Description
Jets from active galactic nuclei (AGNs) are promising candidates for the acceleration of ultra-high-energy cosmic rays (UHECRs). If AGN jets are indeed dominant sources, the diffuse UHECR flux should trace the underlying jet power and, by extension, reflect the nature of supermassive black hole (SMBH) accretion states. In this work, we employ the cosmological semi-analytic framework JET (Jets from Early Times), which models jet production and feedback while distinguishing between accretion modes based on SMBH Eddington ratios. Using JET, we investigate how the diffuse UHECR flux at the source evolves with jet production efficiency and different SMBH accretion models over cosmic time, from redshift z=20 to z=1. This study connects large-scale cosmological models of SMBH evolution with high-energy astroparticle backgrounds. We also discuss implications for the diffuse neutrino background associated with AGN populations, offering insights into the multi-messenger signatures of SMBH activity throughout the Universe’s history.
