cc

Alexander Kappesfor the IceCube Collaboration

23rd European Cosmic-Ray SymposiumMoscow, 7. July 2012

Neutrino astronomy withthe IceCube Observatory

Alexander Kappes, ECRS’12, Moscow, 7. July 20122 cc

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

Alexander Kappes, ECRS’12, Moscow, 7. July 20123 cc

Messengers of the high-energy universe

p

π± + X μ + νμ

e + νμ + νe

→

γ

ν

p,e

p + p(γ):

π0 + X γ + γ

→

e + γ (Inverse Compton):

e + γ→

sourcee

Alexander Kappes, ECRS’12, Moscow, 7. July 20124 cc

Transform natural abundance of transparent medium(ice, water) into a particle detector

muon

νμ

nuclearreaction

cascade

Time & position of hitsμ (~ ν) trajectory

Energy

PMT amplitudes

Neutrino detection principle

Alexander Kappes, ECRS’12, Moscow, 7. July 20125 cc

Neutrino signatures

Track-like:

‣ Source: νμ CC interaction

‣ Good angular resolution (< 1°)

‣ Sensitive volume ≫ instrumented volume

Cascade-like:

‣ Source: νe, νμ, ντ NC + νe CC interaction

‣ Good energy resolution (few 10%)

‣ Bad angular resolution ( > O(10°) )

‣ Sensitive volume ≈ instrumented volume

Composites:

‣ Source: ντ CC & νμ CC inside instrumented volume

‣ Challenging to reconstruct

muon (IceCube)

cascade (IceCube)

Alexander Kappes, ECRS’12, Moscow, 7. July 20126 cc

Atmospheric muons and neutrinos

p

atmosphere

cosmicrays

μνμ

νμ

cosmic

p

μνμ

Muons detected year-1 (IceCube)

‣atmospheric* μ7×1010

‣atmospheric** ν→μ5×104

‣astrophys (expct) ν→μO(10)

* 2000 per second

** 1 every 6 minutes

Alexander Kappes, ECRS’12, Moscow, 7. July 20127 cc

Neutrino telescope projects

IceCubeIceCube

BaikalBaikalBaikalBaikal

ANTARESANTARESANTARESANTARES

Text

KM3NeTKM3NeT(preparation phase)(preparation phase)KM3NeTKM3NeT(preparation phase)(preparation phase)

Alexander Kappes, ECRS’12, Moscow, 7. July 20128 cc

-1450 m

-2450 m

The IceCube observatory

Completed since Dec. 2010

‣ IceTopAir shower detector

‣ InIce86 strings (5160 PMTs)

Instrumented volume: 1 km3

‣Deep Coredensely instrumented

central region (8 strings)

→ see talk by H. Kolanoski

Alexander Kappes, ECRS’12, Moscow, 7. July 20129 cc

Detector history and status

Strings Year LivetimeTrigger

rate(Hz)

HE ν rate(per day)

AMANDA II (19)

2000−2006 3.8 years 100 ~5 / day

IC40 2008/09 375 days 1100 ~40 / day

IC59 2009/10 350 days 1900 ~70 / day

IC79 2010/11 320 days 2250 ~100 / day

IC86−I 2011/12 ~ 340 days 2700 processing

IC86−II current 2700 data taking

‣ IC86 uptime typical 99% (only 2% failed DOMs)

‣Detector sensitivity increases faster than # strings

Alexander Kappes, ECRS’12, Moscow, 7. July 201210 cc

Atmospheric neutrinos

‣High statistics sample~ 50.000 per year

‣Prompt componentstill unknown

‣Both signal andbackground(IC40)

Waxman&Bahcall bound astrophysical neutrinos

Alexander Kappes, ECRS’12, Moscow, 7. July 201211 cc

Cosmic diffuse neutrino fluxes

‣Search for excess inhigh energy tail

‣Requires knowledge ofprompt component

atm. ν

cosmic ν (E-2)

W&B bound

Cosmogenic neutrinos:p + CMB → n + π+

↳ μ+ + νμ

IC59

Alexander Kappes, ECRS’12, Moscow, 7. July 201212 cc

Cosmogenic neutrinos (IC79+86-I)

Optimized cuts for UHE neutrinos:

‣Expected background = 0.14(without prompt)

‣Observed = 2 (p-value 2.3σ)

Jan 3, 2012

Aug. 9, 2011

IC86-I

log10 NPE (energy proxy)

# e

vents

wit

hin

liv

eti

me

preliminary

background(no prompt)

predictions

prompt

Alexander Kappes, ECRS’12, Moscow, 7. July 201213 cc

Sensitivity UHE neutrinos (IC79+86-I)

‣Closing in on predictions

‣No significant excess so far

‣Substantial improvements in analysis anticipated

Stay tuned!

Alexander Kappes, ECRS’12, Moscow, 7. July 201214 cc

Skymap events (IC40+59)

‣IceCube is an all-sky telescope

‣Main sensitivity to sources in the northern sky

14

Northern hemisphere58,000 events

87,000 eventsSouthern hemisphere

atm

. muo

ns

PeV − EeV

atm

. neu

trin

os

TeV − PeVequatorial coordinates preliminary

Alexander Kappes, ECRS’12, Moscow, 7. July 201215 cc

Point sources: Significance skymap (IC40+59)

15

preliminary

67%

atm

. muo

ns

PeV − EeV

atm

. neu

trin

os TeV − PeV

Alexander Kappes, ECRS’12, Moscow, 7. July 201216 cc

Point sources: Selected sources (IC40+59)

preliminary

‣13 Galactic SNRs ... , 30 extragalactic AGNs

‣No significant excess (both all-sky and source list) up to now

‣Unblinding of IC79 data soon

Alexander Kappes, ECRS’12, Moscow, 7. July 201217 cc

Point sources: Sensitivities & upper limits

90% CL sensitivity / upper limits for E-2 spectrum

ANTARES

IceCube

KM3NeT

discovery region

Galactic γ-ray sources

Galactic Center

MACRO

Alexander Kappes, ECRS’12, Moscow, 7. July 201218 cc

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

ep n + π+

p + π0

γ (PeV)

ν (PeV)

internal shocks

collapse

γ (MeV)

Fireball model

10 100Energy [keV]

E2 ×

flux [

keV

cm

-2 s

-1]

10

10

01

00

01

GRB030329

10

4

Alexander Kappes, ECRS’12, Moscow, 7. July 201219 cc

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)

On-time (blind)

Off-time

Off-time

T0promptprecursor

(~100 s)

model independent

(several hours)

background

IC59: 98 bursts in northern sky

1 TeV 100 TeV 10 PeV

Waxman&Bahcall

Sum of 98 bursts

flux

Alexander Kappes, ECRS’12, Moscow, 7. July 201220 cc

GRBs: IceCube results (IC40+59)

Observed = 0

Expected = 8.4

prediction

90% UL

×3.7

E2 ×

flu

x [

GeV

cm

-2 s

-1

sr-1]

allowed

neutrino break energy [GeV]

high Γlow Γ

Are GRBs the sources of UHECRs?

Nature Vol. 484, 351 (2012)

Alexander Kappes, ECRS’12, Moscow, 7. July 201221 cc

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 !

Alexander Kappes, ECRS’12, Moscow, 7. July 201222 cc

Cosmic rays

Physics spectrum with IceCube

Cosmic acceleratorsCosmic accelerators Diffuse fluxesDiffuse fluxes Dark Matter & Exotic Physics

Supernovae Neutrino Properties &Particle PhysicsNeutrino Properties &Particle Physics→ see H. Kolanoski’s talk

Point-like sources(SNRs, Binaries ...)

Transient sources (GRBs, AGN flares...)

Extended sources

All-sky fluxes(e.g. cosmogenic)

Galactic plane

Extended structures(e.g. Fermi-Bubbles)

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

Alexander Kappes, ECRS’12, Moscow, 7. July 201223 cc

DeepCore

DeepCore

Dust layer

First steps into ν oscillations

DeepCore:

‣Decreases energy threshold to ~10 GeV

‣Look for standard oscillations

‣Strategy: Simple cuts and reconstructions

Top View

νμ disappearance

0°-45°

DeepCorelow energy

IceCubehigh energy

1 GeV

10 GeV

100 GeV

-90°

minimumminimum

Θ=0°

Θ=-90°

12,0

00

km

DeepCore low energy IceCube high energy

Θ=0°Θ=-90° Θ=-90° Θ=0°

systematics

cos(90°-Θ) cos(90°-Θ)

Alexander Kappes, ECRS’12, Moscow, 7. July 201224 cc

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

The IceCube collaboration