Axionlike particle limits from multimessenger sources

High-energy neutrino observation from the Seyfert galaxy NGC 1068 offers new insights into the nonthermal processes of active galactic nuclei. Simultaneous γ rays emitted by such sources can possibly oscillate into axionlike particles (ALPs) when propagating through astrophysical magnetic fields, potentially modifying the observed spectrum. To probe for ALP-induced signals, a robust understanding of the emission processes at the source is necessary. In this work, we perform a dedicated multimessenger analysis by modeling a jet in the innermost vicinity of the central supermassive black hole of NGC 1068. We model in particular the neutrino and γ -ray emission originating in lepto-hadronic collisions between jet accelerated particles and background particles from the corona, reproducing both the Fermi-LAT and IceCube data. These source models serve as a baseline for ALP searches, and we derive limits on the ALP-photon coupling by marginalizing over motivated ranges of astrophysical parameters. We find g a γ ≲ 7 × 10 − 11 GeV − 1 for m a ≲ 10 − 9 eV . These limits may be weaker than existing constraints, but they demonstrate the potential of multimessenger observations to probe new physics. We conclude by discussing how additional upcoming multimessenger sources and improved observational precision can enhance ALP sensitivity.