Vovk, Ie.Korochkin, A.Neronov, AndriiSemikoz, D.2024-05-012024-05-012024-05-012024-02-2910.1051/0004-6361/202347310https://infoscience.epfl.ch/handle/20.500.14299/207615WOS:001185001700011Delayed 'pair-echo' signal from interactions of very-high-energy gamma rays in the intergalactic medium can be used for the detection of the intergalactic magnetic field (IGMF). We used the data of the Fermi/LAT telescope coupled with LHAASO observatory measurements to confirm the presence of IGMF along the line of sight to the gamma-ray burst GRB 221009A. Comparing the Fermi/LAT measurements with the expected level of the pair-echo flux, set by the multi-TeV LHAASO detection, we derived a lower bound 10(-19) G on the IGMF with correlation length l larger than 1 Mpc, improving as l(-1/2) for shorter correlation lengths. This provides an independent verification of the existence of a lower bound on IGMF in the voids of the large-scale structure, previously derived from the observations of active galactic nuclei.Physical SciencesGamma-Ray Burst: Individual: Grb 221009AIntergalactic MediumGamma Rays: Generaltext::journal::journal article::research article