Moderate Correlation between the Accretion Disk and Jet Power in a Large Sample of Fermi Blazars

TL;DR

This study analyzes the relationship between accretion disk and jet power in Fermi-detected blazars, revealing a moderate intrinsic correlation after accounting for redshift effects, and suggesting that high disk power is necessary but not sufficient for powerful jets.

Contribution

It provides a comprehensive analysis of disk-jet power correlation in a large blazar sample, accounting for redshift bias and revealing nuanced insights into their relationship.

Findings

Significant correlation between disk and jet power indicators.

Redshift bias influences observed correlations.

High disk power is necessary but not sufficient for high jet power.

Abstract

We present the results of studying the accretion disk vs jet power for a large fraction of all the blazars detected by the Fermi Gamma-Ray Space Telescope. The disk power is inferred from the emission line luminosities obtained from published results. As indicators of jet power, we use low frequency radio luminosity from the extended jet, maximum speed of radio knots observed in the VLBA monitoring of the pc-scale jets, kinetic energy of electrons in the jet deduced from the best-fit theoretical models of their spectral energy distribution, and gamma-ray luminosity with and without beaming correction. We obtain a significant correlation in most of those cases. However, we find that the correlations are often driven by the common redshift dependence of the compared quantities. In order to remove the redshift bias and probe the intrinsic correlation between the disk and jet power, we compute the partial correlation coefficient as well as the correlation in small redshift bins, and find that the intrinsic disk-jet correlation is still present but weaker. In the cases, in which the common redshift dependence does not affect the result, we find that blazars do not exhibit high jet power for low disk luminosities while there are both high and low jet power for high disk luminosities. This result indicates that a powerful disk is a necessary but not sufficient condition to produce a powerful jet.