Itoh, ChieEnomoto, RYanagita, SYoshida, TTanimori, TOkumura, KAsahara, ABicknell, GeoffreyClay, Roger WEdwards, Philip GGunji, SHara, ShinjiHara, THattori, THayashi, SeiHayashi, SeuchiKabuki, SKajino, FKatagiri, HKawachi, AKifune, TadashiKubo, HKushida, JMatsubara, YMizumoto, YMori, MasakiMoro, HMuraishi, HMuraki, YNaito, TNakase, TNishida, DNishijima, KOhishi, MPatterson, Joseph RProtheroe, RaymondSakurazawa, KSwaby, D LTokanai, FTsuchiya, KTsunoo, HUchida, TWatanabe, OWatanabe, SYoshikoshi, T2015-12-132015-12-130004-6361http://hdl.handle.net/1885/88038TeV gamma-rays were recently detected from the nearby normal spiral galaxy NGC 253 (Itoh et al. 2002). Observations to detect the Cherenkov light images initiated by gamma-rays from the direction of NGC 253 were carried out in 2000 and 2001 over a total period of ∼150 hours. The orientation of images in gamma-ray-like events is not consistent with emission from a point source, and the emission region corresponds to a size greater than 10 kpc in radius. Here, detailed descriptions of the analysis procedures and techniques are given.Keywords: Cerenkov counters; Cosmic rays; Gamma rays; Photoemission; Cosmic dust; Galaxies Galaxies: halos; Galaxies: individual: NGC 253; Galaxies: starburst; Gamma rays: observation; ISM: cosmic rays20032015-12-12