What determines the observational differences of blazars?

TL;DR

This study investigates how the Doppler factor influences observed differences in blazars, revealing intrinsic relations and challenging previous correlations after accounting for Doppler boosting.

Contribution

It demonstrates that intrinsic properties of blazars are better correlated with the Doppler factor and black hole mass, refining understanding of blazar observational diversity.

Findings

Negative correlation between observed peak frequency and Doppler factor.

Intrinsic peak frequency linearly relates to Doppler factor after correction.

Blazar sequence disappears after Doppler boosting correction.

Abstract

We examine the scenario that the Doppler factor determines the observational differences of blazars in this paper. Significantly negative correlations are found between the observational synchrotron peak frequency and the Doppler factor. After correcting the Doppler boosting, the intrinsic peak frequency further has a tightly linear relation with the Doppler factor. It is more interesting that this relation is consistent with the scenario that the black hole mass governs both the bulk Lorentz factor and the synchrotron peak frequency. In addition, the distinction of the kinetic jet powers between BL Lacs and FSRQs disappears after the boosting factor $\delta^2$ is considered. The negative correlation between the peak frequency and the observational isotropic luminosity, known as the blazar sequence, also disappears after the Doppler boosting is corrected. We also find that the correlation between the Compton dominance and the Doppler factor exists for all types of blazars. Therefore, this correlation is unsuitable to examine the external Compton emission dominance.