Results from the AMANDA Neutrino Telescope

CRIS06, Catania, June 2006

Juande D. ZornozaUniversity of Madison-Wisconsin

Neutrino Astronomy

• Photons interact with the CMB and with matter• Cosmic rays are deflected by magnetic fields and also interact with matter• Neutrons are not stable

High energy astronomy: Which probes can we use?

What else? Oh, yeah, neutrinos!

Photon and proton mean free range path

Neutrino CV

•Neutral•Stable•Weakly interacting*

*very large detectors needed

Production Mechanisms Gamma and cosmic ray astrophysics

are deeply related with neutrino astronomy:

YYKXN )(...)(

)()( eee

0 N X Y Y

Neutrino flavor rate: e:: ~ 1:2:<10-5 at the sourcee:: ~ 1:1:1 at the detector

Cosmic rays

Gamma ray astronomy

Scientific Scopes

??

Other physics: monopoles, Lorentz invariance, super-massive DM , SUSY Q-balls, etc...

~MeV

Supernovae

Average increase in the PMT

counting rate

TeV-PeV

Astrophysical sources(AGNs,

GRBs, MQs)

Up-going muons and cascades

PeV-EeV

AGNs, TD, GZK

neutrinos

Almost horizontal

tracks

EeV

?

Down-going tracks

Energy

Physics

Signature

GeV-TeV

Neutralino search

Up-going muons

AMANDA/IceCube Collaboration

USA (12)USA (12)Europe (13)Europe (13)

JapanJapan

New ZealandNew Zealand

• Bartol Research Institute, Delaware, USA• Pennsylvania State University, USA• UC Berkeley, USA• UC Irvine, USA•Clark-Atlanta University, USA• Univ. of Maryland, USA

• Bartol Research Institute, Delaware, USA• Pennsylvania State University, USA• UC Berkeley, USA• UC Irvine, USA•Clark-Atlanta University, USA• Univ. of Maryland, USA

• IAS, Princeton, USA• University of Wisconsin-Madison, USA• University of Wisconsin-River Falls, USA• LBNL, Berkeley, USA• University of Kansas, USA• Southern University and A&M College, Baton Rouge, USA

• IAS, Princeton, USA• University of Wisconsin-Madison, USA• University of Wisconsin-River Falls, USA• LBNL, Berkeley, USA• University of Kansas, USA• Southern University and A&M College, Baton Rouge, USA

• Universite Libre de Bruxelles, Belgium• Vrije Universiteit Brussel, Belgium• Université de Gent, Belgium • Université de Mons-Hainaut, Belgium• Universität Mainz, Germany• DESY-Zeuthen, Germany• Universität Dortmund, Germany

• Universite Libre de Bruxelles, Belgium• Vrije Universiteit Brussel, Belgium• Université de Gent, Belgium • Université de Mons-Hainaut, Belgium• Universität Mainz, Germany• DESY-Zeuthen, Germany• Universität Dortmund, Germany

• Universität Wuppertal, Germany• Uppsala university, Sweden• Stockholm university, Sweden• Imperial College, London, UK• Oxford university, UK• Utrecht,university, Netherlands

• Universität Wuppertal, Germany• Uppsala university, Sweden• Stockholm university, Sweden• Imperial College, London, UK• Oxford university, UK• Utrecht,university, Netherlands

• Chiba university, Japan• University of Canterbury, Christchurch, NZ

• Chiba university, Japan• University of Canterbury, Christchurch, NZ

South Pole

Runway

AMANDA-II

Amundsen-Scott South Pole Station

AMANDA Detector 1997-99: AMANDA-B10 (inner lines of AMANDA-II)

10 strings 302 PMTs

from 2000: AMANDA-II 19 strings 677 OMs 20-40 PMTs / string

At the surface: SPASE

Coincident events Angular resolution Cosmic ray

composition2 km

1 km

SPASE

trigger rate = 80 Hz

SignaturesCC- interactions:long (~km) tracks

NC- and CC-e/ interactions:cascades

7.0)TeV/(7.0 E (tracks short w.r.t. the inter-OM distance)

15 m

• Other signatures, like double bang, are expected to be more rare.

Background•There are two kinds of background:

-Muons produced by cosmic rays in the atmosphere (→ detector deep in the ice and selection of up-going events).-Atmospheric neutrinos (cut in the energy, angular bin…).

ee

Kp

...)(

ee

Kn

...)(

p

p

Ice Properties Shorter scattering length than in sea, but longer

absorption length (larger effective volume):

bubbles

dust

Absorption

dust

ice

Average optical ice parameters:

abs ~ 110 m @ 400 nmsca ~ 20 m @ 400 nm

Scattering

Moreover, very “silent” medium: dark noise < 1.5 kHz

Event reconstruction The position, time and amplitude registered by

the PMTs allows the reconstruction of the track, using Likelihood optimization techniques.

The angular resolution depends on the quality cuts of each specific analysis. For instance, in the point-like source search, it is 2.25-3.75 deg (declination dependent).

Once reconstructed the positions of the tracks, we can compare the number of events in each signal bin with the background at that declination.

example of AMANDA event

signal bin

background estimation

Sky map

The largest fluctuation (3.4) is compatible with atmospheric background

~92%

2000-2003 (807 days)

3329 s detected from Northern Hemisphere

3438 atmospheric s expected

Performance

aver

age

flu

x u

pp

er li

mit

[cm

-2s-1

]

sin

AMANDA-B10

AMANDA-II

Neutrino Effective Area Sensitivity to E-2 Point-like sources

• Sensitivity: Average upper limit, integrated above 10 GeV.• Steady increase with time.

•For E<10 PeV, Aeff grows with energy due to the increase of the interaction cross section and the muon range.•For E>10 PeV the Earth becomes opaque to neutrinos.

Ndet=Aeff × Time × Flux

AGNs: Stacking source analysis

single source sensitivity(four years)

Neutrino astronomy could be the key for establishing the hadronic/leptonic origin of the HE photons from AGNs.

Stacking-source analysis: The flux from AGNs of the same type integrated to enhance the statistics.

prel

imin

ary

No significant excess has been found. The stacking approach improves the one source limit by a factor three, typically.

Multi-wavelength approach Transient events also provide an opportunity to enhance sensitivity We can look for correlations with active periods from electromagnetic

observations: Blazars: X-rays Microquasars: radio

SourcePeriod wtih high activity

#events in high state

Expected background in high state

Markarian 421 141 days 0 1.63

1ES1959+650 283 days 2 1.59

Cygnus X-3 114 days 2 1.37

2000-03 data

sources: TeV blazars, microquasars and variable sources from EGRET

Transient sources When the variable character of the source is evident, but the EM

observations are limited, we can use the sliding-window technique. For the time-rolling source search, events in a sliding time window are

searched: Galactic: 20 days Extragalactic: 40 days

Source #events(4 years)

Expected background(4 years)

Period duration

Markarian 421 6 5.58 40 d

1ES1959+650 5 3.71 40 d

3EG J1227+4302 6 4.37 40 d

QSO 0235+164 6 5.04 40 d

Cygnus X-3 6 5.04 20 d

GRS 1915+105 6 4.76 20 d

GRO J0422+32 5 5.12 20 d

sources: TeV blazars, microquasars and variable sources from EGRET

Gala

cti

cExtr

ag

ala

cti

c

Orphan Flare Three events in 66 days within the

period of a mayor 1ES 1959+650 burst (orphan flare:s but no X-rays)

A posteriori search undefined probability of random coincidence.

sliding search window

Diffuse fluxes

Atmospheric neutrino spectrum is reconstructed using regularization-unfolding techniques.

No extraterrestrial diffuse component has been observed.E2 d/dE = 1.1 x 10-7 GeV cm-2 s-1 sr-1

(over the range 16 TeV to 2 PeV)

UHE neutrinos (I)

UHE neutrinos (>106 GeV) can be produced in several scenarios (AGNs, topological defects, GZK…)

>107 GeV the Earth is opaque to neutrinos search for horizontal tracks.

Background: muon bundles from atmospheric showers.

Neural network trained to distinguish between signal and background

simulated UHE event

UHE neutrinos (II)

Signal versus background: Signal produces higher light density There are more hits in UHE single muons, due to the

after-pulsing in the photomultipliers. Background events are produced mainly vertically down-

wards and signal events are expected to be horizontal. Different residual time distributions (because of after-

pulsing) Center of gravity of hits pulled away from the geometrical

center of the detector for down-going bundles.

UHE neutrinos (III) 2000 data used for this analysis:

20% for the optimization of cuts 80% after unblinding is approved

There is a factor two of improvement in the sensitivity w.r.t. AMANDA B10

Limit = 3.710-7 GeV cm-2 s-1 sr-1

(from 1.8105 to 1.8109 GeV)

UHE neutrinos (IV)

PRELIMINARY sensitivities to different models of UHE production:

Source

Number expected in 80% of 1 year

(138.8 days)all

MRF for 80% sample(FC = 3.49)

AGN core (Stecker et al 96) 37.0 0.09

AGN core (Stecker et al 92) 8.9 0.39

AGN jet (Protheroe 96) 8.9 0.40

AGN jet (Halzen and Zas 97) 8.5 0.41

Z-Burst (Kalashev et al 02) 3.6 0.96

Mono-Energetic p-γ (Semikoz 03) 0.65 5.4

Topological Defect (Sigl et al 98) 0.63 5.5

E-2 p-γ (Semikoz 03) 0.45 7.8

Z-Burst (Yoshida et al 98) 0.15 24.0

p-γ (Engel et al 01) 0.012 298.8

L. Gerhardt

SGR 1806-20

We try to observe down-going muons produced by TeV photons discriminating the background of atmospheric muons using an

angular and a time window

RA (J2000) 18h 08m 39.4s = 272.16 deg

DEC (J2000) -20deg24'39.7" = -20.41 deg

SatelliteTrigger time at Earth

(ms)

GEOTAIL 21:30:26.71

INTEGRAL 21:30:26.88

RHESSI 21:30:26.64

CLUSTER 4 21:30:26.15

Double Star 21:30:26.49

Duration < 0.6 s

Time window 1.5 s0.4 s

The SGR 1806-20 flare (Dec. 2004) was more than The SGR 1806-20 flare (Dec. 2004) was more than one order of magnitude more powerful (2x10one order of magnitude more powerful (2x104646 erg) than previous flares: detectors saturated.erg) than previous flares: detectors saturated.

+

Swift-BAT light curveSwift-BAT light curve

SGR 1806-20

MDF have jumps when we have to increase the (discrete) number of events needed to satisfy the condition of 5 confidence interval.

MRF behaves smoothly since only the mean expected background in taken into account.

5 events, time window: 1.5 s Confidence interval=5Statistical Power=90%

DiscoveryDiscovery Optimum cone size: 5.8°Optimum cone size: 5.8°

Best MDF: 2.3Best MDF: 2.3

Observed events Observed events needed: 4needed: 4

Background: 0.06Background: 0.06

SGR 1806-20

neutrinos

gammas

• Limits in the constant of a d/dE=A E-1.47 flux are set, constraining both the HE gamma and neutrino emission.

preliminary

Effective areas Limit in flux normalization

Unfortunately, no event was found after unblinding, so upper limits have been calculated.

GRBs (average spectrum) Search time window: from 10 sec

before the burst start to the end of the burst.

Precursor: from -110 sec to -10 sec. Background estimation: from 1

hour before to 1 hour after (except 10 minutes around the burst which remain unblinded)

years # GRBs selection criterion limit (GeV cm-2 sr-1)

97-00 312 BATSE 410-8

00-03 139BATSE + IPN

310-8

00-03 (with precursor) 50 510-8

00 74 BATSE 9.510-7

Neutralino Search

WIMPs would scatter elastically in the Sun or Earth and become gravitationally trapped.

They would annihilate producing standard model particles.

Among the annihilation products, only neutrinos can reach us.

Neutralinos annihilate in pair-wise mode:

2

2ann

ann m

v

ann: annihilation rate per unit of volumeann: neutralino-neutralino cross-sectionv: relative speed of the annihilating particles: neutralino mass densitym: neutralino mass

HWHZHHZZWWll , , , , , 02,1

003

02,1

00

and neutrinos are produced as secondaries.

Neutralino Search

excluded by Edelweiss

The Sun is the most promising source of neutralinos.The Sun is the most promising source of neutralinos.Neutralino density in the Earth is diminished the effect of the Neutralino density in the Earth is diminished the effect of the Sun mass.Sun mass.

Conclusions AMANDA has been operating for almost one

decade. No extraterrestrial neutrino has been observed

above the atmospheric background,

Increasingly stringent limits have been set in point-like sources, diffuse fluxes, neutralinos…

A bigger detector is needed IceCube (already in construction!)

but sometimes success comes after much work and patience!

YET…

Thanks to the organizers!

Backup transparencies

Particle Physics

Monopoles Monopoles would also give a large signal in the detector, which can be

discriminated from high energy muons. Two signatures are possible:Direct emission (βm>0.74): ×8500 wrt muonInduced δ-ray emission (βm>0.51)

GRB model parameterization

b

s

'A

FA

ztF

zEss

bb

,,

,

1

1

90

0

GRBs (individual spectrum)

The individual spectrum can be used instead of the average to enhance the sensitivity for a given burst.

The parameters of the Band function of the GRB030329 burst were calculated.

0.0350.036average (WB) (3)

0.0390.041beamed (2)

0.1500.157isotropic (1)

Limit

(GeV s-1 cm-2)

Sensitivity

(GeV s-1 cm-2)

Model

12

3

neutrino energy flux (GeV cm-2 s-1)

GRBs: individual bursts

AGN models Low energy (from radio up to UV / X-

ray): non-coherent synchrotron radiation. High energy (up to TeV) under debate:

leptonic versus hadronic models.