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arXiv · 1101.1787

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

Alessandro Capetti·Sara Buttiglione·David J. Axon·Andrew Robinson·Annalisa Celotti·Ranieri D. Baldi·Marco Chiaberge·F. Duccio Macchetto·William B. Sparks
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Abstract

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 novel approach to investigating lifetimes and duty cycles of AGN.

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Alessandro Capetti, Sara Buttiglione, David J. Axon, Andrew Robinson, Annalisa Celotti, Ranieri D. Baldi, Marco Chiaberge, F. Duccio Macchetto, William B. Sparks. 2011-01-10. 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. https://doi.org/10.1051/0004-6361/201016026

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