From the Fermi blazar sequence to the relation between Fermi blazars and gamma-ray Narrow-line Seyfert 1 Galaxies

TL;DR

This study analyzes Fermi blazars and gamma-ray Narrow-line Seyfert 1 Galaxies to explore their spectral properties, beaming effects, and acceleration mechanisms, revealing insights into the blazar sequence and jet physics.

Contribution

It provides new observational evidence on the blazar sequence, the impact of beaming, and the acceleration processes in gamma-NLSy1s compared to other blazars.

Findings

Weak anti-correlation between synchrotron peak frequency and luminosity supports the blazar sequence.

Doppler correction removes the inverse correlation, indicating beaming effects influence the observed relation.

Gamma-NLSy1s fit well into the original blazar sequence based on jet power and spectral properties.

Abstract

We use the third catalog of blazars detected by Fermi/LAT (3LAC) and gamma-ray Narrow-line Seyfert 1 Galaxies (gamma-NLSy1s) to study the blazar sequence and relationship between them. Our results are as follows: (i) There is a weak anti-correlation between synchrotron peak frequency and peak luminosity for both Fermi blazars and gamma-NLSy1s, which supports the blazar sequence. However, after Doppler correction, the inverse correlation disappeared, which suggests that anti-correlation between synchrotron peak frequency and peak luminosity is affected by the beaming effect. (ii) There is a significant anti-correlation between jet kinetic power and synchrotron peak frequency for both Fermi blazars and gamma-NLSy1s, which suggests that the gamma-NLSy1s could fit well into the original blazar sequence. (iii) According to previous work, the relationship between synchrotron peak frequency and synchrotron curvature can be explained by statistical or stochastic acceleration mechanisms. There are significant correlations between synchrotron peak frequency and synchrotron curvature for whole sample, Fermi blazars and BL Lacs, respectively. The slopes of the correlation are consistent with statistical acceleration. For FSRQs, LBLs, IBLs, HBLs, and gamma-NLS1s, we also find a significant correlation, but in these cases the slopes can not be explained by previous theoretical models. (iv) The slope of relation between synchrotron peak frequency and synchrotron curvature in gamma-NLS1s is large than that of FSRQs and BL Lacs. This result may imply that the cooling dominates over the acceleration process for FSRQs and BL Lacs, while gamma-NLS1s is the opposite.