An ultrahigh-energy [formula omitted]-ray bubble powered by a super PeVatron

Z Cao,X.P Zhang,N Cheng,H.J Mu,Y He,S.H Feng,L Zhao,N Yin,Axikegu Axikegu,X.T Feng,J.L Liu,H.R Wu,Z.Y Pei,Y.S Wu,Yu.V Stenkin,D.M Wei,Jie Li,X.X Zhou,L.S Geng,B Gao,Y.L Xin,Y.H Yao,W Mitthumsiri,Y.F Liang,D Li,C.F Feng,B.B Zhang,Y Xing,P.H Wang,C Hou,X.L Guo,F Zheng,Y.K Hor,Y.H Yu,W.J Huang,B.B Li,Yi Zhang,Lin Chen,B Liu,X.L Ji,K Jia,H.B Hu,H.C Song,J.N Zhou,P.F Zhang,L Shao,C.Y Shao,M.Y Cui,Cheng Li,T Wen,Y.C Nan,L.P Wang,J.L Zhang,J.C Wang,Z.G Yao,J.Y Liu,M.L Chen,S.W Cui,Zhen Wang,Cong Li,R Lu,Z.B Tang,B.Z Dai,J Zhao,X Hou,J Liu,B.W Hou,S.J Lin,E.S Chen,X.F Wu,J.F Chang,M Jin,P.P Zhang,S.P Zhao,W.Y Cao,H Zhu,H.L Dai,J.H Fan,Q Luo,S.M Liu,H.H He,C.B Wang,Y.D Wang,Z.W Ou,Long Chen,R.Z Yang,Y.Q Guo,D Liu,B.Q Qiao,J Li,V Stepanov,M.J Chen,X.J Bi,Y.J Bi,H.Y Zhang,X.Y Huang,T Ke,J Chang,O Shchegolev,X.H Cui,D Semikoz,Y.J Wei,Y.X Bai,R.Y Liu,A Sáiz,Q.W Tang,Zhe Li,Zhe Cao,Y.M Ye,C.G Zhu,R Zhou,X Zhang,Z.H Wang,K.K Duan,C.Y Wu,Y.Z Li,H.Y Jia,G.W Wang,H.G Wang,Y.Q Qi,H.H Wang,H Yue,Y.Z Fan,Y.J Wang,Q.N Sun,Q Cao,F Zhang,C Liu,S.S Zhang,Y Su,L.Q Yin,Z.B Sun,Y Wang,J.R Mao,F.R Zhu,Li Zhang,J.T Cai,D Della Volpe,R.F Xu,L.X Zhang,Q Hu,R Wang,M Zha,L Xue,H Liu,J.Y Yang,Y.Y Guo,G Giacinti,Xin Li,Y.W Bao,J.J Wei,X.R Li,Y.L Feng,K Fang,W.W Tian,H.W Yang,X.W Jiang,Q Gao,D.H Yan,Q.B Gou,E.W Liang,L.Z Zhao,G.H Gong,Z.G Dai,F Li,S.B Yang,Z Min,A Neronov,X Zuo,X.B He,Y Liu,Y.N Liu,X.D Sheng,M Zhou,S.B Zhang,B.Q Ma,W Zeng,H.K Lv,J Fang,K Li,D.H Huang,Y.D Cui,J.Y He,J.J Qin,C.D Gao,F Aharonian,Zhuo Li,K.J Zhu,Y Chen,H.B Li,Y.D Cheng,R Zhang,W Wang,M.M Ge,Jian Li,X.H You,D Bastieri,D.L Xu,Danzengluobu Danzengluobu,F.F Yang,X.G Wang,W Gao,K Wang,J.Z Yan,L.L Ma,P.H.T Tam,Yong Zhang,X.H Ma,D.X Xiao,M.Y Liu,Z.C Huang,W Liu,S.R Zhang,H.M Zhang,P Zhou,Z.J Jiang,D Kuleshov,L.Q Gao,Z.Y You,X.T Huang,B Zhao,C Wang,B Zhou,S.C Hu,J Xia,F.L Guo,D Ruffolo,P Pattarakijwanich,Z.X Wang,Q.H Chen,X.Q Dong,G.M Xiang,Liang Chen,M.H Gu,H.D Zeng,Zheng Wang,K Jiang,Q An,B.Y Pang,H Zhou,M.M Kang,L.L Yang,Q Yuan,W.L Xu,H.Y Li,S Gabici,J.J Xia,H.N He,G.G Xin,R.X Xu,M Heller,W.L Li,T Yan,T.X Zeng,S.H Chen,Y.F Zhang,Z Xiong,X.N Sun,L Feng,Y Huang,Y.A Han,C.W Yang,T.Q Huang,W.K Gao,G Xiao,F.W Shu,X.Y Wang,H.D Liu,A.M Chen,H.C Li,S.Q Xi,L.Y Wang,S.Z Chen,M.J Yang,S Wu,K Kurinov,T.L Chen,M.Y Qi,F Yang

doi:10.1016/j.scib.2023.12.040

Abstract

We report the detection of a γ-ray bubble spanning at least 100deg2 in ultra-high energy (UHE) up to a few PeV in the direction of the star-forming region Cygnus X, implying the presence super PeVatron(s) accelerating protons to at least 10 PeV. A log-parabola form with the photon index Γ(E)=(2.71±0.02)+(0.11±0.02)×log10(E/10TeV) is found fitting the gamma-ray energy spectrum of the bubble well. UHE sources, “hot spots” correlated with very massive molecular clouds, and a quasi-spherical amorphous γ-ray emitter with a sharp central brightening are observed in the bubble. In the core of ∼0.5°, spatially associating with a region containing massive OB association (Cygnus OB2) and a microquasar (Cygnus X-3), as well as previously reported multi-TeV sources, an enhanced concentration of UHE γ-rays is observed with 2 photons at energies above 1 PeV. The general feature of the bubble, the morphology, and the energy spectrum, are reasonably reproduced by the assumption of a particle accelerator in the core, continuously injecting protons into the ambient medium.

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