|VOLUME 116 (2022) | ISSUE 11 |
Parameters of axion-like particles required to explain high-energy photons from GRB 221009A
S. V. Troitsky
Institute for Nuclear Research of the Russian Academy of Sciences, 117312 Moscow, Russia
Recent astrophysical transient Swift J1913.1+1946 is possibly associated
with the gamma-ray burst GRB 221009A at the redshift .
The transient was accompanied by very high-energy gamma rays up to 18 TeV
observed by LHAASO and a photon-like air shower of 251 TeV detected by
Carpet-2. These energetic gamma rays cannot reach us from the claimed
distance of the source because of the pair production on cosmic
background radiation. If the identification and redshift measurements are
correct, one would require new physics to explain the data. One
possibility invokes axion-like particles (ALPs) which mix with photons
but do not attenuate on the background radiation. Here we explore the ALP
parameter space and find that the ALP-photon mixing in the Milky Way,
and not in the intergalactic space, may help to explain the observations.
However, given the low Galactic latitude of the event, misidentification
with a Galactic transient remains an undiscarded explanation.