Multi-TeV gamma-ray flares from Markarian 421 in 2000 and 2001 observed with the Tibet air shower array

M. Amenomori*, S. Ayabe, S. W. Cui, Danzenoluobu, L. K. Ding, X. H. Ding, C. F. Feng, Z. Y. Feng, X. Y. Gao, Q. X. Geng, H. W. Guo, H. H. He, M. He, K. Hibino, N. Hotta, Hu Haibing, H. B. Hu, J. Huang, Q. Huang, H. Y. JiaF. Kajino, K. Kasahara, Y. Katayose, K. Kawata, Labaciren, G. M. Le, J. Y. Li, H. Lu, S. L. Lu, X. R. Meng, K. Mizutani, J. Mu, H. Nanjo, M. Nishizawa, M. Ohnishi, I. Ohta, T. Ouchi, Shunsuke Ozawa, J. R. Ren, T. Saito, M. Sakata, T. Sasaki, M. Shibata, A. Shiomi, T. Shirai, H. Sugimoto, K. Taira, M. Takita, Y. H. Tan, N. Tateyama, Shoji Torii, H. Tsuchiya, S. Udo, T. Utsugi, B. S. Wang, H. Wang, X. Wang, Y. G. Wang, L. Xue, Y. Yamamoto, X. C. Yang, Z. H. Ye, G. C. Yu, A. F. Yuan, T. Yuda, H. M. Zhang, J. L. Zhang, N. J. Zhang, X. Y. Zhang, Y. Zhang, Zhaxisangzhu, X. X. Zhou

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

84 Citations (Scopus)


Several strong TeV γ-ray flares were detected from Mrk 421 in the years 2000 and 2001 by the Tibet III air shower array at a level of statistical significance of 5.1 σ. Mrk 421 was unprecedentedly active at X-ray and TeV γ-ray energies during this period, and a positive correlation was found between the change of the all-sky monitor Rossi X-Ray Timing Explorer X-ray flux and the Tibet TeV γ-ray flux. When a power-law energy spectrum for γ-rays from this source is assumed, the spectral index is calculated to be -3.24 ± 0.69 at the most active phase in 2001. The spectral index observed by the Tibet air shower array is consistent with those obtained via imaging air Cerenkov telescopes.

Original languageEnglish
Pages (from-to)242-249
Number of pages8
JournalAstrophysical Journal
Issue number1 I
Publication statusPublished - 2003 Nov 20
Externally publishedYes


  • BL Lacertae objects: individual (Markarian 421)
  • Gamma rays: observations

ASJC Scopus subject areas

  • Space and Planetary Science


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