The correlations of multi-wave band luminosity and BLR luminosity in Fermi 2LAC blazars

TL;DR

This study analyzes correlations between multi-wave band luminosities and BLR luminosity in 78 Fermi-detected blazars, supporting jet-disk symbiosis and revealing different emission mechanisms across bands.

Contribution

It provides the first comprehensive analysis of multi-band luminosity correlations in Fermi blazars, highlighting the different origins of X-ray and gamma-ray emissions.

Findings

Significant correlations between radio, gamma-ray, and BLR luminosities.

X-ray emission likely from synchrotron self-Compton process.

Gamma-ray emission likely from external Compton process.

Abstract

We collect a sample of 78 Fermi detected blazars with broad line region (BLR) data and the quasi-simultaneous multi-wave band data. By analyzing the sample, we find: (1) For whole blazar sample, there exist significant correlations between radio, $\gamma$-ray luminosity and BLR luminosity. The slope of the best-fit linear regression equation is close to the theoretical value 1. Our results provided another support of jet-disk symbiosis. (2) For FSRQ sample, we find a significant correlation between radio luminosity and optical luminosity, and weaker correlations between X-ray luminosity and radio, optical luminosity. It indicates that the X-ray band radiation mechanism is slightly different from radio and optical bands. The X-ray emission is diluted by inverse Compton scattering (IC). There is a significant correlation between BLR luminosity and $\gamma$-ray luminosity, but no correlations between X-ray luminosity and BLR, $\gamma$-ray luminosity, which suggests that the seed soft photons are different for IC process. From these results we suggest that the X-ray band emission is diluted by synchrotron self-Compton (SSC) process, $\gamma$-ray band emission is produced by external Compton (EC) process.