Detection of multi-TeV gamma rays from Markarian 501 during an unforeseen flaring state in 1997 with the Tibet air shower array

M. Amenomori, S. Ayabe, P. Y. Cao, Danzengluobu, L. K. Ding, Z. Y. Feng, Y. Fu, H. W. Guo, M. He, K. Hibino, N. Hotta, Q. Huang, A. X. Huo, K. Izu, H. Y. Jia, F. Kajino, K. Kasahara, Y. Katayose, Labaciren, J. Y. Li & 40 others H. Lu, S. L. Lu, G. X. Luo, X. R. Meng, K. Mizutani, J. Mu, H. Nanjo, M. Nishizawa, M. Ohnishi, I. Ohta, T. Ouchi, J. R. Ren, T. Saito, M. Sakata, T. Sasaki, Z. Z. Shi, M. Shibata, A. Shiomi, T. Shirai, H. Sugimoto, K. Taira, Y. H. Tan, N. Tateyama, Shoji Torii, T. Utsugi, C. R. Wang, H. Wang, X. W. Xu, Y. Yamamoto, G. C. Yu, A. F. Yuan, T. Yuda, C. S. Zhang, H. M. Zhang, J. L. Zhang, N. J. Zhang, X. Y. Zhang, Zhaxisangzhu, Zhaxiciren, W. D. Zhou

Research output: Contribution to journalArticle

51 Citations (Scopus)

Abstract

In 1997, the BL Lac object Mrk 501 entered a very active phase and was the brightest source in the sky at TeV energies, showing strong and frequent flaring. Using the data obtained with a high-density air shower array that has been operating successfully at Yangbajing in Tibet since 1996, we searched for γ-ray signals from this source during the period in 1997 from February through August. Our observation detected multi-TeV γ-ray signals at the 3.7 σ level during this period. The most rapid increase in the excess counts was observed between April 7 and June 16, and the statistical significance of the excess counts in this period was 4.7 σ. Among several observations of flaring TeV γ-rays from Mrk 501 in 1997, this is the only observation using a conventional air shower array. We present the energy spectrum of γ-rays, which will be worth comparing with those obtained by imaging atmospheric Cerenkov telescopes.

Original languageEnglish
Pages (from-to)302-307
Number of pages6
JournalAstrophysical Journal
Volume532
Issue number1 PART 1
Publication statusPublished - 2000 Mar 20
Externally publishedYes

Fingerprint

Tibet
cosmic ray showers
rays
gamma rays
air
energy
sky
energy spectra
telescopes
flaring
detection

Keywords

  • BL Lacertae objects: individual (Markarian 501)
  • Gamma rays: observations

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Amenomori, M., Ayabe, S., Cao, P. Y., Danzengluobu, Ding, L. K., Feng, Z. Y., ... Zhou, W. D. (2000). Detection of multi-TeV gamma rays from Markarian 501 during an unforeseen flaring state in 1997 with the Tibet air shower array. Astrophysical Journal, 532(1 PART 1), 302-307.

Detection of multi-TeV gamma rays from Markarian 501 during an unforeseen flaring state in 1997 with the Tibet air shower array. / Amenomori, M.; Ayabe, S.; Cao, P. Y.; Danzengluobu; Ding, L. K.; Feng, Z. Y.; Fu, Y.; Guo, H. W.; He, M.; Hibino, K.; Hotta, N.; Huang, Q.; Huo, A. X.; Izu, K.; Jia, H. Y.; Kajino, F.; Kasahara, K.; Katayose, Y.; Labaciren; Li, J. Y.; Lu, H.; Lu, S. L.; Luo, G. X.; Meng, X. R.; Mizutani, K.; Mu, J.; Nanjo, H.; Nishizawa, M.; Ohnishi, M.; Ohta, I.; Ouchi, T.; Ren, J. R.; Saito, T.; Sakata, M.; Sasaki, T.; Shi, Z. Z.; Shibata, M.; Shiomi, A.; Shirai, T.; Sugimoto, H.; Taira, K.; Tan, Y. H.; Tateyama, N.; Torii, Shoji; Utsugi, T.; Wang, C. R.; Wang, H.; Xu, X. W.; Yamamoto, Y.; Yu, G. C.; Yuan, A. F.; Yuda, T.; Zhang, C. S.; Zhang, H. M.; Zhang, J. L.; Zhang, N. J.; Zhang, X. Y.; Zhaxisangzhu; Zhaxiciren; Zhou, W. D.

In: Astrophysical Journal, Vol. 532, No. 1 PART 1, 20.03.2000, p. 302-307.

Research output: Contribution to journalArticle

Amenomori, M, Ayabe, S, Cao, PY, Danzengluobu, Ding, LK, Feng, ZY, Fu, Y, Guo, HW, He, M, Hibino, K, Hotta, N, Huang, Q, Huo, AX, Izu, K, Jia, HY, Kajino, F, Kasahara, K, Katayose, Y, Labaciren, Li, JY, Lu, H, Lu, SL, Luo, GX, Meng, XR, Mizutani, K, Mu, J, Nanjo, H, Nishizawa, M, Ohnishi, M, Ohta, I, Ouchi, T, Ren, JR, Saito, T, Sakata, M, Sasaki, T, Shi, ZZ, Shibata, M, Shiomi, A, Shirai, T, Sugimoto, H, Taira, K, Tan, YH, Tateyama, N, Torii, S, Utsugi, T, Wang, CR, Wang, H, Xu, XW, Yamamoto, Y, Yu, GC, Yuan, AF, Yuda, T, Zhang, CS, Zhang, HM, Zhang, JL, Zhang, NJ, Zhang, XY, Zhaxisangzhu, Zhaxiciren & Zhou, WD 2000, 'Detection of multi-TeV gamma rays from Markarian 501 during an unforeseen flaring state in 1997 with the Tibet air shower array', Astrophysical Journal, vol. 532, no. 1 PART 1, pp. 302-307.
Amenomori M, Ayabe S, Cao PY, Danzengluobu, Ding LK, Feng ZY et al. Detection of multi-TeV gamma rays from Markarian 501 during an unforeseen flaring state in 1997 with the Tibet air shower array. Astrophysical Journal. 2000 Mar 20;532(1 PART 1):302-307.
Amenomori, M. ; Ayabe, S. ; Cao, P. Y. ; Danzengluobu ; Ding, L. K. ; Feng, Z. Y. ; Fu, Y. ; Guo, H. W. ; He, M. ; Hibino, K. ; Hotta, N. ; Huang, Q. ; Huo, A. X. ; Izu, K. ; Jia, H. Y. ; Kajino, F. ; Kasahara, K. ; Katayose, Y. ; Labaciren ; Li, J. Y. ; Lu, H. ; Lu, S. L. ; Luo, G. X. ; Meng, X. R. ; Mizutani, K. ; Mu, J. ; Nanjo, H. ; Nishizawa, M. ; Ohnishi, M. ; Ohta, I. ; Ouchi, T. ; Ren, J. R. ; Saito, T. ; Sakata, M. ; Sasaki, T. ; Shi, Z. Z. ; Shibata, M. ; Shiomi, A. ; Shirai, T. ; Sugimoto, H. ; Taira, K. ; Tan, Y. H. ; Tateyama, N. ; Torii, Shoji ; Utsugi, T. ; Wang, C. R. ; Wang, H. ; Xu, X. W. ; Yamamoto, Y. ; Yu, G. C. ; Yuan, A. F. ; Yuda, T. ; Zhang, C. S. ; Zhang, H. M. ; Zhang, J. L. ; Zhang, N. J. ; Zhang, X. Y. ; Zhaxisangzhu ; Zhaxiciren ; Zhou, W. D. / Detection of multi-TeV gamma rays from Markarian 501 during an unforeseen flaring state in 1997 with the Tibet air shower array. In: Astrophysical Journal. 2000 ; Vol. 532, No. 1 PART 1. pp. 302-307.
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title = "Detection of multi-TeV gamma rays from Markarian 501 during an unforeseen flaring state in 1997 with the Tibet air shower array",
abstract = "In 1997, the BL Lac object Mrk 501 entered a very active phase and was the brightest source in the sky at TeV energies, showing strong and frequent flaring. Using the data obtained with a high-density air shower array that has been operating successfully at Yangbajing in Tibet since 1996, we searched for γ-ray signals from this source during the period in 1997 from February through August. Our observation detected multi-TeV γ-ray signals at the 3.7 σ level during this period. The most rapid increase in the excess counts was observed between April 7 and June 16, and the statistical significance of the excess counts in this period was 4.7 σ. Among several observations of flaring TeV γ-rays from Mrk 501 in 1997, this is the only observation using a conventional air shower array. We present the energy spectrum of γ-rays, which will be worth comparing with those obtained by imaging atmospheric Cerenkov telescopes.",
keywords = "BL Lacertae objects: individual (Markarian 501), Gamma rays: observations",
author = "M. Amenomori and S. Ayabe and Cao, {P. Y.} and Danzengluobu and Ding, {L. K.} and Feng, {Z. Y.} and Y. Fu and Guo, {H. W.} and M. He and K. Hibino and N. Hotta and Q. Huang and Huo, {A. X.} and K. Izu and Jia, {H. Y.} and F. Kajino and K. Kasahara and Y. Katayose and Labaciren and Li, {J. Y.} and H. Lu and Lu, {S. L.} and Luo, {G. X.} and Meng, {X. R.} and K. Mizutani and J. Mu and H. Nanjo and M. Nishizawa and M. Ohnishi and I. Ohta and T. Ouchi and Ren, {J. R.} and T. Saito and M. Sakata and T. Sasaki and Shi, {Z. Z.} and M. Shibata and A. Shiomi and T. Shirai and H. Sugimoto and K. Taira and Tan, {Y. H.} and N. Tateyama and Shoji Torii and T. Utsugi and Wang, {C. R.} and H. Wang and Xu, {X. W.} and Y. Yamamoto and Yu, {G. C.} and Yuan, {A. F.} and T. Yuda and Zhang, {C. S.} and Zhang, {H. M.} and Zhang, {J. L.} and Zhang, {N. J.} and Zhang, {X. Y.} and Zhaxisangzhu and Zhaxiciren and Zhou, {W. D.}",
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TY - JOUR

T1 - Detection of multi-TeV gamma rays from Markarian 501 during an unforeseen flaring state in 1997 with the Tibet air shower array

AU - Amenomori, M.

AU - Ayabe, S.

AU - Cao, P. Y.

AU - Danzengluobu,

AU - Ding, L. K.

AU - Feng, Z. Y.

AU - Fu, Y.

AU - Guo, H. W.

AU - He, M.

AU - Hibino, K.

AU - Hotta, N.

AU - Huang, Q.

AU - Huo, A. X.

AU - Izu, K.

AU - Jia, H. Y.

AU - Kajino, F.

AU - Kasahara, K.

AU - Katayose, Y.

AU - Labaciren,

AU - Li, J. Y.

AU - Lu, H.

AU - Lu, S. L.

AU - Luo, G. X.

AU - Meng, X. R.

AU - Mizutani, K.

AU - Mu, J.

AU - Nanjo, H.

AU - Nishizawa, M.

AU - Ohnishi, M.

AU - Ohta, I.

AU - Ouchi, T.

AU - Ren, J. R.

AU - Saito, T.

AU - Sakata, M.

AU - Sasaki, T.

AU - Shi, Z. Z.

AU - Shibata, M.

AU - Shiomi, A.

AU - Shirai, T.

AU - Sugimoto, H.

AU - Taira, K.

AU - Tan, Y. H.

AU - Tateyama, N.

AU - Torii, Shoji

AU - Utsugi, T.

AU - Wang, C. R.

AU - Wang, H.

AU - Xu, X. W.

AU - Yamamoto, Y.

AU - Yu, G. C.

AU - Yuan, A. F.

AU - Yuda, T.

AU - Zhang, C. S.

AU - Zhang, H. M.

AU - Zhang, J. L.

AU - Zhang, N. J.

AU - Zhang, X. Y.

AU - Zhaxisangzhu,

AU - Zhaxiciren,

AU - Zhou, W. D.

PY - 2000/3/20

Y1 - 2000/3/20

N2 - In 1997, the BL Lac object Mrk 501 entered a very active phase and was the brightest source in the sky at TeV energies, showing strong and frequent flaring. Using the data obtained with a high-density air shower array that has been operating successfully at Yangbajing in Tibet since 1996, we searched for γ-ray signals from this source during the period in 1997 from February through August. Our observation detected multi-TeV γ-ray signals at the 3.7 σ level during this period. The most rapid increase in the excess counts was observed between April 7 and June 16, and the statistical significance of the excess counts in this period was 4.7 σ. Among several observations of flaring TeV γ-rays from Mrk 501 in 1997, this is the only observation using a conventional air shower array. We present the energy spectrum of γ-rays, which will be worth comparing with those obtained by imaging atmospheric Cerenkov telescopes.

AB - In 1997, the BL Lac object Mrk 501 entered a very active phase and was the brightest source in the sky at TeV energies, showing strong and frequent flaring. Using the data obtained with a high-density air shower array that has been operating successfully at Yangbajing in Tibet since 1996, we searched for γ-ray signals from this source during the period in 1997 from February through August. Our observation detected multi-TeV γ-ray signals at the 3.7 σ level during this period. The most rapid increase in the excess counts was observed between April 7 and June 16, and the statistical significance of the excess counts in this period was 4.7 σ. Among several observations of flaring TeV γ-rays from Mrk 501 in 1997, this is the only observation using a conventional air shower array. We present the energy spectrum of γ-rays, which will be worth comparing with those obtained by imaging atmospheric Cerenkov telescopes.

KW - BL Lacertae objects: individual (Markarian 501)

KW - Gamma rays: observations

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M3 - Article

VL - 532

SP - 302

EP - 307

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1 PART 1

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