Astronomy Reports

, Volume 45, Issue 4, pp 249–254 | Cite as

BL Lac: A new ultrahigh-energy gamma-ray source

  • Yu. I. Neshpor
  • N. N. Chalenko
  • A. A. Stepanian
  • O. R. Kalekin
  • N. A. Jogolev
  • V. P. Fomin
  • V. G. Shitov
Article

Abstract

The active galactic nucleus BL Lac was observed with the GT-48 atmospheric Cherenkov detector of the Crimean Astrophysical Observatory from July 23–September 1, 1998, in order to search for ultrahighenergy gamma-ray (>1 TeV) emission. The object was in the field of view of the detector for more than 24 hours. The source was detected with a high level of confidence (7.2 σ) with a flux equal to (2.1±0.4)×10−11 photons cm−2 s−1.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Referecens

  1. 1.
    D. J. Thompson, D. L. Bertsch, B. L. Dingus, et al., Astrophys. J., Suppl. Ser. 101, 259 (1995).CrossRefADSGoogle Scholar
  2. 2.
    J. Quinn, C. W. Akerlof, S. Biller, et al., Astrophys. J. Lett. 456, L83 (1996).ADSGoogle Scholar
  3. 3.
    Yu. I. Neshpor, A. A. Stepanyan, O. R. Kalekin, et al., Pis’ma Astron. Zh. 24, 167 (1998) [Astron. Lett. 24, 134 (1998)].ADSGoogle Scholar
  4. 4.
    G. G. Fazio, H. F. Helmken, E. O. O’Mongain, and T. C. Weekes, Astrophys. J. Lett. 175, L117 (1972).CrossRefADSGoogle Scholar
  5. 5.
    A. A. Stepanyan, B. M. Vladimirskii, Yu. I. Neshpor, and V. P. Fomin, Izv. Krym. Astrofiz. Obs. 53, 29 (1975).ADSGoogle Scholar
  6. 6.
    J. Quinn, C. W. Akerlof, S. Biller, et al., in Proceedings of the 24th International Conference on Cosmic Rays, Roma, 1998, Vol. 2, p. 366.Google Scholar
  7. 7.
    M. Catanese, C. W. Akerlof, S. D. Biller, et al., Astrophys. J. 480, 562 (1997).CrossRefADSGoogle Scholar
  8. 8.
    B. M. Vladimirskii, Yu. L. Zyskin, A. P. Kornienko, et al., Izv. Krym. Astrofiz. Obs. 91, 74 (1995).Google Scholar
  9. 9.
    A. P. Kornienko, A. A. Stepanian, and Yu. L. Zyskin, Astropart. Phys. 1, 245 (1993).CrossRefADSGoogle Scholar
  10. 10.
    O. R. Kalekin, Izv. Krym. Astrofiz. Obs. 95, 167 (1999).Google Scholar
  11. 11.
    A. K. Konopelko and A. V. Plyasheshnikov, Nucl. Instrum. Methods Phys. Res. (2000).Google Scholar
  12. 12.
    B. Wiebel, Fachbereich Physik Bergische Universitet, April 1994, WUB 94-08.Google Scholar
  13. 13.
    C. W. Akerlof, M. F. Cawley, M. Chantell, et al., Astrophys. J. Lett. 377, L97 (1991).CrossRefADSGoogle Scholar
  14. 14.
    Yu. J. Neshpor, A. P. Kornienko, A. A. Stepanian, and Yu. L. Zyskin, Exp. Astron. 5, 405 (1994).CrossRefADSGoogle Scholar
  15. 15.
    V. P. Fomin, S. Fennell, R. C. Lamb, et al., Astropart. Phys. 2, 151 (1994).ADSGoogle Scholar
  16. 16.
    J. H. Fan, G. Z. Xie, E. Pecontal, et al., Astrophys. J. 507, 173 (1998).CrossRefADSGoogle Scholar
  17. 17.
    M. G. Nikolashvili, O. M. Kurtanidze, and G. M. Richter, in Proceedings of the OJ-94 Annual Meeting 1999, Torino, 1999, Ed. by C. M. Raiteri, M. Villata, and L. O. Takalo, p. 33.Google Scholar
  18. 18.
    S. D. Bloom, D. L. Bertsch, R. C. Hartman, et al., Astrophys. J. Lett. 490, L145 (1997).CrossRefADSGoogle Scholar
  19. 19.
    E. S. Perlman, J. T. Stocke, J. F. Schachter, et al., Astrophys. J., Suppl. Ser. 104, 251 (1996).CrossRefADSGoogle Scholar
  20. 20.
    R. C. Hartman, D. L. Bertsch, S. D. Bloom, et al., Astrophys. J., Suppl. Ser. 123, 79 (1999).CrossRefADSGoogle Scholar
  21. 21.
    O. R. Kalekin, Yu. I. Neshpor, A. A. Stepanyan, et al., Pis’ma Astron. Zh. 21(3), 184 (1995) [Astron. Lett. 21, 163 (1995)].ADSGoogle Scholar
  22. 22.
    N. A. Andreeva, Yu. L. Zyskin, O. R. Kalekin, et al., Pis’ma Astron. Zh. 26(3), 243 (2000) [Astron. Lett. 26, 199 (2000)].Google Scholar
  23. 23.
    Yu. I. Neshpor, A. A. Stepanyan, O. R. Kalekin, et al., Astron. Zh. 77, 723 (2000) [Astron. Rep. 44, 641 (2000)].Google Scholar
  24. 24.
    Physics of Space [in Russian], Ed. by R. A. Sunyaev (Moscow, 1986), p. 327.Google Scholar

Copyright information

© MAIK "Nauka/Interperiodica" 2001

Authors and Affiliations

  • Yu. I. Neshpor
    • 1
  • N. N. Chalenko
    • 1
  • A. A. Stepanian
    • 1
  • O. R. Kalekin
    • 1
  • N. A. Jogolev
    • 1
  • V. P. Fomin
    • 1
  • V. G. Shitov
    • 1
  1. 1.Crimean Astrophysical ObservatoryCrimea

Personalised recommendations