Zhang Y.He J.Zhang R.Zhao S.Cao Z.Aharonian F.An Q.AxikeguBai Y.X.Bao Y.W.Bastieri D.Bi X.J.Bi Y.J.Cai J.T.Cao Q.Cao W.Y.Cao Z.Chang J.Chang J.F.Chen A.M.Chen E.S.Chen L.Chen L.Chen L.Chen M.J.Chen M.L.Chen Q.H.Chen S.H.Chen S.Z.Chen T.L.Chen Y.Cheng N.Cheng Y.D.Cui M.Y.Cui S.W.Cui X.H.Cui Y.D.Dai B.Z.Dai H.L.Dai Z.G.Danzengluobudella Volpe D.Dong X.Q.Duan K.K.Fan J.H.Fan Y.Z.Fang J.Fang K.Feng C.F.Feng L.Feng S.H.Feng X.T.Feng Y.L.Gabici S.Gao B.Gao C.D.Gao L.Q.Gao Q.Gao W.Gao W.K.Ge M.M.Geng L.S.Giacinti G.Gong G.H.Gou Q.B.Gu M.H.Guo F.L.Guo X.L.Guo Y.Q.Guo Y.Y.Han Y.A.He H.H.He H.N.He J.Y.He X.B.He Y.Heller M.Hor Y.K.Hou B.W.Hou C.Hou X.Hu H.B.Hu Q.Hu S.C.Huang D.H.Huang T.Q.Huang W.J.Huang X.T.Huang X.Y.Huang Y.Huang Z.C.Ji X.L.Jia H.Y.Jia K.Jiang K.Jiang X.W.Jiang Z.J.Jin M.Kang M.M.Ke T.Mahidol University2024-12-232024-12-232024-09-27Proceedings of Science Vol.444 (2024)https://repository.li.mahidol.ac.th/handle/20.500.14594/102494We analyze gamma-ray emission from the Northern Fermi bubble region at the ultra-high-energy range, using the data collected by LHAASO-KM2A from December 2019 to September 2022. Employing an improved gamma/hadron separation method, the median energy of the gamma rays is above 25 TeV. We perform the “direct integral method” in the background estimation; however, no significant excess is observed. Consequently, we present the expected upper limits for gamma-ray emissions within the Fermi bubble region at this energy range.MultidisciplinaryConference PaperSCOPUS2-s2.0-8518561049918248039