相关论文: Uncovering the physics behind the blazar sequence …
Blazars are the brightest and most abundant persistent sources in the extragalactic gamma-ray sky. Due to their significance, they are often observed across various energy bands to explore potential correlations between emissions at…
We analyze the parsec-scale jet kinematics from 2007 June to 2013 January of a sample of $\gamma$-ray bright blazars monitored roughly monthly with the Very Long Baseline Array at 43~GHz. In a total of 1929 images, we measure apparent…
We report the variation of the spectral energy distribution (SED) of blazars as a function of source activity, based on available, simultaneous multi-wavelength (MWL) observations of BL Lac objects. We use a fully automatized \c{hi}2…
Blazars are thought to emit highly-collimated outflows, so-called jets. By their close alignment to our line of sight, relativistic beaming effects enable us to observe these jets over the whole electromagnetic spectrum up to TeV energies,…
Blazars are a sub-category of radio-loud active galactic nuclei with relativistic jets pointing towards the observer. They exhibit non-thermal variable emission, which practically extends over the whole electromagnetic spectrum. Despite the…
Blazars are a class of active galactic nuclei which host relativistic jets oriented close to the observer's line of sight. Blazars have very complex variability properties. Flares, namely flux variations around the mean value with a…
For a sample of 51 blazars with extensive optical polarization data, we used circular statistics to calculate the scatter among the polarization position angles for each object. We found that this scatter is correlated with the radio core…
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…
Context: Understanding the acceleration mechanism of astrophysical jets has been a cumbersome endeavor from both the theoretical and observational perspective. Although several breakthroughs have been achieved in recent years, on all sides,…
Blazars - active galaxies with the jet pointing at Earth - emit across all electromagnetic wavelengths. The so-called one-zone model has described well both quiescent and flaring states, however it cannot explain the radio emission. In…
We consider particle acceleration to high energy via diffusive shock acceleration in a simple, self-consistent shock in jet model for blazars. Electrons are assumed to be accelerated at a shock front in relativistic jets and radiate…
The BL Lacertae (BL Lac) object OJ 287 is one of the most dynamic blazars across the directly accessible observational windows: spectral, timing, polarization, and imaging. Apart from behaviors considered characteristics of blazars, it…
Blazar subclasses ranging from flat-spectrum radio quasars (FSRQs) through low-frequency-peaked BL Lac objects (LBLs) to high-frequency-peaked BL Lac objects (HBLs) exhibit a sequence of increasing spectral hardness with decreasing…
Mildly-relativistic shocks that are embedded in colliding magnetohydrodynamic flows are prime sites for relativistic particle acceleration and production of strongly variable, polarized multi-wavelength emission from relativistic jet…
Electrons emitting non-thermal photons in blazars are possibly accelerated by turbulences developed in jets. In this paper, we consider the case so-called hard-sphere scattering as an interaction model between turbulences and electrons, in…
In a two-component jet model, the emissions are the sum of the core and extended emissions: $S^{\rm ob}=S_{\rm core}^{\rm ob}+S_{\rm ext}^{\rm ob}$, with the core emissions, $S_{\rm core}^{\rm ob}= f S_{\rm ext}^{\rm ob}\delta^{q}$, being a…
The current status of leptonic jet models for gamma-ray blazars is reviewed. Differences between the quasar and BL-Lac subclasses of blazars may be understood in terms of the dominance of different radiation mechanisms in the gamma-ray…
The extreme variability of blazars, in both timescale and amplitude, is generally explained as the effect of a relativistic jet closely aligned to the observer's line-of-sight. Due to causality arguments, variability characteristics…
Blazars display strong variability on multiple timescales and in multiple radiation bands. Their variability is often characterized by power spectral densities (PSDs) and time lags plotted as functions of the Fourier frequency. We develop a…
Our understanding of the unification of jetted AGN has evolved greatly as jet samples have increased in size. Here, based on the largest-ever sample of over 2000 well-sampled jet spectral energy distributions, we examine the synchrotron…