Neutrino telescopes in

the Mediterrane

an sea

Marco AnghinolfiINFN-Genovaon behalf of the ANTARES

CollaborationHEP2012Vlaparaiso, January

2012

The ANTARES detector

Results and physics analisys in ANTARES

The goals

Amst

erda

m -

30 M

arch

201

1Th

. Sto

larc

zyk

- CEA

Irfu

2

p/A + p/g p0 + p + ... gHE gHE nm m n m ne e

e + g e + gHE (inverse Compton)

Pulsars

Supernova remnants

AGN

Microquasars

GRB

• Origin of cosmic rays• Understanding of know sources• Unknown phenomena

GalacticExtra-

Galactic

Detection PrincipleNeutrinos (E > 100GeV)can be detected using the visible Cherenkov radiation produced as the high-energy charged leptons (final state of CC interactions) propagate through a transparent medium with superluminal velocity.

p

~103 atm.

p,

107

atm.per year

cosm.

Signal to noise

The sky coverage of ANTARES

• 42°50’ North• 6°10’ East• 2500 m

depth

The ANTARES detector

A typical up-going event

How does a muon look like?

EnvironmentalBackground

Reconstructed up-going events/day

Neutrinos (multi-line, single-line) per day

single line

multi line

Period with high bioluminescence

full 12 line connection

5-line data (May-Dec. 2007)+ 9-12 line data (2008)

reconstruction BBfit v3r2,single- and multi-line fit

elevation angle

down-goingup-going

good agreement with Monte Carlo: atmospheric neutrinos: 916 (30% syst. error)atmospheric muons: 40 (50% syst. error)

1062 cand.

Comparison to Monte Carlo

11

Well reconstructed

Badly reconstructed

uncertainties inangle reconstruction:

median: 0.5O

12-line data: 0.4O

absolute orientation: 0.1O

data set:2007-2008 data

taken with 5, 9, 10, and 12 operating detector lines

Search for point-like n sources

Full-sky search

12

Most significant cluster at: RA= ‒46.5°, δ= ‒65.0°

Nsig = 5Q = 13.02p-value = 0.026Significance = 2.2 σ

Sky map in Galactic CoordinatesBackground colour indicates visibility

Result compatible with the background hypothesis

Blue points: 3058 selected events

Red stars: candidate source list

Best Limits for the Southern sky

Assuming an E-2 flux for a possible signal

ANTARES 2007-2010 813 days × 2.5 improvement w.r.t.previous analysis (304 days)

For most of the sources ANTARES gives the most stringent limits.(IceCube requires veryhigh energy component (E >1 PeV) for Southern Sky).

Rencontres de Moriond 2011 M. Vecchi

Search for a diffuse cosmic flux Idea:Background atmospheric neutrinos have a steeply falling energy spectrum: N ~E-3.5

Many cosmic neutrino model predict much harder spectra, typically N ~E-2

→ Look for high– energy diffuse flux component

Analysis:•Live time: 334 days (2007-2009)•Stringent selection: 134 high energy n candidates, no atmospheric m’s•Energy estimator R: a measure of the number of delayed photons

•High energy muons can produce more than one hit in the same PMT

Results on diffuse cosmic flux

On-going Physics analysesn flux from Fermi bubbles

Fermi bubbles

Two scenarios:•Su et al.: bubbles due to highly relativistic electrons emitting sincrotron radiation (GHz-WMAP) and simultaneously produce inverse-Compton grays.

•M.Crocker & F.Aharonian: bubbles due to hadronic process : CR protons associated with long timescale star formation in the GC and injected in the bubbles by star wind HE neutrinos

Fermi bubbles

•If the hadronic scenario is confirmed FBare possible HE neutrino sources for telescopes in the Mediteranean sea.

•Very extended source: same analysis of diffuse neutrino flux. Need to discriminate according to energy.

•Analysis just started: expectedflux limits soon

Searches for Neutrinos from GRB

Triggered search method:

•Dedicated low level trigger after a gamma-ray satellite alert (GCN)

•Requires Satellite trigger

•Low backgrounds due to direction and time coincidences

•Search for muons produced by neutrinos in correlation with gamma-ray :candidate tracks are required to point back tothe GRB position to within 2° and to occur during the arrival of prompt photons.

•37 GRBs in the analysis applied to the data taken during the alerts occurred in 2007.

• No neutrino candidate muons were observed in correlation with the GRBs.

• The limits placed on the average flux of these bursts at the 90% confidence level, for three different GRB models

• A second search uses an alternative method to identify the shower at the neutrino-interaction vertex. This search is particularly sensitive to electron-neutrinos.

90% CL Upper limits on nu fluxes from 37 GRBs

Searches for Neutrinos from GRB

21

Transient sources: Flares

•Motivation: Fermi data shows a extremely variable HE universe

•Main goal: Selects flares from Fermi catalog & look for coincidences: strong correlation between the gamma-ray and the neutrino fluxes is expected

•Method: adapt the un-binned method used in the point-like source by adding a time PDF

•Data: FERMI: started July 2008 => used the data taken with the full 12 lines ANTARES detector during the last four months of 2008.

Gamma-ray light curve of the blazar3C454.3 measured by Fermi above 100 MeV for almost 2 years of data

Transient sources: Flares•Selection: sources located in the visible part of the sky by Antares from which the averaged one day-binned flux in the high state is greater than 20 10-8 photons.cm-2 s-1 above 300 MeV .

•Most significant event: one neutrino event has been detected in time/spacecoincidence with the gamma-ray emission from the flare 3C279p-value of about 10 %, still compatible with background fluctuations

•Perspectives: the most recent measurements of Fermi in 2009-11 show very large flares yielding to apromising search of neutrinos

Gamma-ray light curve of the blazar 3C279. The red bar is the time of the ANTARES neutrino event

ANTARES & AUGER

•ultra high energy cosmic rays are expected to be accompaniedby gamma-rays and neutrinos from pion decays

•field of view for the ANTARES telescope andthe Pierre Auger Observatory (PAO) greatly overlap.

•correlation of arrival directionsof 2190 neutrino candidate events detected by 5-12line ANTARES neutrino telescope, and 69 UHECRs observedby the PAO

ANTARES & AUGER

The most probable count for the optimized bin size of 5.2°is 343.34 events in all 69 bins with standard deviation of 15.69 events.

After unblinding 2190 Antares neutrino candidate events,a count of 315 events within 69 bins is obtained NO CORRELATION found

Circles: 5.2 ° bins centered on UHECRs observed by AUGER.

Black triangles: ANTARES neutrino events correlating with observed UHECRs (inside bin)

Pink crosses : ANTARES neutrino events outside the bins

Multi-Messenger astronomyStrategy:higher discovery potential by observing different probesHigher significance by coincidence detectionHigher efficiency by relaxed cuts

GCNGRB Coord. Network:γ satellites

Alerts

Ligo/VirgoGravitational waves:trigger + dedicatedanalysis chain

TAROToptical follow up:10 srepositioning

MoUs for joint research

An exemple: optical follow-up Alerts sent by ANTARES

• High energy (nhits& amp)expected ~ 2/month

TAROT: 2 telescopes•Diameter: 25 cm•Field of view: 1.86°×1.86°•Magnitude limit:18-19(within 1-3 min image acq.)

ROTSE: 4 robotic telescopes:

•Diameter: 45 cm•Field of view: 1.85°×1.85°•Magnitude limit: ~19 for 1 minute

exposure

27 alerts sent in 2 years (2009-2010)17 followed

9 not followed1 cancelled

Image to analyzeReference Image Subtraction

Image analysisunder development

Supra-luminal neutrinos•Cohen-Glashow idea:In case of Lorentz invariance violation, some processes are kinematically allowed (A. Cohen, S. Glashow, New Constraints on Neutrino Velocities, arXiv:1109.6562v1)

•Test: take the highest energy events and put limits on dOPERA : d10-5

Supra-luminal neutrinos

The mesurement:•Assume neutrino production in the atmosphere, •look for most enegetic upgoing muons,•take the muon energy as the neutrino threshold energy Ethr•take the distance L as the neutrino path in the Earth ,

The data:Maximum estimated energy 40 TeVL=cosq x DEarth=5340 KmResults in d 4 10-11

Considering energy reconstruction uncertainty,a conservative upper limit is set to

d≥ 1.7 x10-10

… and more• Nuclearites & monupoles Close to unblinding 2007-2008 data. Good prospects for limits.

•Neutrinos from galactic planeWill start soon

•Indirect dark matter searchesAnalysis from the Sun started

•CR compositionHit clustering algorithm selection in progress

• Supernova detectionTough due to bioluminescence. But double and triple coincidence method have sensitivity up to 4-5 kpc provided background rate is low

• Detection of HE γ-raysIn progress.•Cosmic rays anisotropiesJust started

… not only neutrino detection•The 13th line is used for the calibration of the neutrino telescope but also contains several instruments dedicated to marine and Earth sciences and to acoustic detection

•This facility allows the continuous monitoring of the most important characteristics of the sea water at the site of the detector

•The data are essential for a comparison to the models which describe the deep sea waters behaviour in the Mediterranean and to the R&D for future neutrino acoustic detection

CONCLUSIONSANTARES today:

• Successful end of construction phase• Technology proven• Data taking ongoing

First physics outputs: set limits on • Point like neutrino sources, • Diffuse neutrino flux

…..On the road for the next step:

a detector at the km3 scale in theMediterranean sea

Analysis in pogess on: • Neutrino flux from FB• Coincidences with GRB and high energy

flares• Neutrino oscillations, magnetic

monopoles, • Indirect dark matter search• etc.