Radio and spectroscopic properties of miniature radio galaxies: revealing the bulk of the radio-loud AGN population
We explore radio and spectroscopic properties of a sample of 14 miniature radio galaxies, i.e. early-type core galaxies hosting radio-loud AGN of extremely low radio power, 1027-29 erg s-1 Hz-1 at 1.4 GHz. Miniature radio galaxies smoothly extend the relationships found for the more powerful FR I ra...
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Published in | Astronomy and astrophysics (Berlin) Vol. 508; no. 2; pp. 603 - 614 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
Les Ulis
EDP Sciences
01.12.2009
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Subjects | |
Online Access | Get full text |
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Summary: | We explore radio and spectroscopic properties of a sample of 14 miniature radio galaxies, i.e. early-type core galaxies hosting radio-loud AGN of extremely low radio power, 1027-29 erg s-1 Hz-1 at 1.4 GHz.
Miniature radio galaxies smoothly extend the relationships found for the more powerful FR I radio galaxies between emission line, optical and radio nuclear luminosities to lower levels. However, they have a deficit of a factor of ~100 in extended radio emission with respect to that of the classical example of 3CR/FR I. This is not due to their low luminosity, since we found radio galaxies of higher radio core power, similar to those of 3CR/FR I, showing the same behavior, i.e. lacking significant extended radio emission. Such sources form the bulk of the population of radio-loud AGN in the Sloan Digital Sky Survey. At a given level of nuclear emission, one can find radio sources with an extremely wide range, a factor of $\ga$100, of radio power.
We argue that the prevalence of sources with luminous extended radio structures in flux limited samples is due to a selection bias, since the inclusion of such objects is highly favored. The most studied catalogues of radio galaxies are thus composed by the minority of radio-loud AGN that meet the physical conditions required to form extended radio sources, while the bulk of the population is virtually unexplored. |
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Bibliography: | publisher-ID:aa13021-09 istex:EA5F3BEAC02A3130E34FA7328EA9800089F2831D other:2009A%26A...508..603B Based on observations made with the Italian Telescopio Nazionale Galileo operated on the island of La Palma by the Centro Galileo Galilei of INAF (Istituto Nazionale di Astrofisica) at the Spanish Observatorio del Roque del los Muchachos of the Instituto de Astrofisica de Canarias. ark:/67375/80W-J0N6CCHL-2 ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
ISSN: | 0004-6361 1432-0746 |
DOI: | 10.1051/0004-6361/200913021 |