Axion-photon conversion of GRB221009A

The newly observed gamma ray burst GRB221009A exhibits the existence of 10~TeV-scale photons, and the axion-photon conversion has been suggested as a candidate to explain such energetic features of GRB221009A. In this work we adopt a model to calculate the conversion probability of the energetic photons from GRB221009A to the Earth. The result shows that the penetration probability of photons with energy above $10^1$~TeV can be up to $10^{-2}-10^{-4}$ depending on the coupling constant $g_{a\gamma}$ and the axion mass $m_a$, together with the magnetic field parameters of the host galaxy of GRB221009A. By comparing the results in this article with the data from LHAASO, we can obtain more precise constraints on the ranges of these parameters.