20th International Workshop on Weak Interactions and Neutrinos (WIN'05)

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20th International Workshop on Weak Interactions and Neutrinos (WIN'05)

http://amanda.uci.edu http://icecube.wisc.edu

Neutrino Astronomy at the South PoleLatest results from AMANDA and perspectives for IceCube

Paolo [email protected]

University of Wisconsin – Madison

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Bartol Research Inst, Univ of Delaware, USAPennsylvania State University, USAUniversity of Wisconsin-Madison, USAUniversity of Wisconsin-River Falls, USALBNL, Berkeley, USAUC Berkeley, USAUC Irvine, USA

Univ. of Alabama, USAClark-Atlanta University, USAUniv. of Maryland, USAIAS, Princeton, USAUniversity of Kansas, USASouthern Univ. and A&M College, Baton Rouge, LA, USAInstitute for Advanced Study, Princeton, NJ, USA

Université Libre de Bruxelles, BelgiumVrije Universiteit Brussel, BelgiumUniversité de Mons-Hainaut, BelgiumUniversiteit Gent, BelgiumUniversität Mainz, Germany

DESY-Zeuthen, GermanyUniversität Wuppertal, GermanyUniversität Dortmund, GermanyHumbolt Universität, GermanyUppsala Universitet, Sweden

Chiba University, Japan

University of Canterbury, Christchurch, New Zealand

Who is in IceCube ?

Stockholm Universitet, SwedenKalmar Universitet, SwedenImperial College, London, UKUniversity of Oxford, UKUtrecht University, Netherland

Amundsen-Scott Station, Antarctica

3Amundsen-Scott South Pole Station

South PoleDome

Summer camp

AMANDA

road to work

1500 m

2000 m

[not to scale]

Where are we ?

IceCube

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PMT noise: ~1 kHz

AMANDA-B10(inner core of AMANDA-II)

10 strings302 OMs

Data years: 1997-99

Optical Module

“Up-going”(from Northern sky)

“Down-going”(from Southern sky)

AMANDA-II19 strings677 OMs

Trigger rate: 80 HzData years: >=2000

PMT looking downward

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AMANDA

IceCube

IceTop

IceCube80 strings

60 OMs/string17 m vertical spacing

125 m between strings

IceTop160 tanks

frozen-water tanks2 OMs / tank

First year deployment (Jan 2005) 1 IceCube string (60 OMs)8 IceTop Tanks (16 OMs)

10” Hamamatsu R-7081

1200 m

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Event detection in the iceO(km) long tracks

~17 m

cascades

Longer absorption length → larger effective volume

AMANDA-II

trackspointing error : 1.5º - 2.5º

σ[log10(Eμ/TeV)] : 0.3 - 0.4

coverage : 2Cascades (particle showers)

pointing error : 30º - 40º

σ[log10(Ec/TeV)] : 0.1 - 0.2

coverage : 4

cosmic rays (+SPASE)combined pointing err : < 0.5º

σ[log10(Ep/TeV)] : 0.06 - 0.1

Nucl. Inst. Meth. A 524, 169 (2004)

event reconstruction by Cherenkov light timing

South Pole ice: the most transparent natural

medium ?

a neutrino telescope

0.65o(E/TeV)-0.48

(3TeV<E<100TeV)

abs> ~ 110 m @ 400 nm

sca> ~ 20 m @ 400 nm

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ν astronomy : physics goals

• Protons which escape are bent => cosmic rays

• Photons which escape are absorbed above 50 TeV

• Neutrinos escape

AMANDA

IceCube

Bottom-Up scenariocosmic acceleratorp + (p or ) + X e , + X

Energy Eν-2 (fermi acceleration)

Atm. ν Eν-3.7 (energy separation)

Array

Still no evidence of TeV detection from o production

Neutrino detection would demonstrate hadronic processes

• steady and transient point sources (point resolution)• unresolved faint neutrino sources (diffuse ν)• expected extraterrestrial ν require km3 scale detectors !

• background rejection• good acceptance• high sensitivity

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ν astronomy : background

Background rejection

Cosmic ray μ main background




Up/Down EnergySource

directionArrival

timeCount rates

Atmospheric ν ×Diffuse ν,

Cascades,

UHE events× ×

Point sources:

AGN, WIMPs × × ×GRB × × × ×

Supernovae ×

Preliminary

data/mc ~ +30%normalized

(statistical errors)

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ν astronomy : background

Atmospheric background & calibration beamFirst energy spectrum > 10 TeVBlobel regularized unfolding




Preliminary

importance of high energy prompt leptons background from charm still uncertain

Expected high energy flux

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telescope : AMANDA event

energy deposited in OM

time recorded on OM

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Detection of from discrete steady bright or close sources (AGN, …)

• binned optimization in δ bands, versus a given signal hypothesis ( E-2)• cosmic ray μbackground rejection• good pointing resolution (good quality events)• possible event-energy selection

telescope : point source search

signal bin

background estimation

• background estimated from exp data with randomized α (i.e. time)• signal obtained from full simulation• obtain best sensitivity (average upper limit)

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detector AMANDA-II IceCube

pointing resolution

1.5° ↑ -2.7° → ~0.7° (> 10 TeV)

bin search radius

3.6°3.6° (min)

8.8°8.8° (max)

~ 1°

μ effective area

~0.025 km2 (@ 10 TeV)

~ 0.8 km2 (> 10 TeV)

~1.2 km2 (> 100 TeV)

AMANDA-II - 2000-02 (607 days)

declination 0o

90o

1 m2


Detection of from discrete steady bright or close sources (AGN, …)

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Average upper limit = sensitivity (δ>0°)(integrated above 10 GeV, E-2 signal)

(*) optimized for E-2, -3 signal

1997 : ApJ 583, 1040 (2003) 2000 : PRL 92, 071102 (2004)

2000-02 : PRD 71 077102 (2005)

IceCube : Astrop Phys 20, 507 (2004)

ave

rag

e fl

ux

up

per

lim

it [

cm-2s-1

]

sin

AMANDA-B10

AMANDA-II

Sensitivity independent of direction

increases almost linearly with exposure

*

lim 0.68·10-8 cm-2s-1

declination 0o

90o

ave

rag

e fl

ux

up

per

lim

it [

cm-2s-1

]

sin

AMANDA-B10

AMANDA-II

IceCube 1/2 year

*

Preliminary

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PRD 71 077102 (2005)

AMANDA-II - 2000-02 (607 days)

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Preliminary

Search for clustering in northern hemisphere• compare significance of local fluctuation to atmospheric expectations• un-binned statistical analysis• no significant excess

2000-2003 (807 days)

3329 from northern hemisphere

3438 expected from atmosphere

~92%

Maximum significance 3.4

compatible with atmospheric

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telescope : unresolved sources ?neutrinos from single steady sources may be as many as background

enhance detection using:

• stacking steady point source candidates (on the wayon the way)• catalogue of possible neutrino emitter AGN candidates and selection optimization on the ensamble to enhance sensitivity

• time correlation with transient phenomena (preliminary results)• known active flary periods of TeV gamma sources• time-rolling search of signal excess over background

• diffused flux of neutrinos with no time-space correlations (preliminary preliminary resultsresults)

• calculate upper limit on high energy tail of atmospheric νμ

• optimize selection with attention to background(s) rejection• multi-flavor (muon tracks + cascades)

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telescope : point source searchDetection of from known active flary periods

• periods (during 2000-03) and sources selected on the basis of the available multi-wavelength information• the wavelengths investigated are possible indicators for a correlated neutrino emission (X-ray for Blazars and radio for Microquasars)

• based on hypothesis neutrinos are emitted in coincidence with electromagnetic flare emissions

Source EM light curve source

Livetime in periods of

high activity

Nr. of n events in

high state

Expected backgr. in high state

Markarian 421 ASM/RXTE 141 days 0 1.63

1ES1959+650 ASM/RXTE 283 days 2 1.59

Cygnus X-3 Ryle Telesc. 114 days 2 1.37

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telescope : point source searchDetection of with time rolling search

events

time

sliding window • time window: 40 / 20 days for Extragalactic / Galactic Objects

• angular bin: 2.25°-3.75°

Source Nr. of n events

(4 years)

Expectedbackgr.

(4 years)

Period duration

Nr. of doublets

Chance probability

Markarian 421 6 5.58 40 days 0 1

1ES1959+650 5 3.71 40 days 1 0.34

3EG J1227+4302

6 4.37 40 days 1 0.43

QSO 0235+164 6 5.04 40 days 1 0.52

Cygnus X-3 6 5.04 20 days 0 1

GRS 1915+105 6 4.76 20 days 1 0.32

GRO J0422+32 5 5.12 20 days 0 1

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telescope : diffused sources

• no space-time correlation which helps in rejecting background

• signal hypothesis with harder energy spectrum than background (Fermi acceleration)

10-6 × E-2

E-3.7

• requires good understanding of background(s)

• requires detector systematics to be under control

• relies on simulation of background and signal events

• sensitivity to high energy tails (up to ~ PeV)

# hit Optical Modules

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telescope : diffused sources

• energy reconstruction with NN

• acceptance correction with regularized Blobel unfolding

• confidence interval construction according to FC prescription

• set upper limit on last bin

• ΦνE2 < 2.6 × 10-7 GeV cm-2s-1sr-1 (100 TeV < E < 300 TeV)

extending to longer exposure (2000-03)

Preliminary

year 2000

• optimization on observables for background rejection and event quality

• energy estimator is the number of hit OM

• best expected sensitivity (2000-03) : ΦνE2 < 9 × 10-9 GeV cm-2s-1sr-1 (10 TeV < E < 5 PeV)

νμ : 2π coverage

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telescope : diffused sourcesCascades: 4π coverage

Nobs = 1 event

Natm μ = 0.90

Natm ν = 0.06 ± 25%norm

+0.69-0.43+0.09 0.04

After optimized cuts:

Ast

ropa

rtic

le P

hysi

cs 2

2 (2

004)

127

background

νe signal

year 2000

E ~160 TeV

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telescope : diffused sourcesUHE: 4π coverage

Ast

ropa

rtic

le P

hysi

cs 2

2 (2

005)

339

• Earth opaque to PeV neutrinos

→ look up and close to horizon

• Look for very bright events (large number of Optical Modules with hits)

• Train neural network to distinguish E-2 signal from background

Nobs = 5 events

Nbgr = 4.6 ± 36% events

Simulated UHE event

ΦνE2 < 0.99·10–6 GeV cm-2 s-1 sr-1 (1 PeV < E < 3 EeV)

year 1997 (AMANDA-B10)

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all-flavor limits

diffuse (B10 1yr)

diffuse (A-II 4yr)

diffuse (A-II 1yr)

cascade (A-II 1yr)UHE (B10 1yr)

cascade (B10 1yr)

telescope : diffused summary

• limits on all-flavor

• limits on E-2

• would need to model other spectra

x3

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telescope : Galactic Plane

• interaction of CR in interstellar medium expected to produce a flux of neutrinos from the galactic disk • same energy spectrum as CR E-2.7

• modelled πo component of γ rays in 4GeV < E < 10GeV has σ~2.1o in galactic latitude (Strong et al., ApJ 613, 2004)

• AMANDA-II angular resolution ~ 1.5o – 2.5o

• ~constant column density in visible galactic longitude

→ gaussian-distributed line source of neutrinos from the galactic disk, gaussian-distributed line source of neutrinos from the galactic disk,

isotropic in galactic longitudeisotropic in galactic longitude • sensitivity optimized by an appropriate choice of the on-source region width (i.e. galactic latitude width)

• optimal region width is 4.4o (contains >90% of signal)

• 90% of selected events in energy range 130GeV < E < 30 TeV

• preliminary sensitivity significantly above predictions

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telescope : Gamma Ray Bursts

• use space-time localization of the events. Two approaches underway:

• Waxman-Bahcall average spectrum hypothesis

• νμ search using 312 BATSE bursts (1997-2000) & 139 BATSE+IPN bursts (2000-2003)• preliminarypreliminary upper limits (of νμ) at Earth:

•1997-2000 ΦνE2 < 4 × 10-8 GeV cm-2 s-1 sr-1

• 2000-2003 ΦνE2 < 3 × 10-8 GeV cm-2 s-1 sr-1

• ongoingongoing all-flavor search using 74 BATSE bursts (2000)• ongoingongoing cascade-like time rolling search with no external trigger (2001)

• burst-specific prompt spectrum hypothesis

• ongoingongoing νμ search using 200 BATSE bursts (1997-2000)• GRB030329

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Indirect WIMP detection

Sun

Earth

Detector

Freese, ’86; Krauss, Srednicki & Wilczek, ’86 Gaisser, Steigman & Tilav, ’86

Silk, Olive and Srednicki, ’85Gaisser, Steigman & Tilav, ’86

velocitydistribution

scatt

capture

annihilation

interactions

int. int.

qq

ll

W, Z,H

interactions hadronization

cc ,bb ,tt , ,W, Z 0, HH 0

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Indirect WIMP detection

Disfavored by direct search(CDMS II)

Limits on muon flux from Earth center Limits on muon flux from Sun

PRELIMINARY

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from SupernovæSNEWS is a collaborative effort between Super-K, SNO, LVD, KamLAND, AMANDA, BooNE and several gravitational wave experiments

Bursts of low-energy (MeV) neutrinos from core collapse supernovae

AMANDA detection: - simultaneous increase of all PMT count rates (~10 s) - can detect 90% of SN within 9.4 kpc - less than 15 fakes per year

detection

radius

AMANDA-II

AMANDA-B10

IceCube30 kpc

AMANDA-B10 sees 70% of the galaxy

AMANDA-II sees 90% of the galaxy

IceCube will see out to the LMC

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IceCube: the future• first IceCube string deployed (60 Digital OM)• first 4 IceTop Stations deployed (8 tanks/16 Digital OM)

DOM being deployed in the ice

DOM in the tank ice

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An IceCube-IceTop event

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An AMANDA-IceCube event

• verification of newly deployed string

• off-line synchronization of AMANDA and IceCube data

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IceCube deployment plan

January 05:

• Strings: 1

• Tanks/stations: 8/4

05/06 Plan*:

• Strings: 10 - 12

• Tanks/stations: 24/12

runw

ay

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Neutrino flavor identification

Neutrino flavor

Log(ENERGY/eV)

12 18156 219

e

e

supernovaeFull flavor ID

Showers vs tracks

AMANDA flavor ID

IceCube flavor ID,direction, energy

IceCube triggered,partial reconstruction

Tau Neutrinos:• Regeneration: earth quasi-

transparent to

• Enhanced & cascade flux due to secondary , e

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IceCube flavor neutrino detection

Eµ = 10 TeVe e E = 375 TeV

~300m for 10 PeV t

μ μ

τ τ + “cascade”

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IceCube high energy extension

in AMANDA

in IceCube

Simulated 2×1019 eV neutrino event

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SummaryNo Extraterrestrial neutrino signal observed yet !No Extraterrestrial neutrino signal observed yet !

• AMANDA-II upper limits getting tighter and constraining models• higher event statistics• good ice properties understanding• improving background rejection capabilities• still improving reconstruction event quality• toward clean atmospheric νμ measurement as backgroundbackground• improve strategies for sensitivity enhancement

• IceCube/IceTop in verification phase (engineering data and preliminary tests)• IceCube/IceTop will significantly improve astrophysics and cosmic rays

measurements in energy range and resolution• IceCube will be a powerful all-flavor neutrino detector (particle physics)• IceTop will open the CR measurements up to ~ EeV with high resolution• use of PMT waveforms is a new tool we are learning to use

• AMANDA will overlap the lower energy tail of IceCube sensitivity

42“The “ @ South Pole

thank you

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IceCube : simulated track events

back

Eµ=6 PeV, 1000 hitsEµ=10 TeV, 90 hits

20th International Workshop on Weak Interactions and Neutrinos (WIN'05)

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