TY - JOUR
T1 - Handling systematic uncertainties and combined source analyses for Atmospheric Cherenkov Telescopes
AU - Dickinson, Hugh
AU - Conrad, Jan
PY - 2013
Y1 - 2013
N2 - In response to an increasing availability of statistically rich observational data sets, the performance and applicability of traditional Atmospheric Cherenkov Telescope analyses in the regime of systematically dominated measurement uncertainties is examined. In particular, the effect of systematic uncertainties affecting the relative normalisation of fiducial ON and OFF-source sampling regions - often denoted as a - is investigated using combined source analysis as a representative example case. The traditional summation of accumulated ON and OFF-source event counts is found to perform sub-optimally in the studied contexts and requires careful calibration to correct for unexpected and potentially misleading statistical behaviour. More specifically, failure to recognise and correct for erroneous estimates of a is found to produce substantial overestimates of the combined population significance which worsen with increasing target multiplicity. An alternative joint likelihood technique is introduced, which is designed to treat systematic uncertainties in a uniform and statistically robust manner. This alternate method is shown to yield dramatically enhanced performance and reliability with respect to the more traditional approach.
AB - In response to an increasing availability of statistically rich observational data sets, the performance and applicability of traditional Atmospheric Cherenkov Telescope analyses in the regime of systematically dominated measurement uncertainties is examined. In particular, the effect of systematic uncertainties affecting the relative normalisation of fiducial ON and OFF-source sampling regions - often denoted as a - is investigated using combined source analysis as a representative example case. The traditional summation of accumulated ON and OFF-source event counts is found to perform sub-optimally in the studied contexts and requires careful calibration to correct for unexpected and potentially misleading statistical behaviour. More specifically, failure to recognise and correct for erroneous estimates of a is found to produce substantial overestimates of the combined population significance which worsen with increasing target multiplicity. An alternative joint likelihood technique is introduced, which is designed to treat systematic uncertainties in a uniform and statistically robust manner. This alternate method is shown to yield dramatically enhanced performance and reliability with respect to the more traditional approach.
KW - Combined source analysis
KW - Data stacking
KW - Gamma-ray astronomy
KW - Likelihood analysis
KW - Stacking analysis
KW - Statistical analysis
KW - Systematic uncertainties
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U2 - 10.1016/j.astropartphys.2012.10.004
DO - 10.1016/j.astropartphys.2012.10.004
M3 - Article
AN - SCOPUS:84870320853
SN - 0927-6505
VL - 41
SP - 17
EP - 30
JO - Astroparticle Physics
JF - Astroparticle Physics
ER -