2026/06/16 by Nobuyuki Sakai, Yoshiyuki Inoue, Ellis R. Owen
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Dark Matter and Cosmic Phenomena #Gamma-ray bursts and supernovae
paper · pdf · doi:10.3847/1538-4357/ae7d28
Abstract The origin of the cosmic neutrino background (CNB) and the cosmic gamma-ray background (CGB) remains uncertain. Accretion disk winds driven by active galactic nuclei (AGNs) have been proposed as possible contributors, but their predicted background levels depend sensitively on poorly constrained wind energetics and ambient densities. We revisit the AGN disk-wind scenario by constructing a lepto-hadronic wind model calibrated with radio and GeV gamma-ray data of nearby Fermi Large Area Telescope–detected Seyfert galaxies. In our framework, cosmic rays accelerated both at wind-driven forward and reverse shocks produce synchrotron, external-Compton, and hadronic emission. We also incorporate recent XRISM constraints on wind parameters. Applying our calibrated lepto-hadronic models to an AGN population synthesis model, we find that disk winds contribute at most ≲5% of the CGB above 10 GeV and ≲10% of the CNB around 100 TeV, suggesting that they are unlikely to dominate both backgrounds. Finally, we identify nearby Seyfert galaxies hosting ultrafast outflows as promising targets for future TeV gamma-ray and TeV–PeV neutrino observations, which would offer firm tests of the disk-wind scenario.