Speaker
Description
The origin of the diffuse neutrino and $\gamma$-ray backgrounds remains uncertain, with galaxy clusters hosting AGN considered promising contributors. We investigate the diffuse $\gamma$-ray and neutrino emission from the Virgo, Perseus, and Coma clusters using a self-consistent framework that combines three-dimensional magnetohydrodynamic (MHD) simulations with Monte Carlo modeling of cosmic-ray (CR) propagation in the intracluster medium (ICM). The MHD simulations provide realistic gas and magnetic-field distributions, which serve as inputs for CR transport and secondary particle production.
Our predicted $\gamma$-ray fluxes from individual clusters are significantly below existing LHAASO upper limits. The MAGIC flux from NGC1275 in Perseus significantly exceeds our diffuse predictions, indicating dominant AGN emission. The cumulative emission from clusters of mass range $\gtrsim 10^{14}\,M_{\odot}$ within 500 Mpc remains below the Fermi-LAT diffuse background. Our neutrino predictions are consistent with IceCube’s upper limits for unresolved cluster emission up to $z=2$.