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Results from 2007-08 data unblinding on point source analysis with the EM algorithm

AWG videoconference meeting 24/03/2011 (II). Results from 2007-08 data unblinding on point source analysis with the EM algorithm. J.P Gómez-González AWG videoconference meet. 24/03/2011. Outline. Search method review Results from the candidate list search

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Results from 2007-08 data unblinding on point source analysis with the EM algorithm

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  1. AWG videoconference meeting 24/03/2011 (II) Results from 2007-08 data unblinding on point source analysis with the EM algorithm J.P Gómez-González AWG videoconference meet. 24/03/2011

  2. Outline • Search method review • Results from the candidate list search • Results for the all sky search • Summary J.P Gómez-González AWG videoconference meet. 24/03/2011

  3. Clustering algorithm EM free likelihood distribution example The EM algorithm is a clustering algorithm that analytically maximizes the likelihood We assume that source events follow a Gaussian distribution The width of this Gaussian includes the dependence of on the angular resolution of the detector: In the “free sigma case” the width can change during the maximization process between reasonable values. Remind that both sigmas are keep as independent parameters. In the “fixed sigma case” the width do not change and keeps the value extracted from the mc simulations J.P Gómez-González AWG videoconference meet. 24/03/2011

  4. Data sample Reconstruction method: aafit v0r8 Same events coordinates (checked) ~304 days of livetime 2190 events in the sample Cuts:  > -5.4,  < 1º, upgoing events J.P Gómez-González AWG videoconference meet. 24/03/2011

  5. Sky map Sky map in equatorial coordinates showing the positions of the 2190 events used in the analysis J.P Gómez-González AWG videoconference meet. 24/03/2011

  6. EM free candidate list search pre-trial J.P Gómez-González AWG videoconference meet. 24/03/2011

  7. EM fix candidate list search pre-trial J.P Gómez-González AWG videoconference meet. 24/03/2011

  8. NIKHEF PS analysis results J.P Gómez-González AWG videoconference meet. 24/03/2011

  9. Summary of results The most significant sources on the candidate list are found by all the “different” methods (compatible results in all cases) J.P Gómez-González AWG videoconference meet. 24/03/2011

  10. Clusters from candidate list search EM free The gaussian is wider in the RA plane. Sigma parameters (X,Y) are independent HESS J1023-575 Number of events fitted by the algorithm: 3.32 Likelihood ratio value: 4.32 P-value: 0.0074 x 24 ~ 17.8% probability (< 1.5) Gaussian width: sx = 1.10º , sy = 0.5º Green ellipse: pre-clustering cone Blue ellipse: fitted gaussian J.P Gómez-González AWG videoconference meet. 24/03/2011

  11. Clusters from candidate list search EM fix Now, the sigma values of the Gaussian are fixed HESS J1023-575 Number of events fitted by the algorithm: 2.53 Likelihood ratio values: 3.25 P-value: 0.0036 x 24 ~ 8.7 % probability Same cluster was found in the 5line analysis, but now we have only one event from that period event id: 1 -- decl: -57.839516 -- ar: 157.401820 -- nhit: 52 -- nline: 4 -- run: 27892 event id: 2 -- decl: -57.641273 -- ar: 154.210445 -- nhit: 39 -- nline: 8 -- run: 32490 event id: 3 -- decl: -57.742114 -- ar: 159.541817 -- nhit: 25 -- nline: 5 -- run: 33486 event id: 4 -- decl: -57.535276 -- ar: 156.459877 -- nhit: 70 -- nline: 6 -- run: 33713 Green ellipse: pre-clustering cone Blue ellipse: fitted gaussian J.P Gómez-González AWG videoconference meet. 24/03/2011

  12. Clusters from candidate list search EM free GX 339 Number of events fitted by the algorithm: 4.77 Likelihood ratio value: 2.53 Green ellipse: pre-clustering cone Blue ellipse: fitted gaussian J.P Gómez-González AWG videoconference meet. 24/03/2011

  13. Clusters from all sky search EM free clust 2 clust 1 P > 95% (BG) Same cluster found in the NIKHEF analysis J.P Gómez-González AWG videoconference meet. 24/03/2011

  14. Clusters from all sky search EM fix Same cluster found by NIKHEF analysis event id: 0 -- decl: -0.569987 -- ar: 43.104131 -- nhit: 50 -- nline: 6 -- run: 36133 event id: 1 -- decl: -0.566569 -- ar: 42.962954 -- nhit: 42 -- nline: 8 -- run: 37151 event id: 2 -- decl: -0.348181 -- ar: 43.711867 -- nhit: 49 -- nline: 6 -- run: 34397 event id: 3 -- decl: -2.853588 -- ar: 42.782587 -- nhit: 24 -- nline: 3 -- run: 30437 Green ellipse: pre-clustering cone Blue ellipse: fitted gaussian J.P Gómez-González AWG videoconference meet. 24/03/2011

  15. Summary • Sample from 2007-08 data unblinded • Similar results than previous analysis were found • Candidate list: HESS J1023-575  p ~ 17.8% • All sky: fully compatible with BG hypothesis J.P Gómez-González AWG videoconference meet. 24/03/2011

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