The effect of the fluorescence yield selection on the energy scales of Auger, HiRes and TA

Abstract

Abstract. The fluorescence yield data used for shower reconstruction in the Auger, HiRes and TA experiments are different, not only in the overall absolute value but also in the wavelength spectrum and the various atmospheric dependencies. The effect on the energy reconstruction of using different fluorescence yield parameterizations is discussed. In addition, the impact of a change in the fluorescence spectrum depends on the optical efficiency of the telescopes. A simple analytical procedure allows us to evaluate the combined effect of fluorescence yield and optical efficiency showing a non-negligible deviation between the energy scales of TA and Auger. However no relevant effect is found in the comparison between HiRes and Auger. Finally we show that a similar procedure could also be applied with real data.

Relevance of the fluorescence radiation in VHE gamma-ray observations with the Cherenkov technique

“…The wavelength interval for these calculations was extended to 280 − 700 nm to include some other weak bands of the 2P and 1N systems, for which we used the corresponding branching ratios and assumed P ∝ T 1/2 [20]. The effect of the selection of air-fluorescence parameters in the reconstruction of EASs has been studied in [24,25].…”