  Recently, several telescopes, including Swift-BAT, GBM, and LHAASO, have
observed the ever highest-energy and long-duration gamma-rays from a gamma-ray
burst named as GRB221009A (located at a red-shift of $z=0.151$) on October 9,
2022. Conventional understanding tells us that very high-energy photons
produced at such a far distance suffer severe attenuation before reaching the
Earth. We propose the existence of a sub-MeV to $O(10)$ MeV heavy neutrino with
a transitional magnetic dipole moment, via which the heavy neutrino is produced
at the GRB. It then travels a long distance to our galaxy and decays into a
neutrino and a photon, which is observed. In such a way, the original
high-energy photon produced at the GRB can survive long-distance attenuation.
