|
|||||
|
|
Gamma–hadron separation methods for the VERITAS array of four imaging atmospheric Cherenkov telescopes |
|
| Authors: | H Krawczynski DA Carter-Lewis C Duke J Holder G Maier S Le Bohec G Sembroski |
| Institution: | aDepartment of Physics, Washington University in St. Louis, 1 Brookings Drive, CB 1105, St. Louis, MO 63130, USA bDepartment of Physics and Astronomy, Iowa State University, Ames, IA 50011-3160, USA cDepartment of Physics, Grinnell College, Grinnell, IA 50112-1690, USA dSchool of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, Yorkshire, UK eHigh Energy Astrophysics Institute, University of Utah, Salt Lake City, UT 84112, USA fDepartment of Physics, Purdue University, West Lafayette, IN 47907, USA |
| Abstract: | Ground-based arrays of imaging atmospheric Cherenkov telescopes have emerged as the most sensitive γ-ray detectors in the energy range of about 100 GeV and above. The strengths of these arrays are a very large effective collection area on the order of 105 m2, combined with excellent single photon angular and energy resolutions. The sensitivity of such detectors is limited by statistical fluctuations in the number of Cosmic-ray initiated air showers that resemble γ-ray air showers in many ways. In this paper, we study the performance of simple event reconstruction methods when applied to simulated data of the Very Energetic Radiation Imaging Telescope Array System (VERITAS) experiment. We review methods for reconstructing the arrival direction and the energy of the primary photons, and examine means to improve on their performance. For a software threshold energy of 300 GeV (100 GeV), the methods achieve point source angular and energy resolutions of σ63% = 0.1° (0.2°) and σ68% = 15% (22%), respectively. The main emphasis of the paper is the discussion of γ–hadron separation methods for the VERITAS experiment. We find that the information from several methods can be combined based on a likelihood ratio approach and the resulting algorithm achieves a γ–hadron suppression with a quality factor that is substantially higher than that achieved with the standard methods used so far. |
| Keywords: | γ-Ray observations Data analysis methods Imaging atmospheric Cherenkov telescopes |
| 本文献已被 ScienceDirect 等数据库收录！ | |