Hermann Kolanoski Humboldt-Universität zu Berlin and DESY Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 1
What I want to tell you: What want to you – Cosmic rays (CR) Cosmic rays (CR) – How to measure cosmic rays measure cosmic rays – What we know and don‘t know about CR know and don‘t know about CR – Neutrinos as messengers of cosmic accelerators – Neutrino Observatory IceCube – The IceCube Muppet Show .... – Do not talk about e.g. exotic searches (wimps, …) Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 2
Cosmic Rays Cosmic 100 years after their discovery not yet understood 100 years after their discovery not yet understood ion pairs / (cm 3 s) faster discharge of an electrometer with increasing height Viktor Hess 1912 5 km height interpreted due to radiation Kernfragmente from space: “Höhenstrahlung” Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 3
Zwicky’s proposal for the CR Origin In Los Angeles Times, Jan. 1934 “Cosmic rays are caused by exploding stars which burn with a fire equal to 100 million suns and then shrivel from ½ million mile diameters to little spheres 14 miles thick.”, says Fritz Zwicky, Swiss Physicist. … since then we are trying to prove it Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 4
Cosmic Ray Spectrum ~ 32 decades ⇒ very different detection methods ~E -2.7 very different ~ 32 decades detector sizes LHC(pp) LHC(p) cut-off? Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 5
Cosmic Ray Spectrum ~ 32 decades ⇒ very different detection methods ~E -2.7 very different ~ 32 decades detector sizes LHC(pp) LHC(p) Where and how are the highest energies produced??? What is the elemental composition? Galactic and/or extragalactic? cut-off? Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 6
Extensive Air Showers Use the atmosphere as calorimeter Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 7
Air Shower Detectors distance 125 m IceTop size 1 km 2 IceTop energies PeV – EeV 1 km 2 Pierre Auger Observatory distance 1500 m size 3000 km 2 energies EeV – 100 EeV 3000 km 2 Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 8
PeV to EeV The fine structure in the spectrum M.G. Aartsen et al, Physical Review D88 (2013) 042004! 𝛿 =2.65 3.14 2.90 𝐺 = 𝐹 −𝛿 3.37 Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 9
Confinement in the Galaxy p = = ρ Rigidity : R B z e H O Fe 10 kpc E max ~ Z ⇒ E max (Fe) ≈ 26 E max (H) CR in galaxy: mean lifetime 10 7 years Energy has to be refueled. Where, how? Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 10
Origin and Physics of the knee(s) If the knee is due to the diffusion out of p knee the galaxy we expect a change in Fe knee composition towards heavier elements spectrum below the knee: well known by direct measurements; above the knee: indirect measurements via air showers, difficult Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 11
Cosmic Ray Anisotropy 5 TeV IceCube 17 TeV The orientation of the dipole moment does not correspond to the relative motion (~200 km/s) in the Galaxy (Compton-Getting effect) Diffusive transport in galactic magnetic field from nearby sources? Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 12
Energy Dependence of CR Anisotropy Energy Dependence of CR Anisotropy Energy Dependence of CR Anisotropy 17 TeV 590 TeV 41 TeV 1.2 PeV 75 TeV 4.5 PeV 140 TeV • Anisotropy changes in position, size 240 TeV • Above 400 TeV there’s indication of an increase in strength. Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 13
Large and Small Scale Anisotropies diffusive transport from nearby sources? observed small scale (10°) structures ⇒ few pc distance Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 14
UHECR Results Auger Observatory Cen A direction correlation with AGN? cut-off at 10 20 eV definitely observed 28/84 = 33% GZK or source power limited? isotropic background = 21% (GZK = Greisen-Zatsepin-Kuzmin) ➙ <1 % chance probability Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 15
Cosmic Rays, CMB Photons and Neutrinos Cosmic Microwave Background (CMB): perfect blackbody at 2.74 K CMB 2.7 K → threshold E p ≈ 4 ×10 19 eV “GZK horizon” ~160 Mly Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 16
Nature of the Cutoff? Is this the “GZK cutoff”? Energy loss by collison with CMB photons? Or do accelerators run out of steam? ⇒ composition becomes heavier Fe Auger: X max with florescence detectors data suggest change of composition from light to heavy Not GZK cutoff? Clarification from other messengers? Are there GZK neutrinos? Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 17
Where could particles possibly be accelerated? Hillas diagram B E max ≈ 10 18 eV z β s (L / kpc) (B / μ G) supernova L remnants (SNR) gamma ray bursts (GRB) active galactic nuclei (AGN) black holes Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 18
Cosmic Accelerators Fermi acceleration at shock front Supernova Remnants (SNR) 1 % of the energy of all SN explosions can explain energy density of cosmic rays in galaxy (~ 0.5 MeV/m 3 ) However: No SNR has been Crab Nebula (explosion 1054) clearly pinned down as source Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 19
Twisted and Straight Paths Charged Particle Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 20
Absorption of γ ‘s by γ γ -> e + e - γ e + γ e - σ γγ 1 ~ s 2 m e s I know! I did γ γ → hadrons Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 21
Cosmic Rays, Gammas and Neutrinos CR – ν connection ν π ± accelerator p ν μ ± ν the γ – ν connection π 0 for hadron accelerators γ target target γ ν spectrum ~ E -2 assumed CR – γ connection Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 22
Neutrino fluxes Cosmic neutrinos should have a hard spectrum F ~ E -2 E -3.7 atmospheric ν F ~ E -3.7 E -2 Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 23
How to detect cosmic high energy neutrinos? quite difficult Absorption small detection probability small ⇒ large target volume Mediterranean Sea Most efficient: Cherenkov light from charged ν products Lake Baikal ⇒ transparent ⇒ water or ice Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 24
Amundsen – Scott Station Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 25
Approaching the Pole these Days Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 26
Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 27
Arriving at Pole Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 28
IceCube Neutrino Observatory air shower array IceTop neutrino telescope • 86 Strings, 2450 m deep • 5160 Optical Modules IceCube 1000 m • Instrumented: 1 km 3 DeepCore • IceTop: 1 km 2 • Installation: 2005-2011 29 Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory
The Drill Camp Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 30
…. 2450 m deep Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 31
.. what you see down there Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 32
When the Season is over Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 33
The Last Flight at the End of the Season Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 34
Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 35
Detection of High Energy Neutrinos atmosph. Muons mean free path 1 lightyear ν µ +N → µ + X 10 12 10 10 µ km Radius 10 8 density of Universe 10 -23 × ρ (H 2 O) Earth orbit 10 6 atmosph. 10 4 ν µ Neutrinos Earth diameter 10 2 extraterr. MeV GeV TeV PeV EeV ZeV Neutrinos Energy even for neutrinos the Earth becomes opaque above about 1 PeV Earth as filter ⇒ look upward – atm. background becomes less Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 36
Detecting a Neutrino Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 37
Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 38
Particle Signatures up-going ν µ ν l l ± X X → point sources Z 0 W ± N N ν l ν l CR shower CC NC in IceTop - muon tracks µ - em + had. shower µ ν µ µ bundle background ν e cascade & → all flavours physics ν e Coll. Ljubljana, 16. 3. 2015 H.Kolanoski - IceCube Neutrino Observatory 39
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