxes Small cross-sections dN/dEE-2 dN/dEE-3.7

Amundsen-Scott South Pole station Dome road to work AMANDA Summer camp 1500 m Amundsen-Scott South Pole station 2000 m [not to scale]

Neutrino Detection in Polar Ice event reconstruction by Cherenkov light timing South Pole ice: O(km) long muon tracks ~15 m cascades Km tracks at TeV, cm at MeV Longer absorption length  larger effective volume

Atmospheric Neutrinos PRELIMINARY Muon Neutrino Flux Maximum E-2 contribution AMANDA test beam(s): atmospheric  (and ): Neural Net Energy Reconstruction (upgoing ) “Unfold” to get neutrino Energy Spectrum Limit on diffuse E-2 flux (100-300 TeV): E2 (E) < 2.6·10–7 GeV cm-2 s-1 sr-1

Diffuse Extra-terrestrial Neutrino Search Astroparticle Physics 22, 127 (2004) “Cascade” search: 4  coverage Signal Background After optimized cuts: Nobs = 1 event Natm  = 0.90 Natm  = 0.06 ± 25%norm +0.69 -0.43 +0.09 -0.04

Diffuse PeV-EeV neutrino search m tracks Earth opaque to PeV neutrinos  look horizontally Look for superbright events (large number of Optical Modules with hits) Train neural network on dN/dE  E-2 signal Simulated UHE event Nobserved = 5 Nbackground = 4.6  1.2 Astroparticle Physics 22, 339 (2005)

Summary of Diffuse Flux Limits All-flavor Flux Limits vs. Model Predictions Cascades Unfolded Atmospheric (x3) Horizontal UHE Models Excluded: S91 (Stecker et al) AGN Core S96 (Stecker et al) AGN Core (updated) P97 (Protheroe) AGN Jet Barely Alive: M 95 (Mannheim) AGN Jet

Neutrino Point Source Search Four Year (2000-2003) analysis Optimize cuts in each declination band assuming E-2 spectrum 3369 upgoing  events < 5% fake events

“Hot spot” search Significance Map: Largest excess is 3.35  Assess statistical significance using random skymaps. No statistically significant hot spots !

Round Up the Usual Suspects Search for high energy neutrino excess from known gamma emitting sources: Usual suspect z Luminosity distance Nobserved Nback 1ES 1959+650 0.047 219 Mpc 5 3.71 Markarian 421 0.03 140 Mpc 6 5.58 QSO 1633+382 1.8 14000 Mpc 4 QSO 0219+428 0.44 2600 Mpc 4.31 CRAB 1.9 kpc 10 5.36 TeV Blazars GeV Blazars Supernova Remnant No Statistically Significant Excess from 33 Targeted Objects

IceCube 80 strings with 60 optical modules (OMs) on each Effective Volume ≈ 1 km3 Size required to see “guaranteed” neutrino sources Surface Array (IceTop) PMT signal digitization in ice.

IceCube Sensitivity

January 2005: First String Deployed! IceCube Status January 2005: First String Deployed!

Conclusions No Extra-terrestrial neutrino signal observed Diffuse flux searches (TeV - EeV) Point source searches No statistically significant hotspots No evidence for high-energy neutrino emission from gamma emitting objects IceCube under construction 2-3 order of magnitude improvement in sensitivity

IceCube Simulated Events Eµ=10 TeV e  e E = 375 TeV ~300m for PeV t

How large is IceCube? AMANDAII 300 m Super K 1500 m 50 m 2500 m