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Data Analysis Markarian 421 – 14.-15.02.2004 Crab Nebula – 27.01.2004 Crab Nebula – 15.02.2004  2 dim plots : false source analysis  Miss-pointing study.

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Presentation on theme: "Data Analysis Markarian 421 – 14.-15.02.2004 Crab Nebula – 27.01.2004 Crab Nebula – 15.02.2004  2 dim plots : false source analysis  Miss-pointing study."— Presentation transcript:

1 Data Analysis Markarian 421 – 14.-15.02.2004 Crab Nebula – 27.01.2004 Crab Nebula – 15.02.2004  2 dim plots : false source analysis  Miss-pointing study  Light Curves Data:

2 Applied Cuts (David’s Talk) 0.12 < LENGTH < 0.32 0.06 < WIDTH < 0.15 0.6 < DIST < 1.3 SIZE > 3000 ( photons) Calculate significance: Li&Ma (1983) formula #17 ALPHA(max) = 10 degrees

3 False source analysis Calculate once source independent parameters: LENGTH, WIDTH, SIZE, etc For each assumed source position calculate source dependent parameters: DIST, ALPHA The movement of the sky (derotation) The same procedure for ON and OFF

4 2 dim sky plot Camera coordinatesSky coordinates

5 2 dim sky plot (N ex) Camera coordinates Sky coordinates

6 Why is the spot not very narrow? Center of the camera is not the center of the rotation? Divide the ON sample in several sub-samples No derotation Use the whole OFF sample to calculate significance

7 Tracking / Miss-pointing

8 Estimation of the source position in each of the sub-samples Several criteria: Significance Number of excess events Alpha plot: signal and background shape Alpha plots of the nearby positions

9 Estimated source positions

10 First light curve Markarian 421

11 Fine binning: 25 samples Normal spotAbnormal spot (1 run)

12 Closer look to this sub-sample 2 minutes, 1 Run, no reports in the runbook First 5633 eventsLast 5633 events

13 Following the miss-pointing

14 Mrk421: 2 nd ON sample Derotation around the center of the camera Displacement from the center of around 0.3 deg Roundish spot

15 Second light curve

16 Zenith and azimuth angle

17 Crab: 27th January 2004

18 Crab: 14 th - 15 th February 2004

19 Conclusion / outlook All three samples: clear detection Weak sources (even Crab!) still difficult to analyze. Possible reasons: miss-pointing unstable movement many “dead” pixels

20 Mrk 421 OFF

21 ASYMMETRY

22 Asymmetry: MC photons 73% 27%

23 Asymmetry: MC protons 40% 60%

24 Asymmetry: Mrk 421 ON 44% 56%

25 Asymmetry: Mrk 421 OFF 39% 61%

26 Asymmetry: Crab ON 40% 60%

27 Asymmetry: Crab OFF 38% 62%


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