Year: 2026
Type: preprint
Abstract: While compact steep-spectrum (CSS) radio galaxies, genuine young/intermittent-jet or frustrated-jet radio galaxies trapped in gas-rich environments, are rarely detected in GeV gamma-ray energy bands, 3C 216 is an interesting exception. In 2023, the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope detected an unexpected, rapid, and powerful GeV gamma-ray outburst from this CSS radio galaxy, which was followed up by UV and X-ray observations from the Neil Gehrels Swift Space Observatory. During the outburst its spectral energy distribution is dominated by synchrotron and synchrotron self-Compton radiation, produced in the relativistic jet, suggesting a young quasar classification. Radio-band features, such as superluminal motion and a flat-spectrum core component, confirm that 3C 216 harbors a distinct blazar-like core, bent and viewed under a small angle to the line of sight. This is the unique large and energetic event from the source observed in 17 years of Fermi-LAT continuous all-sky and time-domain monitoring.
Source: arXiv (Cornell University)
Authors: Ciprini, Stefano, Giacchino, Federica
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: U.S. Department of Energy, National Aeronautics and Space Administration, Ministry of Education, Culture, Sports, Science and Technology, Centre National d’Etudes Spatiales, Vetenskapsrådet, Centre National de la Recherche Scientifique, Japan Aerospace Exploration Agency, Institut National de Physique Nucléaire et de Physique des Particules
OpenAlex ID: W7214805812