トラマツ チエ
  寅松 千枝
   所属   医学部 医学科(東京女子医科大学病院)
   職種   非常勤講師
論文種別 原著
言語種別 英語
査読の有無 査読あり
表題 Observation of Gamma Rays Greater than 10 TeV from Markarian 421
掲載誌名 正式名:The Astrophysical Journal Letters
掲載区分国外
巻・号・頁 579(1),pp.9-12
著者・共著者 K. Okumura, A. Asahara, G. V. Bicknell, P. G. Edwards, R. Enomoto, S. Gunji, S. Hara, T. Hara, S. Hayashi, C. Itoh (Toramatsu), S. Kabuki, F. Kajino, H. Katagiri, J. Kataoka, A. Kawachi, T. Kifune, H. Kubo, J. Kushida, S. Maeda, A. Maeshiro, Y. Matsubara, Y. Mizumoto, M. Mori, M. Moriya, H. Muraishi, Y. Muraki, T. Naito, T. Nakase, K. Nishijima, M. Ohishi,
J. R. Patterson, K. Sakurazawa, R. Suzuki, D. L. Swaby, K. Takano, T. Takano, T. Tanimori, F. Tokanai, K. Tsuchiya, H. Tsunoo, K. Uruma, A. Watanabe,
S. Yanagita, T. Yoshida, T. Yoshikoshi
発行年月 2002/11/01
概要 We have observed Markarian 421 in 2001 January and March with the CANGAROO-II imaging Cerenkov
telescope during an extraordinarily high state at TeV energies. From 14 hr of observations at very large zenith
angles, ∼70, a signal of gamma-ray–like events (5.7 298 52 j) was detected at TeV, where a higher E 1 10
sensitivity is achieved than those of usual observations near the zenith, owing to a greatly increased collecting area.
Under the assumption of an intrinsic power-law spectrum, we derived a differential energy spectrum dN/dE p
photons cm2 s
1 TeV1
, which is steeper than those  0.9 13 (4.00.6, stat syst 0.3 ) (3.3 0.9 0.3 ) # 10 (E/10 TeV) stat syst
previously measured around 1 TeV and supports the evidence for a cutoff in the spectrum of Mrk 421. However,
the 4 j excess at energies greater than 20 TeV in our data favors a cutoff energy of ∼8 TeV, at the upper end of
the range previously reported from measurements at TeV energies.