Status of the ANTARES Neutrino Telescope

Stéphanie ESCOFFIERCPPM Marseille, France

on behalf of the ANTARES Collaboration

• research goals

• detector setup

• selected results

• summary

S. Escoffier – Status of the ANTARES telescope - TeVPA 2011 - Stockholm 2

Neutrino astronomy

Cosmic sources of neutrinos• micro quasars: X-ray binaries • supernova remnants and shock acceleration• Active Galactic Nuclei• Gamma Ray Bursts

Intriguing science questions:• astrophysical acceleration mechanism ?• origin of cosmic rays ?• dark matter ?• other exotic physics (magnetic monopoles) ?


The ANTARES Collaboration

CPPM, Marseille DSM/IRFU/CEA, Saclay APC, Paris LPC, Clermont-Ferrand IPHC (IReS), Strasbourg Univ. de H.-A., Mulhouse IFREMER, Toulon/Brest C.O.M. Marseille LAM, Marseille GeoAzur Villefranche

IFIC, ValenciaUPV, ValenciaUPC, Barcelona

NIKHEF (Amsterdam) KVI (Groningen) NIOZ Texel

University of Erlangen Bamberg Observatory

ISS, Bucarest

ITEP, Moscow Moscow State

Univ

7 COUNTRIES7 COUNTRIES28 INSTITUTES28 INSTITUTES

~ 150 SCIENTISTS AND ~ 150 SCIENTISTS AND ENGINEERSENGINEERS

University/INFN of Bari University/INFN of

Bologna University/INFN of

Catania LNS – Catania

University/INFN of Pisa University/INFN of Rome

University/INFN of Genova


The ANTARES detector

~60 m

350 m14.5 m

Submarine links

JunctionBox

40 km toshore

BuoyStorey

Completed in May 2008

• 12 lines of 75 PMTs• 25 storeys / line• 3 PMTs / storey• ~900 PMTs


Optical background• constant 40K (~40 kHz)

The background

2 min

PMT counting rates

40K

40Ca

e-

Cherenkov light

beta decay

40K is used to check the time calibration of the detector

• bioluminescence of micro-organisms• bursts from macro-organisms

(Particle) Physics background

• cosmic rays (atmospheric μ and ν)




The background

2 min

PMT counting rates

strongly correlated to sea currents





The background

2 min

PMT counting rates


special event in 2006:ANTARES Coll.,Deep-Sea Res. I 58 (2011) 875.




The online/precise trackingOnline tracking • fast, to discriminate atmospheric muons from neutrinos• No detailed calibration/ no real time detector positioning needed• Angular resolution: Δθ 3o

The precise tracking• detailed real-time positioning of the detector• detailed PMTs charge/time calibration• detailed systematic knowledge of the apparatus (OMs angular acceptance, etc.)• Angular resolution: up to Δθ0.2o

arXiv 0908.0816

Astropart.Phys. 34 (2011) 652


Event display: a neutrino candidate

Example of a reconstructed up-going muon (i.e. a neutrino candidate) detected in 6/12 detector lines:

time

height

online tracking

•atmospheric muon flux•atmospheric neutrinos•point sources see talk by Juan Pablo

Gomez •diffuse νμ flux•magnetic monopoles

•dark matter see talk by Juande Zornoza


Atmospheric muons

online tracking

Zenith angle distribution of reconstructed tracks from atmospheric muons with a 5 line detector.

Astropart.Phys. 34 (2010) 179.

Within systematic uncertainties the measurements cannot distinguish between the models considered

• systematic error due to +/- 10% on absorption length = +25%/-20%;• syst. err. due to -15% on PMT efficiency (QE, eff. area etc) = -15%;• syst. err. due to cutoff in angular accept. = +20%/-15%;• total systematic uncertainty +/- 30%.Systematic uncertainties: +30% primary flux; +25% hadronic interaction model

DataMC (corsika + qgsjet)Systematics on MC

corsika + qgsjet (poly)corsika + sibyllmupage


Muon depth-intensity relation

Astropart.Phys. 34 (2010) 179.

Results are in agreement, within the systematic uncertainties, with the theoretical predictions and previous measurements

2,5km6km


Atmospheric neutrinos

341 days detector live time,single- and multi-line fit

elevation angle

up-going

good agreement with Monte Carlo • atmospheric neutrinos: 916 (30% syst. error)

• atmospheric muons: 40 (50% syst. error)

1062 cand.

down-going

1062 neutrino candidates: 3.1 candidates/day

online tracking

data set:2007-2008 data taken with 5 lines (2007)and 9, 10, and 12 lines (2008)


Search for point-like sources

Well reconstructed

Badly reconstructed

uncertainties inangle reconstruction: median: 0.5 0.1O

12-line data: 0.4 0.1O

absolute orientation: 0.1O

data set:2007-2008 data taken with 5 lines (2007)and 9, 10, and 12 lines (2008)

precise tracking

arXiv:1108.0292v1 [astro-ph.HE]

S. Escoffier – Status of the ANTARES telescope - TeVPA 2011 - Stockholm 15H. Löhner, High Energy Neutrino Flux 15

Search for point-like sourcesEquatorial coordinates

Two distinct approaches:• all sky search• list of candidates

24 source candidates

point-like sources search see J. Gomez’s talk

arXiv:1108.0292v1 [astro-ph.HE]


Search for diffuse νμ flux

no excess of high-energy events above expected flux from atmospheric

background from atmospheric : ~ E-3.5

+ prompt neutrinos

cosmicneutrino models: ~ E-2

search for high-energy diffuse-flux tail

Phys. Lett. B 696 (2011) 16.

Energy estimate R based on extra light fromdelayed OM hits due tohigh-energy EM showers


Diffuse flux: upper limits

Upper limit is E2(E)90%= 4.8×10-8 GeV cm-2 s-1 sr-1 for 20 TeV<E<2.5 PeV

Phys. Lett. B 696 (2011) 16.

(334 days of equivalent live time)


Search for magnetic monopoles

Magnetic monopoles emit 8500 more Cherenkov light than a muon can be detected by ANTARES

Two estimators to discriminate MM from atmospheric background• The number of hits estimates the quantity of light• The ratio of two tracking reconstruction,

where χ2β=1 standard muon

algorithm (β =1)

χ2β modified algorithm (β

free)

λ=log(χ2β=1 /χ2

β)

Selection optimized for the discovery potential (in a blind way)


Monopoles: upper limits

no excess of events above the expected atmospheric background flux

Upper limit is (E)90%= 1.3×10-17 cm-2 s-1 sr-1 at β≈1

(116 days of equivalent live time with 2008 data)


Multimessenger astronomy

GCNGRB Coord. Network:γ satellites

SNEWSSuperNova Early Warning System

Ligo/VirgoGravitational waves:trigger + dedicatedanalysis chain

TaToOoptical follow up

Strategy• higher discovery potential by observing different probes• higher significance by coincidence detection• higher efficiency by relaxed cuts


TAToO projectTAToO

Optical follow-up of neutrino alerts from ANTARES in order to search for and identify transient sources (GRB, AGN flares…)

ν

ANTARES

Reconstruction “on-line” (<10ms)Trigger: multiplet / HE singlet Alert neutrino (GCN)

Real time

send <10s

1.9° x 1.9°

Large sky coverage (>2π sr) + high duty cycleImproved sensitivity (1 neutrino may lead to a discovery !!!)No hypothesis on the nature of the sourceNon dependent on the availability of external triggers

Advantages:

Tarot and ROTSE


Future plans: KM3NeT concept

array of multi-PMToptical modules (OM)sensing Cherenkov light

instrumented volumeseveral km3

sensitive to all flavours

E > 0.1 GeV

angular resolution min 0.1o for E > 10 TeV

acceptance: up-going tracks,up to 10o above horizon

•ANTARES completed since May 2008•complements the sky coverage of IceCube•has a broad physics program•new diffuse-flux limit•competitive new magnetic monopoles flux

limit•multi-messenger observations on alert•paves the way for KM3NeT

Documents

Status of the ANTARES Neutrino Telescope