Improved Constraints on Dark Matter Annihilation to a Line using Fermi-LAT observations of Galaxy Clusters

Understand

Galaxy clusters are dominated by dark matter, and may have a larger proportion of surviving substructure than, e.g, field galaxies.

• Due to the presence of galaxy clusters in relative proximity and their high dark matter content, they are promising targets for the indirect detection of dark matter via Gamma-rays.
• Indeed, dedicated studies of sets of up to 100 clusters have been made previously, so far with no clear indication of a dark matter signal.
• Here we report on Gamma-ray observations of some 26,000 galaxy clusters based on Pass-7 Fermi Large Area Telescope (LAT) data, with clusters selected from the Tully 2MASS Groups catalog.