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Time variable analysis

Time variable analysis. AWG videoconf – November 4 th 2010. A bit of history : 4 presentations during last collaboration meetings : - CERN ( fev 2010): description of the method - Clermont ( may 2010): + results with BBFit

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Time variable analysis

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  1. Time variable analysis AWG videoconf – November 4th 2010

  2. A bit of history: 4 presentationsduringlastcollaborationmeetings: - CERN (fev 2010): description of themethod - Clermont (may 2010): + resultswithBBFit - Paris (sept 2010)+MANTS: + resultswithAAFit Contents: - Introduction * Motivation * Likelihoodmethod - AnalysiswithBBFit and AAFit * Data/MC comparison * Performances of thealgorithm ( fixedsource) * Candidatesourcessearch * Systematicerrors - Summary and perspectives

  3. Introduction: motivation More than 50% of sources are foundtobe variable… → Use this time informationdireclty in theanalysis: * reduce effectivelythebackground * improvethediscoverypotentialovera time integratedsearch. → Searchforsignalfromblazars AGN – candidatesourcesfor UHECR (p-γor p-p  strongcorrelationbetweenγ-rayand neutrino fluxes) • γ-ray catalogues: • Fermi (>100 Mev - ~10 GeV) • IACT (>100 GeV)

  4. Introduction: Likelihoodmethod Method: unbinnedsearchusing a likelihood ratio (Garo’smethod) Noise: Signal: Only up-goingmultilineevents (2008 data ~57 days) Optimizationin ordertofindthemimimum neutrino flux tohave a 3 (5)sigma discovery

  5. Unbinnedanalysis: 1) data Time distribution of theupgoingmulti-line eventsreconstructedwithBBFit and selectwith tchi2<1.8

  6. Unbinnedanalysis: 1) data Time distribution of theupgoingmulti-line eventsreconstructedwithBBFit and selectwith tchi2<4 1st approx: flat distribution. Next: use direcltythiskind of distributionwithveryloosecut as the time PDF forbackground

  7. Unbinnedanalysis: 2) data/MC comparison AAFit BBFit Reconstruction: AAFit v0r6 (+Antdst) Reconstruction: BBFit v3r6 • MC productions: • Add 2ns hit smearing • 12L 3pe + 10pe periods • Neutrino+antineutrino: Bartol flux • Muons: corsika + bugaevnormalisation + scale *2 • MC productions: • Add 2ns hit smearing + 0.5ns interline (cfNickef’s PS) + noiseextractedfromsummaryfilefromall 2008 L12 data. • Neutrino+antineutrino: Bartol flux • Muons: mupage (~13.9days) • Data: interline offset (cfNickef’s PS) Legend: data: blackdots MC un+anu: blue line MC muons: red line MC all: green line

  8. Unbinnedanalysis: 2) data/MC comparison AAFit BBFit Upgoingeventswith error estimateβ<1º Upgoingeventswithnline>1 && nhit>5

  9. Unbinnedanalysis: 2) data/MC comparison AAFit BBFit Alleventswithβ<1º && Λ>-5.4 Alleventswithnline>1 && nhit>5 && tchi2<1.5

  10. Unbinnedanalysis: 2) data/MC comparison AAFit BBFit Upgoingeventswith error estimateβ<1º && Λ>-5.4 Upgoingeventswithnline>1 && nhit>5 && tchi2<1.5

  11. Unbinnedanalysis: 2) data: number of events AAFit BBFit Upgoingeventswith error estimateβ<1º Upgoingeventswithnline>1 && nhit>5

  12. Unbinnedanalysis: 3) performances AAFit BBFit Upgoingeventswithnline>1 && nhit>5 && tchi2<1.2, 1.4, 1.6…, 3.0 Upgoingeventswithβ<1º && Λ>-4.8, -4.9, -5.0,…-5.8

  13. Unbinnedanalysis: 3) performances AAFit BBFit Upgoingeventswithnline>1 && nhit>5 && tchi2<1.2, 1.4, 1.6…, 3.0 && tcosth>0.17 Upgoingeventswithβ<1º && Λ>-4.8, -4.9, -5.0,…-5.8 (Integration E-2spectrumfrom 10GeV-10PeV)

  14. Unbinnedanalysis: 3) performances Unbinnedanalysis: comparisonAAFit / BBFit AAFit BBFit Upgoingeventswithnline>1 && nhit>5 && tchi2<1.5, 1.8, 2.0 Upgoingeventswithβ<1º && Λ>-5.0, -5.4, -5.8

  15. Unbinnedanalysis: 3) performances δ=-40º AAFit BBFit Upgoingeventswithnline>1 && nhit>5 && tchi2<1.2, 1.4, 1.6…, 3.0 Upgoingeventswithβ<1º && Λ>-4.8, -4.9, -5.0,…-5.8

  16. UnbinnedanalysiswithAAFit and BBFit: • Twomainsteps: • 1) Determination of the performances of theunbinnedmethodalgorithm: • Generation of theevents in one single sourcewithone single flare [squareshape] with a variable widthfrom 0.1day to 84days and withoutusingthetiminginformation. • 2) Candidatesourcessearch: •  Use the full time PDF of thesourceextractedfromthe gamma ray light curve.

  17. UnbinnedanalysiswithAAFit: fixedsearch Yellow: bkg Red: bkg+1 event Green: bkg+3 events Blue: bkg+5 events Pink: bkg+7 events Light blue:bkg+9 events

  18. UnbinnedanalysiswithAAFit: fixedsearch Zeroproblem:  Difficultcomputation of thesensitivityespeciallyforvery short flare comes fromthefactthattheprobabilitytohaveexactly 0 eventsaroundonesource at lessthanfewdegresincreases (lessproblematicforBBFit)  Stability of thefit in ordertofindthecutfor 5s • Solutions: • Extendtheradius of thesimulation of thebackground: 3º->20º • Add a smallrandomnumbertothelikelihood ratio: Uniform(10-5) • Increasethestatisticforthe PE generation105 -> 107(especiallyforveryrestrictive lambda value)

  19. UnbinnedanalysiswithAAFit: fixedsearch

  20. UnbinnedanalysiswithAAFit: fixedsearch Stability of thefit 35σ 1day 84 days 3 days No timing 0.1 day No timing

  21. UnbinnedanalysiswithAAFit: fixedsearch Number of eventsneededfor a 3σdiscovery FordifferentcutonΛvalue: >-4.8, -4.9, -5.0…-5.8 ConversionNevent Flux withthevisibility, effectivearea and live time

  22. UnbinnedanalysiswithAAFit: fixedsearch No timing

  23. UnbinnedanalysiswithAAFit: fixedsearch No timing 25 days 5σ 3σ 10 days 1 day

  24. UnbinnedanalysiswithAAFit: fixedsearch Declination : -40º

  25. UnbinnedanalysiswithAAFit: fixedsearch Declination : -40º

  26. UnbinnedanalysiswithAAFit: candidatesource Fermi Sources: July – December 2008 → Selection of Blazars → Flux (>300MeV) > 20 10-8 photons.cm-2.s-1 (highstate) → Variabilityσ2NXS > 0.15 (Abdo et al, ……..) Selection

  27. UnbinnedanalysiswithAAFit: candidatesource Fermi gamma-ray light curve for 3C454.3 Time PDF (beforenormalisation) (Flare’sdetermination: cftalk at Paris)

  28. UnbinnedanalysiswithAAFit: candidatesource

  29. UnbinnedanalysiswithAAFit: Expectedresultsforthesensitivity (90% CL) and forthe 3(5) σdiscoverypotential (50% prob) Flux: GeV.m-2.s-1

  30. UnbinnedanalysiswithAAFit: Expectedresultsforthesensitivity (90% CL) and forthe 3(5) σdiscoverypotential (50% prob)

  31. UnbinnedanalysiswithAAFit: • 2 sources of systematicerrors: • Angular resolution: makeworsethe angular resolutionby a factor 15% appliedwitha gaussiandistribution (cfAartpointsource ) • Keepthesame PDF butchangeonlythe PSF forthegeneration • Efficiency: makeworsetheefficiencyby a factor 30% • changethenumber of eventsinjected in thesample (gauss(1,0.3)) • - Extrapolation 3->5σ ? • - Otherssources: absolutepointing, …

  32. UnbinnedanalysiswithAAFit: Expectedresultsforthesensitivity (90% CL) and forthe 3(5) σdiscoverypotential (50% prob) includingthesystematicerrors Averageeffect: Sensititivty: ~1.10 Discovery: ~1.20

  33. UnbinnedanalysiswithBBFit: fixedsource

  34. UnbinnedanalysiswithBBFit: fixedsource Declination : -40º No timing 10days 0.1day 1day

  35. UnbinnedanalysiswithBBFit: fixedsource Declination : -40º

  36. UnbinnedanalysiswithBBFit: fixedsource Declination : -40º

  37. UnbinnedanalysiswithBBFit: candidatesource Source 3C454.3

  38. UnbinnedanalysiswithBBFit: candidatesource Expectedresultsforthesensitivity (90% CL) and forthe 3(5) σdiscoverypotential (50% prob) Flux: GeV.m-2.s-1 1.8: 451 bkgevents 2.4: 2748 bkgevents 2.0: 791 bkgevents 3.0: 8702 bkgevents

  39. UnbinnedanalysiswithBBFit: candidatesource Expectedresultsforthesensitivity (90% CL) and forthe 3(5) σdiscoverypotential (50% prob)

  40. UnbinnedanalysiswithBBFit: candidatesource Expectedresultsforthesensitivity (90% CL) and forthe 3(5) σdiscoverypotential (50% prob) includingthesystematicerrors. Samesource of systematicerrorsthantheonesusedwithAAFit: - Ang Res: +gauss(1,0.15) - Efficiency: +gauss(1,0.3) ontheinjectednumber of signalevents Averageeffect: Sensititivty: ~1.20 Discovery: ~1.15

  41. Unbinnedanalysis: comparisonAAFit / BBFit

  42. Unbinnedanalysis: comparisonAAFit / BBFit

  43. Summary and perspectives: Unbinnedanalysis of the Fermi sources in 2008 (~57 days) is (almost) done. Internalclosetobefinished Perspectives: 1) Use the time distribution of the data in ordertosimulatebackgroundeventsand tobuildthe time PDF. Example: alleventsreconstructedwiththe on-line BBFitwith at least 2 lines and a fitquality, tchi2<4.0

  44. Summary and perspectives: Time variable analysisseemstoworkedusingBBFitorAAFitwiththe12L data in 2008 Perspectives: 2) Extendtheanalysisto 2009-10 data Missing: Data: BBFit-> OK Data: interline offset ? MC: on-going, help ? Source 3C454.3 gamma-ray light curve fromAug 2008 toSept 2010

  45. Summary and perspectives: Time variable analysisseemstoworkedusingBBFitorAAFitwiththe12L data in 2008 Perspectives: 2) Extendtheanalysisto 2009-10 data Missing: Data: BBFit-> OK Data: interline offset ? MC: on-going, help ? Time distribution of the data for 2008-09-10 reconstructedwithBBFit (tcosth>0&&tchi2<1.8&&nline>1&&nhit>5)

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