First Detection of Ultrahigh Energy Emission from Gamma-Ray Binary LS I +61° 303
1
Issued Date
2026-05-08
Resource Type
ISSN
00319007
eISSN
10797114
Scopus ID
2-s2.0-105039181254
Journal Title
Physical Review Letters
Volume
136
Issue
18
Rights Holder(s)
SCOPUS
Bibliographic Citation
Physical Review Letters Vol.136 No.18 (2026)
Suggested Citation
Cao Z., Aharonian F., Bai Y.X., Bao Y.W., Bastieri D., Bi X.J., Bi Y.J., Bian W., Bukevich A.V., Cai C.M., Cao W.Y., Cao Z., Chang J., Chang J.F., Chen A.M., Chen E.S., Chen G.H., Chen H.X., Chen L., Chen L., Chen M.J., Chen M.L., Chen Q.H., Chen S., Chen S.H., Chen S.Z., Chen T.L., Chen X.B., Chen X.J., Chen Y., Cheng N., Cheng Y.D., Chu M.C., Cui M.Y., Cui S.W., Cui X.H., Cui Y.D., Dai B.Z., Dai H.L., Dai Z.G., Danzengluobu, Diao Y.X., Dong X.Q., Duan K.K., Fan J.H., Fan Y.Z., Fang J., Fang J.H., Fang K., Feng C.F., Feng H., Feng L., Feng S.H., Feng X.T., Feng Y., Feng Y.L., Gabici S., Gao B., Gao C.D., Gao Q., Gao W., Gao W.K., Ge M.M., Ge T.T., Geng L.S., Giacinti G., Gong G.H., Gou Q.B., Gu M.H., Guo F.L., Guo J., Guo X.L., Guo Y.Q., Guo Y.Y., Han Y.A., Hannuksela O.A., Hasan M., He H.H., He H.N., He J.Y., He X.Y., He Y., Hernández-Cadena S., Hou B.W., Hou C., Hou X., Hu H.B., Hu S.C., Huang C., Huang D.H., Huang J.J., Huang T.Q., Huang W.J., Huang X.T., Huang X.Y., Huang Y., Huang Y.Y., Ji X.L., Jia H.Y., Jia K. First Detection of Ultrahigh Energy Emission from Gamma-Ray Binary LS I +61° 303. Physical Review Letters Vol.136 No.18 (2026). doi:10.1103/7xhp-tff7 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/116842
Title
First Detection of Ultrahigh Energy Emission from Gamma-Ray Binary LS I +61° 303
Author(s)
Cao Z.
Aharonian F.
Bai Y.X.
Bao Y.W.
Bastieri D.
Bi X.J.
Bi Y.J.
Bian W.
Bukevich A.V.
Cai C.M.
Cao W.Y.
Cao Z.
Chang J.
Chang J.F.
Chen A.M.
Chen E.S.
Chen G.H.
Chen H.X.
Chen L.
Chen L.
Chen M.J.
Chen M.L.
Chen Q.H.
Chen S.
Chen S.H.
Chen S.Z.
Chen T.L.
Chen X.B.
Chen X.J.
Chen Y.
Cheng N.
Cheng Y.D.
Chu M.C.
Cui M.Y.
Cui S.W.
Cui X.H.
Cui Y.D.
Dai B.Z.
Dai H.L.
Dai Z.G.
Danzengluobu
Diao Y.X.
Dong X.Q.
Duan K.K.
Fan J.H.
Fan Y.Z.
Fang J.
Fang J.H.
Fang K.
Feng C.F.
Feng H.
Feng L.
Feng S.H.
Feng X.T.
Feng Y.
Feng Y.L.
Gabici S.
Gao B.
Gao C.D.
Gao Q.
Gao W.
Gao W.K.
Ge M.M.
Ge T.T.
Geng L.S.
Giacinti G.
Gong G.H.
Gou Q.B.
Gu M.H.
Guo F.L.
Guo J.
Guo X.L.
Guo Y.Q.
Guo Y.Y.
Han Y.A.
Hannuksela O.A.
Hasan M.
He H.H.
He H.N.
He J.Y.
He X.Y.
He Y.
Hernández-Cadena S.
Hou B.W.
Hou C.
Hou X.
Hu H.B.
Hu S.C.
Huang C.
Huang D.H.
Huang J.J.
Huang T.Q.
Huang W.J.
Huang X.T.
Huang X.Y.
Huang Y.
Huang Y.Y.
Ji X.L.
Jia H.Y.
Jia K.
Aharonian F.
Bai Y.X.
Bao Y.W.
Bastieri D.
Bi X.J.
Bi Y.J.
Bian W.
Bukevich A.V.
Cai C.M.
Cao W.Y.
Cao Z.
Chang J.
Chang J.F.
Chen A.M.
Chen E.S.
Chen G.H.
Chen H.X.
Chen L.
Chen L.
Chen M.J.
Chen M.L.
Chen Q.H.
Chen S.
Chen S.H.
Chen S.Z.
Chen T.L.
Chen X.B.
Chen X.J.
Chen Y.
Cheng N.
Cheng Y.D.
Chu M.C.
Cui M.Y.
Cui S.W.
Cui X.H.
Cui Y.D.
Dai B.Z.
Dai H.L.
Dai Z.G.
Danzengluobu
Diao Y.X.
Dong X.Q.
Duan K.K.
Fan J.H.
Fan Y.Z.
Fang J.
Fang J.H.
Fang K.
Feng C.F.
Feng H.
Feng L.
Feng S.H.
Feng X.T.
Feng Y.
Feng Y.L.
Gabici S.
Gao B.
Gao C.D.
Gao Q.
Gao W.
Gao W.K.
Ge M.M.
Ge T.T.
Geng L.S.
Giacinti G.
Gong G.H.
Gou Q.B.
Gu M.H.
Guo F.L.
Guo J.
Guo X.L.
Guo Y.Q.
Guo Y.Y.
Han Y.A.
Hannuksela O.A.
Hasan M.
He H.H.
He H.N.
He J.Y.
He X.Y.
He Y.
Hernández-Cadena S.
Hou B.W.
Hou C.
Hou X.
Hu H.B.
Hu S.C.
Huang C.
Huang D.H.
Huang J.J.
Huang T.Q.
Huang W.J.
Huang X.T.
Huang X.Y.
Huang Y.
Huang Y.Y.
Ji X.L.
Jia H.Y.
Jia K.
Author's Affiliation
University of Chinese Academy of Sciences
Tsinghua University
Shanghai Jiao Tong University
Sun Yat-Sen University
Université Paris Cité
University of Science and Technology of China
Shandong University
Nanjing University
Chinese University of Hong Kong
Zhengzhou University
Southwest Jiaotong University
Yunnan University
Guangzhou University
Institute of High Energy Physics, Chinese Academy of Sciences
National Astronomical Observatories Chinese Academy of Sciences
Hebei Normal University
Max-Planck-Institut für Kernphysik
Institute for Nuclear Research of the Russian Academy of Sciences
Yerevan State University
China Center of Advanced Science and Technology World Laboratory
Zhejiang Lab
Purple Mountain Observatory Chinese Academy of Sciences
Shanghai Astronomical Observatory Chinese Academy of Sciences
Yunnan Observatories
Tibet University
State Key Laboratory of Particle Detection & Electronics
TIANFU Cosmic Ray Research Center
Tsinghua University
Shanghai Jiao Tong University
Sun Yat-Sen University
Université Paris Cité
University of Science and Technology of China
Shandong University
Nanjing University
Chinese University of Hong Kong
Zhengzhou University
Southwest Jiaotong University
Yunnan University
Guangzhou University
Institute of High Energy Physics, Chinese Academy of Sciences
National Astronomical Observatories Chinese Academy of Sciences
Hebei Normal University
Max-Planck-Institut für Kernphysik
Institute for Nuclear Research of the Russian Academy of Sciences
Yerevan State University
China Center of Advanced Science and Technology World Laboratory
Zhejiang Lab
Purple Mountain Observatory Chinese Academy of Sciences
Shanghai Astronomical Observatory Chinese Academy of Sciences
Yunnan Observatories
Tibet University
State Key Laboratory of Particle Detection & Electronics
TIANFU Cosmic Ray Research Center
Corresponding Author(s)
Other Contributor(s)
Abstract
We report the first detection of gamma-ray emission up to ultrahigh-energy (UHE; >100 TeV) emission from the prototypical gamma-ray binary system LS I +61° 303 using data from the Large High Altitude Air Shower Observatory. It is detected with significances of 9.2σ in the Water Cherenkov Detector Array (WCDA, 1.4-30.5 TeV) and 6.2σ in the Kilometer Square Array (KM2A, 25-267 TeV); in KM2A alone we identify 16 photonlike events above 100 TeV against an estimated 5.1 background events, corresponding to a 3.8σ detection. These results provide compelling evidence of extreme particle acceleration in LS I +61° 303. Furthermore, we observe orbital modulation at 3.9σ confidence level, between 25 and 100 TeV, with a hint that the orbital modulation is energy dependent. These features can be understood in a composite scenario in which leptonic and hadronic processes jointly contribute.