BL Lac objects are active nuclei, hosted in massive elliptical galaxies, the emission of which
is dominated by a relativistic jet closely aligned with the line of sight. This implies the …

We describe new implementations of leptonic and hadronic models for the broadband
emission from relativistic jets in active galactic nuclei in a temporary steady state. For the …

Blazars are active galactic nuclei (AGN) with relativistic jets whose non-thermal radiation is
extremely variable on various timescales,–. This variability seems mostly random, although …

Blazars are the most violent steady/recurrent sources of high-energy gamma-ray emission in
the known Universe. They are prominent emitters of electromagnetic radiation throughout …

Eight optical and four radio observatories have been intensively monitoring the BL Lac
object 0716+ 714 in the last years: 4854 data points have been collected in the UBVRI …

We report on the correlation between the flux, color, and polarization variations on time
scales of days–months in blazars, and discuss their universal aspects. We performed …

ABSTRACT Blazar S5 0716+ 714 is well-known for its short-term variability, down to intraday
time-scales. We here present the 2-min cadence optical light curve obtained by the TESS …

Since the launch of the Fermi satellite, BL Lacertae has been moderately active at γ-rays
and optical frequencies until 2011 May, when the source started a series of strong flares …

In an effort to locate the sites of emission at different frequencies and physical processes
causing variability in blazar jets, we have obtained high time-resolution observations of BL …

Context. The quasar 3C 279 is among the most extreme blazars in terms of luminosity and
variability of flux at all wavebands. Its variations in flux and polarization are quite complex …