on behalf of the Fermi-LAT collaboration
Axion-like particles (ALPs) occur in a variety of extensions of the Standard Model and constitute a viable candidate for dark matter. They could be detected through their coupling to photons in magnetic fields. In astrophysical targets like galaxy clusters, this coupling would lead to a reduction of the photon flux and oscillations in the energy spectra of astrophysical sources around a specific critical energy. We report on the search for ALP-induced spectral irregularities in the gamma-ray spectrum of NGC 1275, the central radio galaxy of the Perseus galaxy cluster, using six years of data taken with the Large Area Telescope (LAT) on board the Fermi satellite. Astrophysical sources located in galaxy clusters are in general promising candidates for ALP searches as these systems harbor strong magnetic fields over large spatial scales. In our analysis, we make use of the Pass 8 event reconstruction of Fermi-LAT data. We do not find evidence for ALPs and set limits that surpass or are comparable to other constraints from astrophysical and laboratory searches between 5 and 20 neV, and are competitive with the sensitivity of future experiments. Together with other bounds, our limits strongly constrain the parameter space where ALPs could explain hints for a reduced opacity for gamma rays in the Universe.