{"paper":{"title":"An optical spectroscopic survey of the 3CR sample of radio galaxies with z<0.3. IV. Discovery of the new spectroscopic class of relic radio galaxies","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.CO","authors_text":"3) David J. Axon (4, 3) Marco Chiaberge (6, 5) Andrew Robinson (5) Annalisa Celotti (3) Ranieri D. Baldi (1, 7) F. Duccio Macchetto (6) William B. Sparks (6) ((1) INAF - Osservatorio Astronomico di Torino, Alessandro Capetti (1) Sara Buttiglione (2, Baltimore, Bologna, Italy), Italy (2) INAF - Osservatorio Astronomico di Padova, Italy (3) SISSA-ISAS, Italy (4) University of Sussex, Trieste, UK (5) Rochester Institute of Technology, USA (6) Space Telescope Science Institute, U.S.A. (7) INAF-Istituto di Radio Astronomia","submitted_at":"2011-01-10T11:55:37Z","abstract_excerpt":"From an optical spectroscopic survey of 3CR radio galaxies with z<0.3, we discovered a new spectroscopic class of powerful radio-loud AGN. The defining characteristics of these galaxies are that compared with radio galaxies of similar radio luminosity they have: a [O III]\\Hb ratio of ~0.5, indicative of an extremely low level of gas excitation; a large deficit of [O III] emission and radio core power. We interpret these objects as relic AGN, i.e. sources that experienced a large drop in their level of nuclear activity, causing a decrease in their nuclear and line luminosity. This class opens a"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1101.1787","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}