Spectral Energy Distribution variation in BL Lacs and FSRQs

TL;DR

This study analyzes the spectral energy distributions of ten blazars, revealing that variations are primarily driven by changes in jet Doppler factors, with SEDs well-modeled by log-parabolic electron energy distributions.

Contribution

It provides the first detailed analysis linking SED variations in blazars to changes in jet Doppler factors using log-parabolic models.

Findings

Strong correlation between spectral parameters a and b

Negative trend between peak frequency and spectral curvature

Jet Doppler factor changes are key to SED variability

Abstract

We present the results of our study of spectral energy distributions (SEDs) of a sample of ten low- to intermediate-synchrotron-peaked blazars. We investigate some of the physical parameters most likely responsible for the observed short-term variations in blazars. To do so, we focus on the study of changes in the SEDs of blazars corresponding to changes in their respective optical fluxes. We model the observed spectra of blazars from radio to optical frequencies using a synchrotron model that entails a log-parabolic distribution of electron energies. A significant correlation among the two fitted spectral parameters ($a$, $b$) of log-parabolic curves and a negative trend among the peak frequency and spectral curvature parameter, $b$, emphasize that the SEDs of blazars are fitted well by log-parabolic curves. On considering each model parameter that could be responsible for changes in the observed SEDs of these blazars, we find that changes in the jet Doppler factors are most important.