Radio core dominance of Fermi/LAT-detected AGNs Virtual Observatory Resource

Authors
  1. Pei Z-Y.
  2. Fan J.-H.
  3. Bastieri D.
  4. Yang J.-H.
  5. Xiao H.-B.
  6. Published by
    CDS
Abstract

We present a sample of 4388 AGNs with available radio core-dominance parameters-defined as the ratio of the core flux densities to the extended ones, R=S_core_/S_ext._ - which includes 630 Fermi-detected AGNs from the fourth source catalog (4FGL) of the Fermi Large Area Telescope (Fermi/LAT); the rest are non-Fermi-detected AGNs. In our sample, 584 blazars are Fermi-detected and 1310 are not. The sample also contains other subclasses, such as Seyferts, Fanaroff-Riley I/II galaxies, and normal galaxies. We investigate various properties of the Fermi-detected and non-Fermi-detected AGNs by using core-dominance parameters, capitalizing on a previous study which showed that R is a good indicator of beaming. We then calculate radio spectral indices for the whole sample, and adopt {gamma}-ray-photon indices for the Fermi AGNs from the 4FGL catalog to discuss the properties of different subclasses. We obtain a relation between the core-dominance parameters and the radio spectral indices for both Fermi and non-Fermi sources, assuming a two-component model in the radio band. Our previous study ruled out the assumption that the core-dominance parameters and radio spectral indices are quite different for different AGN subclasses. This holds not only for Fermi sources but also for non-Fermi sources. In particular, R is, on average, greater for the former AGNs than for the latter. In this study, we enlarge our sample with available values of R to 4388 AGNs, and the obtained conclusions are consistent with our previous study. We assume that the same two-component model holds for the {gamma}-ray band as for the radio band, and therefore, adopt the same relation between the core-dominance parameters and the {gamma}-ray-photon indices for Fermi AGNs. Our fitting results indicate that the {gamma}-ray emissions of Fermi blazars originate mainly from the jet, and therefore, we conclude that the Fermi blazars are beamed.

Keywords
  1. Active galactic nuclei
  2. Quasars
  3. Gamma-ray astronomy
Bibliographic source Bibcode
2020SCPMA..63y9511P
See also HTML
https://cdsarc.cds.unistra.fr/viz-bin/cat/VIII/108
IVOA Identifier IVOID
ivo://CDS.VizieR/VIII/108
Document Object Identifer DOI
bibcode:2020yCat.8108....0P

Access

Web browser access HTML
http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=VIII/108
https://vizier.iucaa.in/viz-bin/VizieR-2?-source=VIII/108
http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=VIII/108
IVOA Table Access TAP
http://tapvizier.cds.unistra.fr/TAPVizieR/tap
Run SQL-like queries with TAP-enabled clients (e.g., TOPCAT).

History

2020-10-19T11:04:59Z
Resource record created
2020-10-19T11:04:59Z
Created
2021-01-11T08:49:05Z
Updated

Contact

Name
CDS support team
Postal Address
CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France
E-Mail
cds-question@unistra.fr