Curvature of the spectral energy distribution, the dominant process for inverse Compton component and other jet properties in Fermi 2LAC blazars

TL;DR

This study analyzes the spectral energy distributions of Fermi 2LAC blazars, revealing how their spectral curvature relates to acceleration mechanisms and jet properties, and confirming different emission processes for BL Lacs and FSRQs.

Contribution

It provides new empirical correlations between spectral features, luminosities, and jet parameters, clarifying the dominant inverse Compton processes and jet origins in blazars.

Findings

Linear correlation between synchrotron peak frequency and curvature for BL Lacs and FSRQs.

IC luminosity correlates with synchrotron luminosity, consistent with EC and SSC processes.

Significant correlations between IC curvature and black hole mass, jet Lorentz factor, and broad line luminosity.

Abstract

We fit the spectral energy distributions (SEDs) of members of a large sample of Fermi 2LAC blazars to synchrotron and inverse Compton (IC) models. Our main results are as follows. (i) As suggested by previous works, the correlation between peak frequency and curvature can be explained by statistical or stochastic particle acceleration mechanisms. For BL Lacs, we find a linear correlation between synchrotron peak frequency and its curvature. The slope of the correlation is consistent with the stochastic acceleration mechanisms and confirm previous studies. For FSRQs, we also find a linear correlation, but its slope cannot be explained by previous theoretical models. (ii) We find a significant correlation between IC luminosity and synchrotron luminosity. The slope of the correlation of FSRQs is consistent with the EC process. And the slope of the correlation of BL Lac is consistent with the SSC process. (iii) We find several significant correlations between IC curvature and several basic parameters of blazars (black hole mass, broad line luminosity, the Lorentz factor of jet). We also find significant correlations between bolometric luminosity and these basic parameters of blazars which suggest that the origin of jet is a mixture of the mechanisms proposed by Blandford $\&$ Znajek and by Blandford $\&$ Payne.