OBSERVATION OF TeV GAMMA RAYS FROM THE FERMI BRIGHT GALACTIC SOURCES WITH THE TIBET AIR SHOWER ARRAY
- Department of Physics, Hirosaki University, Hirosaki 036-8561 (Japan)
- Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)
- Institute for Cosmic Ray Research, University of Tokyo, Kashiwa 277-8582 (Japan)
- Department of Physics, Hebei Normal University, Shijiazhuang 050016 (China)
- Department of Mathematics and Physics, Tibet University, Lhasa 850000 (China)
- Department of Physics, Shandong University, Jinan 250100 (China)
- Institute of Modern Physics, SouthWest Jiaotong University, Chengdu 610031 (China)
- Department of Physics, Yunnan University, Kunming 650091 (China)
- Faculty of Engineering, Kanagawa University, Yokohama 221-8686 (Japan)
- Faculty of Education, Utsunomiya University, Utsunomiya 321-8505 (Japan)
Using the Tibet-III air shower array, we search for TeV {gamma}-rays from 27 potential Galactic sources in the early list of bright sources obtained by the Fermi Large Area Telescope at energies above 100 MeV. Among them, we observe seven sources instead of the expected 0.61 sources at a significance of 2{sigma} or more excess. The chance probability from Poisson statistics would be estimated to be 3.8 x 10{sup -6}. If the excess distribution observed by the Tibet-III array has a density gradient toward the Galactic plane, the expected number of sources may be enhanced in chance association. Then, the chance probability rises slightly, to 1.2 x 10{sup -5}, based on a simple Monte Carlo simulation. These low chance probabilities clearly show that the Fermi bright Galactic sources have statistically significant correlations with TeV {gamma}-ray excesses. We also find that all seven sources are associated with pulsars, and six of them are coincident with sources detected by the Milagro experiment at a significance of 3{sigma} or more at the representative energy of 35 TeV. The significance maps observed by the Tibet-III air shower array around the Fermi sources, which are coincident with the Milagro {>=}3{sigma} sources, are consistent with the Milagro observations. This is the first result of the northern sky survey of the Fermi bright Galactic sources in the TeV region.
- OSTI ID:
- 21301402
- Journal Information:
- Astrophysical Journal Letters, Vol. 709, Issue 1; Other Information: DOI: 10.1088/2041-8205/709/1/L6; Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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