Results from 2007-08 data unblinding on point source analysis with the EM algorithm
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Results from 2007-08 Results from 2007-08 data unblinding on data unblinding on point source analysis point source analysis with the EM algorithm with the EM algorithm AWG AWG videoconference videoconference meeting meeting 24/03/2011 24/03/2011 (II) (II) J.P Gómez-González AWG videoconference meet. 24/03/2011 0
description
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 - PowerPoint PPT Presentation
Transcript of Results from 2007-08 data unblinding on point source analysis with the EM algorithm
Results from 2007-08 Results from 2007-08 data unblinding on point data unblinding on point source analysis with the source analysis with the
EM algorithmEM algorithm
AWG AWG videoconference videoconference
meetingmeeting24/03/201124/03/2011
(II)(II)
J.P Gómez-González AWG videoconference meet. 24/03/2011 0
Search method review
Results from the candidate list search
Results for the all sky search
Summary
OutlineOutline
J.P Gómez-González AWG videoconference meet. 24/03/2011 1
Clustering algorithm
EM free likelihood distribution exampleThe 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 2
Data sample
J.P Gómez-González AWG videoconference meet. 24/03/2011
Same events coordinates (checked)~304 days of livetime
2190 events in the sample
Cuts: > -5.4, < 1º, upgoing events
Reconstruction method: aafit v0r8
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Sky map
J.P Gómez-González AWG videoconference meet. 24/03/2011
Sky map in equatorial coordinates showing the positions of the 2190 events used in the analysis
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EM free candidate list search
J.P Gómez-González AWG videoconference meet. 24/03/2011
pre-trial
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EM fix candidate list search
J.P Gómez-González AWG videoconference meet. 24/03/2011
pre-trial
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NIKHEF PS analysis results
J.P Gómez-González AWG videoconference meet. 24/03/2011 7
Summary of results
J.P Gómez-González AWG videoconference meet. 24/03/2011
method source decl ra nsig lik p-value
EM free HESS J1023-575
-57.76 155.83 3.32 4.32 0.18
EM free GX 339 -104.3 -48.79 4.77 2.53 0.10
EM fix HESS J1023-575
-57.76 155.83 2.53 3.25 0.09
EM fix GX 339 -104.3 -48.79 1.77 2.46 0.25
Lik (NIKHEF)
HESS J1023-575
-57.76 155.83 2.65 2.53 0.17
Lik (NIKHEF)
GX 339 -104.3 -48.79 2.18 2.15 0.26
The most significant sources on the candidate list are found by all the “different” methods (compatible results in all cases)
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Clusters from candidate list search
Number of events fitted by the algorithm: 3.32Likelihood ratio value: 4.32P-value: 0.0074 x 24 ~ 17.8% probability (< 1.5)Gaussian width: sx = 1.10º , sy = 0.5º
The gaussian is wider in the RA plane. Sigma parameters (X,Y) are
independent
EM free
HESS J1023-575HESS J1023-575
J.P Gómez-González AWG videoconference meet. 24/03/2011
Green ellipse: pre-clustering coneBlue ellipse: fitted gaussian
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Clusters from candidate list search
Number of events fitted by the algorithm: 2.53Likelihood ratio values: 3.25P-value: 0.0036 x 24 ~ 8.7 % probability
Now, the sigma values of the Gaussian are fixed
EM fix
HESS J1023-575HESS J1023-575
J.P Gómez-González AWG videoconference meet. 24/03/2011
Green ellipse: pre-clustering coneBlue ellipse: fitted gaussian
event id: 1 -- decl: -57.839516 -- ar: 157.401820 -- nhit: 52 -- nline: 4 -- run: 27892event id: 2 -- decl: -57.641273 -- ar: 154.210445 -- nhit: 39 -- nline: 8 -- run: 32490event id: 3 -- decl: -57.742114 -- ar: 159.541817 -- nhit: 25 -- nline: 5 -- run: 33486event id: 4 -- decl: -57.535276 -- ar: 156.459877 -- nhit: 70 -- nline: 6 -- run: 33713
Same cluster was found in the 5line analysis, but now we have only one event from that period
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Clusters from candidate list search
Number of events fitted by the algorithm: 4.77Likelihood ratio value: 2.53
EM free
GX 339GX 339
J.P Gómez-González AWG videoconference meet. 24/03/2011
Green ellipse: pre-clustering coneBlue ellipse: fitted gaussian
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Clusters from all sky search
EM free
J.P Gómez-González AWG videoconference meet. 24/03/2011
clust decl ra bic nsig
1 -36.71 39.92 7.9 2.89
2 -0.50 43.26 7.1 2.89
clust 1clust 2
Same cluster found in the NIKHEF analysis
P > 95% (BG)
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Clusters from all sky search
EM fix
J.P Gómez-González AWG videoconference meet. 24/03/2011
Green ellipse: pre-clustering coneBlue ellipse: fitted gaussian
decl ra bic nsig
-0.50 43.28 7.1 2.89
Same cluster found by NIKHEF analysis
event id: 0 -- decl: -0.569987 -- ar: 43.104131 -- nhit: 50 -- nline: 6 -- run: 36133event id: 1 -- decl: -0.566569 -- ar: 42.962954 -- nhit: 42 -- nline: 8 -- run: 37151event id: 2 -- decl: -0.348181 -- ar: 43.711867 -- nhit: 49 -- nline: 6 -- run: 34397event id: 3 -- decl: -2.853588 -- ar: 42.782587 -- nhit: 24 -- nline: 3 -- run: 30437
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J.P Gómez-González AWG videoconference meet. 24/03/2011
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
SummarySummary
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