Abstract
One of the major goals in VHE-γ-ray astronomy is to open the energy range below 100 GeV with earthbound detectors. This paper demonstrates a new method for analyzing Čerenkov light of a shower in a Čerenkov telescope array. This method is successful for showers in this low energy regime where previous techniques (e.g. alpha analysis) are not applicable. A Monte Carlo simulation is applied to a system of 19 Whipple type [3, Cawley 1990] Imaging Atmospheric Čerenkov telescopes (IAČT), each built as a 10 m diameter reflector and equipped with a 109 photomultiplier tube camera. The energy threshold for a single detector of this type is given [5, Kerrick et al. 1995] as 250 GeV. Analysis of simulated coincident events of the system for those events not having enough light to apply a standard imaging analysis [4, Hillas 1985], leads to a considerably lower threshold of 85 GeV. With a new analysis method of these events it is shown that it should be possible to distinguish between γ-ray induced and proton induced showers. The improvement of sensitivity (Q = figure of merit) of this analysis method is found to be Q=2.9.
Similar content being viewed by others
References
F.A. Aharonian et al., in Proc. of “Towards a Major Atmospheric Cerenkov Detector” (Calgary), 81 (1993)
O.R. Kalekin et al., in Proc. of “Towards a Major Atmospheric Cerenkov Detector” (Tokyo), 107 (1994)
M.F.Cawley et al., Experimental Astronomy, 1, 173–193 (1990)
A.M. Hillas, in Proc. of 19th ICRC (La Jolla), vol. 3, p445 (1985)
A.D.Kerrick et al., ApJ, 438, L59-L62 (1995)
M.Kertzman & G.H.Sembroski, NIM, A343 (1994) 629–643
T. Kifune, in Proc. of “Towards a Major Atmospheric Cerenkov Detector” (Palaiseau), 229 (1992)
D.A.Lewis, Experimental Astronomy, 1, 213–226 (1990)
R.Mirzoyan et al., NIM, A351, 513–526 (1994)
M. Teshima et al., in Proc. of “Towards a Major Atmospheric Cerenkov Detector” (Palaiseau), 255 (1992)
P.M. Chadwick et al., to be published in Space Science Reviews (1995)
G.H. Sembroski et al., to be published in the proceedings of 24th ICRC (Rome) (1995)
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Krennrich, F., Lamb, R.C. Low energy γ-ray events in imaging Čerenkov telescope arrays. Experimental Astronomy 6, 285–292 (1995). https://doi.org/10.1007/BF00418326
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00418326