Pair-Matching of Radio-Loud and Radio-Quiet AGNs

Frontiers in Astronomy and Space Sciences

Vale Asari, Natalia¹  Kozieł-Wierzbowska, Dorota²  jtowicz, Anna³  Sikora, Marek³  Stasińska, Grażyna⁴  Wó⁵  Goettems, Elisa⁶ 

[1] Paris Diderot, France;Astronomical Observatory, Jagiellonian University, Poland;Departamento de FíLUTH, Observatoire de Paris, Centre National de la Recherche Scientifique, UniversitéNicolaus Copernicus Astronomical Center, Poland;sica–CFM, Universidade Federal de Santa Catarina, Brazil

关键词: active galaxies;    radio galaxies;    jetted and non-jetted AGNs;    radio-loudness;    Galaxy morphology;   

DOI  :  10.3389/fspas.2017.00039

学科分类：空间科学

来源: Frontiers

【 摘 要 】

Active galactic nuclei (AGNs) are known to cover an extremely broad range of radio luminosities and the spread of their radio-loudness is very large at any value of the Eddington ratio. This implies very diverse jet production efficiencies which can result from the spread of the black hole spins and magnetic fluxes. Magnetic fluxes can be developed stochastically in the innermost zones of accretion discs, or can be advected to the central regions prior to the AGN phase. In the latter case \rev{there could be} systematic differences between the properties of galaxies hosting radio-loud (RL) and radio-quiet (RQ) AGNs. In the former case the differences should be negligible for objects having the same Eddington ratio. To study the problem we decided to conduct a comparison study of host galaxy properties of RL and RQ AGNs. In this study we selected type II AGNs from SDSS spectroscopic catalogues. Our RL AGN sample consists of the AGNs appearing in the \citet{Best.Heckman.2012a} catalogue of radio galaxies. To compare RL and RQ galaxies that have the same AGN parameters we matched the galaxies in black hole mass, Eddington ratio and redshift. We compared several properties of the host galaxies in these two groups of objects like galaxy mass, colour, concentration index, line widths, morphological type and interaction signatures. We found that in the studied group RL AGNs are preferentially hosted by elliptical galaxies while RQ ones are hosted by galaxies of earlier type. We also found that the fraction of interacting galaxies is the same in both groups of AGNs. These results suggest that the magnetic flux in RL AGNs is advected to the nucleus prior to the AGN phase.

【 授权许可】

CC BY