Observation of TeV Gamma Rays from the Fermi Bright Galactic Sources with the Tibet Air Shower Array
Abstract
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 7 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^-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^-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 7 sources are associated with pulsars, and 6 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 >=3sigma 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.
Keywords
Cite
@article{arxiv.0912.0386,
title = {Observation of TeV Gamma Rays from the Fermi Bright Galactic Sources with the Tibet Air Shower Array},
author = {M. Amenomori and X. J. Bi and D. Chen and S. W. Cui and Danzengluobu and L. K. Ding and X. H. Ding and C. Fan and C. F. Feng and Zhaoyang Feng and Z. Y. Feng and X. Y. Gao and Q. X. Geng and Q. B. Gou and H. W. Guo and H. H. He and M. He and K. Hibino and N. Hotta and Haibing Hu and H. B. Hu and J. Huang and Q. Huang and H. Y. Jia and L. Jiang and F. Kajino and K. Kasahara and Y. Katayose and C. Kato and K. Kawata and Labaciren and G. M. Le and A. F. Li and H. C. Li and J. Y. Li and C. Liu and Y. -Q. Lou and H. Lu and X. R. Meng and K. Mizutani and J. Mu and K. Munakata and H. Nanjo and M. Nishizawa and M. Ohnishi and I. Ohta and S. Ozawa and T. Saito and T. Y. Saito and M. Sakata and T. K. Sako and M. Shibata and A. Shiomi and T. Shirai and H. Sugimoto and M. Takita and Y. H. Tan and N. Tateyama and S. Torii and H. Tsuchiya and S. Udo and B. Wang and H. Wang and Y. Wang and Y. G. Wang and H. R. Wu and L. Xue and Y. Yamamoto and C. T. Yan and X. C. Yang and S. Yasue and Z. H. Ye and G. C. Yu and A. F. Yuan and T. Yuda and H. M. Zhang and J. L. Zhang and N. J. Zhang and X. Y. Zhang and Y. Zhang and Yi Zhang and Ying Zhang and Zhaxisangzhu and X. X. Zhou},
journal= {arXiv preprint arXiv:0912.0386},
year = {2015}
}
Comments
17 pages, 2 figures, 1 table, Accepted for publication in ApJ Letters