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S earch for neutrino emission from 
 the Fermi Bubbles with the ANTARES telescope

S earch for neutrino emission from 
 the Fermi Bubbles with the ANTARES telescope. Vladimir Kulikovskiy. Overview. Last updates of the analysis sparking events cut energy shift of the MC limits calculation Short overview of analysis. Sparking events cut. Two possibilities were studied

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S earch for neutrino emission from 
 the Fermi Bubbles with the ANTARES telescope

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  1. Search for neutrino emission from 
 the Fermi Bubbles with the ANTARES telescope Vladimir Kulikovskiy

  2. Overview • Last updates of the analysis • sparking events cut • energy shift of the MC • limits calculation • Short overview of analysis

  3. Sparking events cut • Two possibilities were studied • EventDisplay-like cut “tχ2 < bχ2” • Cut on the distance to the OMs

  4. 3/10 events with the highest EANN (5.3, 4.6, 4.6) are identified as Bright Point events on event display • EventDisplay has a selection tχ2 < bχ2 to decide which fit to show

  5. Additional tχ2 < bχ2 reduces the data, while MC stays on the same level -> the data/MC comparison improves. • This means that cut is efficient against events which are not present in the MC.

  6. sparking run 38347 • Bbbfit bright point (standalone)

  7. Seatray production • Distance to the closest OM • Black – events in the sparking spot • Blue – outside. • density of the events from the distance to the closest OM for the events inside the spot.

  8. Conclusion 1 • tχ2 < bχ2 is efficient against sparking events • distance to the OM cut is interesting, but more study is needed.

  9. reconstructed energy of the MC events seems to be lower than of the data events • in log scale it may be interpreted as a shift • The reason may be overestimated water properties. An absorption length increase from 55 to 63 m produces a shift of logE=0.2 • The proper tests was done by Dimitris in his thesis work. • MC1: ang. acc. dic08 and a maximum absorption length of 55 m at 470 nm. • MC2: ang.acc. jun09 and scaled absorption length with a maximum of 63m at 470nm.

  10. MC was scaled by 23% (obtained by λ distribution fit) • shift was fitted with a chi2 and Kolmogorov-Smirnov test by shifting on a bin size (logE=0.03) • The best shift obtained was logE=0.1 by both fits • Kolmogorov-Smirnov probability is 0.3 after the scale and shift

  11. MRF optimization

  12. Limits calculation • Black - Bayesian approach (Nbg = 33) • Red - Feldman & Cousins approach with b = 11 • Blue - Conrad's approach with b = 11±2 • Limits calculated • as a flux for 100 TeV cut • without 30% systematics (black) • including it (red).

  13. Short overview of the analysis • 12 line data 2008-2011 • prod 2012-04 and MC v2+v2.2 • runs • QB≥1 • no SCAN no sparking runs • good data/MC ratio • precut • λ>-6 • β<1o • nhits>10 • up-going • tχ2 < bχ2 • Difference between number of events in the zones study – 1% syst. error. • Data/MC comparison: • Scale of MC (atmospheric nu,mu) • Energy shift of MC (atmospheric nu,mu,signal) • Limits calculations using the Bayesian approach (check with F&C, Conrad)

  14. Summary • Study of the weak points of the first analysis was done. • Questions from referees were answered (some of them are reported on the wiki). • An analysis note is written and distributed 5 days before today. • Wiki page with a lot of supporting information is written.

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