Handling systematic uncertainties and combined source analyses for Atmospheric Cherenkov Telescopes
2013 (English)In: Astroparticle physics, ISSN 0927-6505, E-ISSN 1873-2852, Vol. 41, 17-30 p.Article in journal (Refereed) Published
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 alpha - 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 alpha 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.
Place, publisher, year, edition, pages
2013. Vol. 41, 17-30 p.
Gamma-ray astronomy, Systematic uncertainties, Combined source analysis, Stacking analysis, Data stacking, Statistical analysis, Likelihood analysis
Astronomy, Astrophysics and Cosmology
IdentifiersURN: urn:nbn:se:su:diva-88356DOI: 10.1016/j.astropartphys.2012.10.004ISI: 000314442600003OAI: oai:DiVA.org:su-88356DiVA: diva2:613022