Correlations between radio emission of the parsec-scale jet and optical nuclear emission of host AGN

TL;DR

This study investigates the relationship between radio and optical emissions in AGN jets, revealing significant correlations that support the beaming model and localized emission regions in the innermost jet areas.

Contribution

It provides new evidence of correlated radio and optical emissions in a large AGN sample, confirming the emission origin and beaming effects in parsec-scale jets.

Findings

Strong correlation between optical and radio emissions in quasars.

Correlation between optical and radio emissions in BL Lacs.

Results support beaming and localized emission regions in jets.

Abstract

We study the relation between the VLBA (Very Long Baseline Array) radio emission at 15 GHz and the optical nuclear emission at 5100 A for a sample of 233 core-dominated AGN with relativistic jets. For 181 quasars, there is a significant positive correlation between optical nuclear emission and total radio (VLBA) emission of unresolved cores (on milliarcsecond scales) of the jet at 15 GHz. Optical continuum emission correlates with radio emission of the jet for 31 BL Lacs. These correlations confirm that the radio and optical emission are beamed and originate at sub-parsec scales in the innermost part of the jet in quasars, while they are generated in the parsec-scale jet in BL Lacs. These results are in agreement with that reported earlier by Arshakian et al. 2010 for a sample of 135 AGN.