Related papers: The beamed jet and quasar core of the distant blaz…

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…

We present the jet kinematics of the flat spectrum radio quasar (FSRQ) 4C +21.35 using time-resolved KaVA very long baseline interferometry array radio maps obtained from September 2014 to July 2016. During two out of three observing…

Ground-space interferometer RadioAstron provides unique opportunity to probe detail structure of the distant active galactic nuclei at $\mu$as scales. Here we report on RadioAstron observations of the BL Lac object S5 0716$+$71, performed…

In spring 2005 the blazar 3C 454.3 was observed in an unprecedented bright state from the near-IR to the hard X-ray frequencies. A mm outburst peaked in June-July 2005, and it was followed by a flux increase at high radio frequencies. In…

We present a detailed analysis of the best-quality multi-wavelength data gathered for the large-scale jet in the core-dominated quasar 3C 273. We analyze all the archival observations of the target with the Chandra X-ray Observatory, the…

In 2007-2008 we carried out a new multiwavelength campaign of the Whole Earth Blazar Telescope (WEBT) on BL Lacertae, involving three pointings by the XMM-Newton satellite, to study its emission properties. The source was monitored in the…

Context. 3C 454.3 is a very active flat spectrum radio quasar (blazar) that has undergone a recent outburst in all observed bands, including the optical. Aims. In this work we explore the short-term optical variability of 3C 454.3 during…

Within the blazar population, hard X-ray selected objects are of particular interest as they tend to lie at each end of the blazar sequence. In particular, flat spectrum radio quasars located at high redshifts display the most powerful…

A recent Chandra observation of the nearby galaxy cluster Abell 585 has led to the discovery of an extended X-ray jet associated with the high-redshift background quasar B3 0727+409, a luminous radio source at redshift z=2.5. This is one of…

PBC J2333.9-2343 is a giant radio galaxy at z = 0.047 with a bright central core associated to a blazar nucleus. If the nuclear blazar jet is a new phase of the jet activity, then the small orientation angle suggest a dramatic change of the…

The two-component broad-band spectral energy distributions of blazars were suggested to form a sequence in which (1) the peak frequency of the low-energy (synchrotron) component nu_syn is anticorrelated with the synchrotron luminosity…

Recently, blazar 4C +27.50 was found to be flaring in gamma-rays since its detection with Fermi-LAT in 2008. For the first time, a dedicated temporal and spectral study of the blazar 4C +27.50 has been performed in this work to understand…

The infrared properties of blazars can be studied from the statistical point of view with the help of sky surveys, like that provided by the Wide-field Infrared Survey Explorer (WISE) and the Two Micron All Sky Survey (2MASS). However,…

3C 273 is an intensively monitored flat-spectrum radio quasar with both a beamed jet and blue bump together with broad emission lines. The coexistence of the comparably prominent jet and accretion disk leads to complicated variability…

We have performed infrared imaging of the jet of the quasar 3C 273 at wavelengths 3.6 and 5.8 microns with the Infrared Array Camera (IRAC) on the Spitzer Space Telescope. When combined with the radio, optical and X-ray measurements, the…

High-resolution observations of high-redshift ($z>4$) radio quasars offer a unique insight into jet kinematics at early cosmological epochs, as well as constraints on cosmological model parameters. Due to the general weakness of extremely…

PKS 0537-441, a bright gamma-ray emitting blazar, was observed at radio, optical, UV and X-ray frequencies during various EGRET pointings, often quasi-simultaneously. In 1995 the object was found in an intense emission state at all…

The spectra of blazars form a sequence which can be parametrized in term of their observed bolometric luminosity. At the most powerful extreme of the sequence we find objects whose jet power can rival the power extracted by accretion, while…

The classification of gamma-ray-detected blazar candidates of uncertain type (BCU) is a relevant problem in extragalactic gamma-ray astronomy. Here we report the optical spectroscopic characterization, using two 3-4~m class telescopes,…

The Fermi and Swift satellites, together with ground based Cherenkov telescopes, has greatly improved our knowledge of blazars, namely Flat Spectrum Radio Quasars and BL Lac objects, since all but the most powerful emit most of their…