The Large High Altitude Air Shower Observatory(LHAASO)has reported the detection of a large number of multi-Te V-scale photon events also including several Pe V-scale gamma-ray-photon events with energy as high as 1.4 Pe V.The possibility that some of these events may have extragalactic origins is not yet excluded.Here we propose a mechanism for the traveling of very-high-energy and ultra-high-energy photons based upon the axionphoton conversion scenario,which allows extragalactic above-threshold photons to be detected by observers on the Earth.We show that the axion-photon conversation can serve as an alternative mechanism,besides the threshold anomaly due to Lorentz invariance violation,for the very-high-energy features of the newly observed gamma ray burst GRB 221009A.
展开▼
