Neutrino telescopes in the Mediterranean sea

1. Neutrino telescopes in the Mediterranean sea • The ANTARES detector • Results and physicsanalisys in ANTARES • Marco Anghinolfi • INFN-Genova • on behalf of the ANTARES Collaboration • HEP2012 • Vlaparaiso, January 2012

2. The goals Extra-Galactic Galactic GRB Supernova remnants e+ ge +gHE(inverse Compton) p/A +p/g p0 + p + ...  gHEgHEnmm  nm nee Pulsars Microquasars AGN • Origin of cosmic rays • Understanding of know sources • Unknown phenomena Th. Stolarczyk - CEA Irfu

3. Detection Principle Neutrinos (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.

4. p,  107 atm. per year  ~103 atm.  p   cosm.  Signal to noise

5. The sky coverage of ANTARES • 42°50’ North • 6°10’ East • 2500 m depth

6. The ANTARES detector

7. How does a muon look like? A typical up-going event

8. EnvironmentalBackground

9. Reconstructed up-going events/day full 12 line connection Periodwithhigh bioluminescence single line multi line Neutrinos (multi-line, single-line) per day

10. Comparison to Monte Carlo 5-line data (May-Dec. 2007)+ 9-12 line data (2008) reconstruction BBfit v3r2, single- and multi-line fit down-going up-going 1062  cand. elevation angle  good agreement with Monte Carlo: atmospheric neutrinos: 916 (30% syst. error) atmospheric muons: 40 (50% syst. error)

11. Search for point-like n sources Badly reconstructed Well reconstructed data set: 2007-2008 data taken with 5, 9, 10, and 12 operating detector lines uncertainties in angle reconstruction: median: 0.5O 12-line data: 0.4O absolute orientation: 0.1O

12. Full-sky search Sky map in Galactic Coordinates Background colour indicates visibility Blue points: 3058 selected events Red stars: candidate source list Most significant cluster at: RA= ‒46.5°, δ= ‒65.0° Nsig = 5 Q = 13.02 p-value = 0.026 Significance = 2.2 σ Result compatible with the background hypothesis

13. 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 very high energy component (E >1 PeV) for Southern Sky).

14. 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 • Highenergymuons can produce more thanone hit in thesame PMT M. Vecchi

15. Results on diffuse cosmic  flux

16. On-going Physics analyses n flux from Fermi bubbles

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

18. Fermi bubbles • If the hadronic scenario is confirmed FB • are 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: expected • flux limits soon

19. 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

20. Searches for Neutrinos from GRB • Search for muons produced by neutrinos in correlation with gamma-ray : • candidate tracks are required to point back to • the 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

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 blazar 3C454.3 measured by Fermi above 100 MeV for almost 2 years of data

22. 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/space • coincidence with the gamma-ray emission from the flare 3C279 • p-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 a • promisingsearch of neutrinos Gamma-ray light curve of the blazar 3C279. The red bar is the time of the ANTARES neutrino event

23. ANTARES & AUGER • ultra high energy cosmic rays are expected to be accompanied • by gamma-rays and neutrinos from pion decays • field of view for the ANTARES telescope and • the Pierre Auger Observatory • (PAO) greatly overlap. • correlation of arrival directions • of 2190 neutrino candidate events detected by 5-12 • line ANTARES neutrino telescope, and 69 UHECRs observed • by the PAO

24. ANTARES & AUGER 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 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

25. Multi-Messenger astronomy Strategy:higherdiscoverypotentialby observingdifferentprobes Highersignificanceby coincidencedetection Higherefficiencyby relaxedcuts MoUs for joint research Alerts TAROT optical follow up: 10 s repositioning Ligo/Virgo Gravitationalwaves: trigger + dedicated analysischain GCN GRB Coord. Network: γ satellites

26. An exemple: opticalfollow-up • Alerts sent by ANTARES • High energy  (nhits& amp) • expected ~ 2/month • 27 alerts sent in 2 years (2009-2010) • 17 followed • 9 not followed • 1 cancelled • 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 Image analysis under development Image to analyze Reference Image Subtraction

27. 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 d • OPERA : d10-5

28. Supra-luminal neutrinos • Themesurement: • Assume neutrino production in theatmosphere, • look formostenegeticupgoingmuons, • takethe muon energy as the neutrino thresholdenergyEthr • takethedistance L as the neutrino path in theEarth , • The data: • Maximumestimatedenergy 40 TeV • L=cosq x DEarth=5340 Km • Results in d 4 10-11 • Consideringenergyreconstructionuncertainty, • a conservativeupperlimitis set to • d≥ 1.7 x10-10

29. … and more • Nuclearites & monupoles • Close to unblinding 2007-2008 data. Good prospects for limits. • Neutrinos from galactic plane • Will start soon • Indirect dark matter searches • Analysis from the Sun started • CR composition • Hit clustering algorithm selection in progress • Supernova detection • Tough 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-rays • In progress • . • Cosmic rays anisotropies • Just started

30. … 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

31. CONCLUSIONS • ANTARES today: • Successful end of construction phase • Technology proven • Data taking ongoing • First physics outputs: set limits on • Point like neutrino sources, • Diffuse neutrino flux • Analysis in pogess on: • Neutrino flux from FB • Coincidences with GRB and high energy flares • Neutrino oscillations, magnetic monopoles, • Indirect dark matter search • etc. • …..On the road for the next step: • a detector at the km3 scale in the • Mediterranean sea