Introduction to Irene’s talk (reminder) Coincidence window 500s GWHEN group, Astropart. Phys. 35 (2011) 1-7 Ph. D Thesis of I. Di Palma (AEI) Ph. D Thesis of B. Bouhou (APC) Updates on this work: - 17 May - 20 May Clermont-Ferrand meeting (2010) - 20 Sep - 24 Sep Paris meeting (2010) - 22 Nov - 25 Nov Amsterdam meeting (2010) - 07 Feb - 10 Feb CERN meeting (2011) - 06 Jun - 10 Jun Moscow meeting (2011) Internal note: ANTARES-PHYS-2011-003 wiki page: http://antares.in2p3.fr/internal/dokuwiki/doku.php?id=li The selection criteria follow G. Halladjian’s strategy Optimization for (steady) PS E -2 Unblinding granted before summer 2010 (Referee: Aart Heijboer) 2007 analysis’ scheme (triggered search)
Introduction to Irene’s talk (reminder). The 2007 analysis’ scheme (triggered search). Ph. D Thesis of B. Bouhou (APC). Updates on this work: - 17 May - 20 May Clermont-Ferrand meeting (2010) - 20 Sep - 24 Sep Paris meeting (2010) - 22 Nov - 25 Nov Amsterdam meeting (2010) - PowerPoint PPT Presentation
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Data and MC sample are reconstructed with the BBfit reconstruction package (v3r6)
Cosmic neutrinos :
MC sample
Better angular accuracy than if taking random track solution Smaller search box for GW detectors
Two possible tracks(Mirror solution)
Two possible azimuth values (Same zenith)
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Track 1
Track 2
Detector line
Reconstruction used
• Events reconstructed with 2 lines
== Due to simplified detector geometry ==
• The version of the reconstruction offers the possibility to get the azimuth of the mirror solution in the case of events reconstructed with two lines
Cut optimizationCut are applied to maximize the discovery potential in search for E-2 point sourcesOnly up-going events are considered.Method : test statistics LR to get optimum nsig
Different values of track and bright point 2 for different zenith angles are tested 70 possible combinations
G. Halladjian, Ph. D, University Marseilles, Dec 2010
Chosen cuts (up-going events)• b2 >2.2 (reduced contamination ofatmospheric muons)• t2 <=1.8 for zenith<80° • t2 <=1.4 for 80°<zenith<90°
• 20% contamination from atmosphericmuons
for zenith<80°
for 80°<zenith<90°
Angular search window
βμ
ν
The space angle β between the true neutrino direction and the reconstructed muon direction (E-2 spectrum) defines the angular accuracy
The angular search window is defined as 50% quantile ( or 90% quantile ) of the β distribution in bins of reconstructed declination (10°) and number of hits
90% quantile
nhit=7
Log-normal (instead of Fisher) distributions are fitted and provided for processing with X-pipeline (weight the scan directions inside the angular window)
θ is the location parameter
m is the scale parameterσ is the shape parameter
The HEN candidate list time Dec(°) RA (°) lines hits ASW(50%) ASW(90%) weight
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• 18 events reconstructed with 3 lines and more.• 198 events reconstructed with exactly two lines : 2 solutions• Total number of events ( 18 + 2*198 )
Spare
Coincidence window
Fig. 1. (a) active central engine before the relativistic jet has broken out of the stellar envelope; (b) active central engine with the relativistic jet broken out of the envelope; (c) delay between the onset of the precursor and the main burst; (d) duration corresponding to 90% of GeV photon emission; (e) time span of central engine activity.
Based on BATSE T90’sAnd FERMI-LAT data
Collapsar modelTime to break out envelope
Opaque to ’s
Precursors were observed for ~15% of GRBs (long and short (8%)) Emission mechanisms might be that of prompt GRBs same model
PrecursorUpper bound for BATSE
GWHEN group, Astropart. Phys. 35 (2011) 1-7
Angular search window
βμ
ν
The error β on the neutrino direction is defined as the angular difference between the true neutrino direction and the reconstructed muon direction (E-2 spectrum)
The angular search window is defined as 50% quantile ( or 90% quantile ) of the β distribution in bins of reconstructed declination (10°) and number of hits