Cao Z.Aharonian F.AxikeguBai Y.X.Bao Y.W.Bastieri D.Bi X.J.Bi Y.J.Bian W.Bukevich A.V.Cao Q.Cao W.Y.Cao Z.Chang J.Chang J.F.Chen A.M.Chen E.S.Chen H.X.Chen L.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 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.DanzengluobuDong 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 Y.Hor Y.K.Hou B.W.Hou C.Hou X.Hu H.B.Hu Q.Hu S.C.Huang C.Huang D.H.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.Jiang H.B.Jiang K.Jiang X.W.Mahidol University2025-06-082025-06-082025-07-01Science China Physics Mechanics and Astronomy Vol.68 No.7 (2025)16747348https://repository.li.mahidol.ac.th/handle/123456789/110570We report a dedicated study of the newly discovered extended UHE γ-ray source 1LHAASO J0056+6346u. Analyzing 979 d of LHAASO-WCDA data and 1389 d of LHAASO-KM2A data, we observed a significant excess of γ-ray events with both WCDA and KM2A. Assuming a point power-law source with a fixed spectral index, the significance maps reveal excesses of 12.65 σ, 22.18 σ, and 10.24 σ in the energy ranges of 1–25, 25–100, and >100 TeV, respectively. We use a 3D likelihood algorithm to derive the morphological and spectral parameters, and the source is detected with significances of 13.72 σ by WCDA and 25.27 σ by KM2A. The best-fit positions derived from WCDA and KM2A data are (R.A. = 13.96° ± 0.09°, Decl. = 63.92° ± 0.05°) and (R.A. = 14.00° ± 0.05°, Decl. = 63.79° ± 0.02°), respectively. The angular size (r<inf>39</inf>) of 1LHAASO J0056+6346u is 0.34° ± 0.04° at 1–25 TeV and 0.24° ± 0.02° at >25 TeV. The differential flux of this UHE γ-ray source can be described by an exponential cutoff power-law function: (2.67 ± 0.25) × 10⁻¹⁵ (E/20 TeV)^{(−1.97±0.10)} e^{−E/(55.1±7.2) TeV} TeV⁻¹ cm⁻² s⁻¹. To explore potential sources of γ-ray emission, we investigated the gas distribution around 1LHAASO J0056+6346u. 1LHAASO J0056+6346u is likely to be a TeV PWN powered by an unknown pulsar, which would naturally explain both its spatial and spectral properties. Another explanation is that this UHE γ-ray source might be associated with gas content illuminated by a nearby CR accelerator, possibly the SNR candidate G124.0+1.4.Physics and AstronomyArticleSCOPUS10.1007/s11433-024-2661-82-s2.0-10500710615218691927