3C 57 as an atypical radio-loud quasar: Implications for the radio-loud/radio-quiet dichotomy

DOI: 
10.1093/mnras/stv710
Publication date: 
21/06/2015
Main author: 
Sulentic J.W.
IAA authors: 
Sulentic J.W.;Martínez-Carballo M.A.;del Olmo A.;Plauchu-Frayn I.
Authors: 
Sulentic J.W., Martínez-Carballo M.A., Marziani P., del Olmo A., Stirpe G.M., Zamfir S., Plauchu-Frayn I.
Journal: 
Monthly Notices of the Royal Astronomical Society
Publication type: 
Article
Volume: 
450
Pages: 
1916-1925
Number: 
Abstract: 
Lobe-dominated radio-loud (LD RL) quasars occupy a restricted domain in the 4D Eigenvector 1 (4DE1) parameter space which implies restricted geometry/physics/kinematics for this subclass compared to the radio-quiet (RQ) majority of quasars. We discuss how this restricted domain for the LD RL parent population supports the notion for a RQ-RL dichotomy among type 1 sources. 3C 57 is an atypical RL quasar that shows both uncertain radio morphology and falls in a region of 4DE1 space where RL quasars are rare. We present new radio flux and optical spectroscopic measures designed to verify its atypical optical/UV spectroscopic behaviour and clarify its radio structure. The former data confirms that 3C 57 falls off the 4DE1 quasar 'main sequence' with both extreme optical Fe II emission (RFe II ~ 1) and a large CIV λ1549 profile blueshift (~-1500 km s-1). These parameter values are typical of extreme Population A sources which are almost always RQ. New radio measures show no evidence for flux change over a 50+year time-scale consistent with compact steep-spectrum (or young LD) over core-dominated morphology. In the 4DE1 context where LD RL are usually low L/L<inf>Edd</inf> quasars, we suggest that 3C 57 is an evolved RL quasar (i.e. large blackhole mass) undergoing a major accretion event leading to a rejuvenation reflected by strong Fe II emission, perhaps indicating significant heavy metal enrichment, high bolometric luminosity for a low-redshift source and resultant unusually high Eddington ratio giving rise to the atypical CIV λ1549. © 2015 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.
Database: 
SCOPUS
WOK
ADS
URL: 
https://ui.adsabs.harvard.edu/#abs/2015MNRAS.450.1916S/abstract
ADS Bibcode: 
2015MNRAS.450.1916S
Keywords: 
Line: profiles; Quasars: emission lines; Quasars: general; Quasars: individual: 3C 57