Update on discovery potential for point-like sources A. Trovato, R. Coniglione and P. Sapienza KM3NeT General Meeting, LNS Catania, 20-23 February 2012

Overview Update on the reconstruction code exploiting the multi- PMT peculiarities and the source direction Results for different detector configurations Discovery potential for the RXJ1713.7-3946 considering different source morphologies Preliminary results on discovery potential for the source RXJ0852.0-4622 (Vela Jr) Trovato Agata - KM3NeT General Meeting, LNS Catania, 20-23 February 2012

Simulation Codes from Antares Waters & PMT characteristics from WPD document Package Version Io v1r12 Antcc v3r7 Gendet v1r3 Genhen v6r6 Km3 Modk40 v4r10 Reco See Next Slides Detector 2 blocks of 154 DUs(towers) 20 storey (40 m spacing)/DU 2 multi-PMT/storey Trovato Agata - KM3NeT General Meeting, LNS Catania, 20-23 February 2012

Reconstruction code Original “AartStrategy” reconstruction algorithm modified to exploit the multi-PMT peculiarities Trigger based on coincidence between PMT on the same OM (L1). First study on coincidence between OM on the same floor (1T1) Dependence on the hit amplitude neglected Angular Selection: hit accepted in a given PMT field of view (cosθ< −0.5, whereθis the angle between the incident photon from a starting track and the axis of the PMT) during the hit selection and in the Pdfs Adopt “multi-PMT” as optical module require to modify the original “AartStrategy” reconstruction algorithm exploiting the multi-PMT peculiarities track photon -θ PMT axis Trovato Agata - KM3NeT General Meeting, LNS Catania, 20-23 February 2012

Reconstruction scheme Linear prefit All hits Angular Selection Selected hits Prefit hits Linear prefit Merged hits Generate start tracks For each track: Angular Selection + Time Residual M-estimator fit M-estim. hits Pdf fit pdf hits Angular Selection + Time Residual Best track Angular Selection + Time Residual Final fit Final pdf hits Trovato Agata - KM3NeT General Meeting, LNS Catania, 20-23 February 2012

Source Direction as Prefit Many TeV gamma-ray sources have been recently identified and some of them are expected to be also high energy neutrinos sources For neutrinos coming from a specific source, we can use its direction in the fit procedure: Prefit directions = neutrino direction±2° Prefit vertex obtained using the method of Lagrange multipliers to find the minimum of the χ2 in the linear fit Hit selection: Hits accepted within a cylinder of 150 m radius having the prefit track as axis The choice of a good starting track is fundamental to obtain an accurate estimate of the neutrino track This procedure can be extended to the all sky searches with a sky scanning Trovato Agata - KM3NeT General Meeting, LNS Catania, 20-23 February 2012

Search for point-like sources Binned method Trigger: both 5L1 and 1T1 have been considered. The best results are showed. Discovery potential minimized on: ∧=logL/NDOF (goodness of fit criterion) Nhit: number of hits used to reconstruct the event Rbin: angular radius of the search cone centred on the source (angular fit error) Trovato Agata - KM3NeT General Meeting, LNS Catania, 20-23 February 2012

RXJ1713.7-3946 – part 1 Source simulated as a neutrino emitting homogeneous disk of 0.6° radius Neutrino Energy Spectrum: HESS data Trovato Agata - KM3NeT General Meeting, LNS Catania, 20-23 February 2012

RXJ1713.7-3946 – part 1 Source simulated as a neutrino emitting homogeneous disk of 0.6° radius Neutrino Energy Spectrum: Number of years required for a 5σ and 3σ discovery of the RXJ1713.7-3946 source evaluated for different detector configuration Error on the number of years roughly estimated only from the Monte-Carlo background statistics What about the systematic errors? Trovato Agata - KM3NeT General Meeting, LNS Catania, 20-23 February 2012

~0.25 y ~0.55 y ~0.5 y Errors estimate From error propagation on the Monte-Carlo background statistics Steep curve Flat curve From the propagation of error we obtain a 3% of erro in the flux Trovato Agata - KM3NeT General Meeting, LNS Catania, 20-23 February 2012

RXJ1713.7-3946 vs DU distance Performance improves decreasing DU distance Trovato Agata - KM3NeT General Meeting, LNS Catania, 20-23 February 2012

RXJ1713.7-3946 vs bar length Performance improves increasing bar length Trovato Agata - KM3NeT General Meeting, LNS Catania, 20-23 February 2012

RXJ1713.7-3946 morphology Simulation performed with a 0.6 flat disk that is a very rough and conservative assumption Indeed RXJ1713.7-3946 exhibit a rather complex morphology First attempt for more realistic simulations with hot spots and radial profile are shown Trovato Agata - KM3NeT General Meeting, LNS Catania, 20-23 February 2012

RXJ1713.7-3946 hot spots RXJ1713.7-3946 is a TeVγ-ray supernova remnant emitting synchrotron X rays. Observations indicate the existence of dense molecular clouds inside the shell of RXJ1713.7-3946 (Sano H. et al., 2010, arXiv:1005.3409) in correspondence of high intensity gamma emission zones The associations between SNR and molecular clouds provide the optimal conditions to produce intense neutrino fluxes (Vissani F. et al., 2011, arXiv:1101.4842) Molecular clouds are spatially correlated with gamma-ray distribution that thereby can be used as a tool to test the hypothesis that supernova remnants (SNR) are main sites of the acceleration of the galactic cosmic rays Trovato Agata - KM3NeT General Meeting, LNS Catania, 20-23 February 2012

RXJ1713.7-3946 hot spots Intensity distribution of the 12CO(J=2-1) transition DEC L G C A The more luminous and massive CO peaks are: RA Equipped with a 4 m submillimeter telescope, NANTEN2 will be used to survey the southern sky in molecular and atomic spectral lines between 110 and 880 GHz (2.6 mm to 350 micron wave length) It looks for molecular and atomic carbon lines CO=monossido di carbonio=carbon monxide Name RA (°) DEC (°) A 257.90 -39.98 C 258.11 -39.93 G 257.73 -39.76 L -39.48 Position of the CO peaks on the HESS gamma-ray excess images from 2005 data Trovato Agata - KM3NeT General Meeting, LNS Catania, 20-23 February 2012

RXJ1713.7-3946 hot spots Assuming that the SNR flux is emitted by these four spots simulated as point-like (each one emitting ¼ of the total flux) the results obtained are: Flux perc. 5σ disc. years 100%(1.68e-14) 3.6±0.2 90%(1.51e-14) 4.2±0.3 80%(1.34e-14) 5±0.4 Equipped with a 4 m submillimeter telescope, NANTEN2 will be used to survey the southern sky in molecular and atomic spectral lines between 110 and 880 GHz (2.6 mm to 350 micron wave length) It looks for molecular and atomic carbon lines CO=monossido di carbonio=carbon monxide Percentage of the total RXJ1713.7-3946 emitted by the 4 hot spot Detector with a tower distance of 130 m and bar length of 6 m Trovato Agata - KM3NeT General Meeting, LNS Catania, 20-23 February 2012

RXJ1713.7-3946 radial profile HESS gamma-ray radial profiles around the centre of the SNR. Excess events per unit solid angle as a function of the distance r to the SNR centre. A&A 464, 235-243 (2007) Molecular clouds are spatially correlated with gamma-ray distribution that thereby can be used as a tool to test the hypothesis that supernova remnants (SNR) are main sites of the acceleration of the galactic cosmic rays Taking into account this radial profile in the event weights, the number of years required for the 5σ discovery is 6.5±0.4 (PRELIMINARY) Trovato Agata - KM3NeT General Meeting, LNS Catania, 20-23 February 2012

Strong morphology dependence RXJ1713.7-3946 morphology For a detector with a tower distance of 130 m and bar length of 6 m: Method Years for 5σ discovery Homogeneous disk r=0.6° 7.2±0.4 4 Hot Spot (80% flux) 5±0.4 Radial Profile 6.5±0.4 Strong morphology dependence Trovato Agata - KM3NeT General Meeting, LNS Catania, 20-23 February 2012

RXJ0852.0-4622 (Vela Jr) Source simulated as a neutrino emitting homogeneous disk of 0.9° radius Same Energy Spectrum as RXJ1713.7-3946 but with the intensity I0=2.1×10-14 HESS data Astr.Ph. J., 661:236-249 (2007) Years for 5σ discovery = 7±0.3 (detector with 6m bar length and 130m tower distance) Neutrino Flux used Trovato Agata - KM3NeT General Meeting, LNS Catania, 20-23 February 2012

Work in progress Search with unbinned method applied on track reconstructed with directional information Continue to study RXJ1713.7-4946 and other galactic and extra-galactic potential neutrino sources Trovato Agata - KM3NeT General Meeting, LNS Catania, 20-23 February 2012