Related papers: Infrared Variation of Blazars
For a new sample of 8 weak-line-quasars (WLQs) we report a sensitive search in 20 intranight monitoring sessions, for blazar-like optical flux variations on hour-like and longer time scale (day/month/year$-$like). The sample consists…
We collect the 2LAC and MOJAVE quasi-simultaneous data to investigate the radio-gamma connection of blazars. The cross sample contains 166 sources. The statistic analysis based on this sample confirms positive correlations between these two…
Due to the first results on astrophysical X-ray polarization provided by \textit{IXPE} observatory, the interest in wavelength-dependent synchrotron polarization of BL Lac type objects increases. This paper presents the results of…
Observations of very high energy gamma-rays from blazars provide information about acceleration mechanisms occurring in their innermost regions. Studies of variability in these objects allow a better understanding of the mechanisms at play.…
In this work, we report the presence of rapid intra-night optical variations in both -- flux and polarization of the blazar BL Lacertae during its unprecedented 2020--2021 high state of brightness. The object showed significant flux…
The BL Lacertae object PKS 2155-304 was observed by the Infrared Space Observatory in May and June 1996, during a multiwavelength campaign. These are the first observations in the mid- and far-infrared bands since IRAS. In the observing…
The phenomenology of gamma-ray bright blazars can be accounted for by a sequence in the source power and intensity of the diffuse radiation field surrounding the relativistic jet. Correspondingly, the equilibrium particle distribution peaks…
We compare the variability properties of very high energy gamma-ray emitting BL Lac objects in the optical and radio bands. We use the variability information to distinguish multiple emission components in the jet, to be used as a guidance…
We present $\gamma$-ray, X-ray, ultraviolet, optical, and near-infrared light curves of 33 $\gamma$-ray bright blazars over four years that we have been monitoring since 2008 August with multiple optical, ground-based telescopes and the…
The current status of leptonic jet models for 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 regime.…
Gamma-ray emitting blazars have been the targets of many recent or ongoing monitoring programmes. The resulting multi-wavelength data archives are ideal for studying the quiescent and variable behaviour of the blazar PKS 2155-304. Here,…
The blazars 3C 454.3, PKS 0537-441 and PKS 2155-304 are traditionally known to be among the most active sources of this class. They emit at all frequencies, up to the gamma-rays, and are good probes of multiwavelength nuclear variability.…
We have observed with ROSAT six blazars from the sample of 31 polarized objects constructed by Impey and Tapia (1988). Results of the spectral analysis in the ROSAT band of three objects, PKS 0301-243, PKS 1055+018 and PG 1424+240 are…
We select a sample of 10 radio-quiet quasars with confirmed intranight optical variability and with available X-ray data. We compare the variability properties and the broad band spectral constraints to the predictions of intranight…
Multiwavelength polarimetry is a powerful tool to probe magnetic field and flow geometries in the relativistic jets of blazars. In this respect, particularly interesting are the sources whose synchrotron emission covers a broad range of…
We present the results of the optical monitoring of 18 southern blazars in the V and R Johnson-Cousins bands. Our main objective is to study the variations in the optical flux and theis relationship with the colour and spectral…
We present the results of a near-infrared monitoring programme of a selected sample of stars, initially suspected to be Mira variables and OH/IR stars, covering more than a decade of observations. The objects monitored cover the typical…
The variation mechanism of blazars is a long standing open question. The polarization observation can provide us with more information to constrain models. In this work, we collect the long term multi-wavelength data of AO 0235+164, and…
Blazars are an extreme subclass of active galactic nuclei. Their rapid variability, luminous brightness, superluminal motion, and high and variable polarization are probably due to a beaming effect. However, this beaming factor (or Doppler…
In this work, we present the results of our multi-band microvariability study of the famous blazar BL Lac. We performed microvariablity observations of the source in the optical VRI bands for 4 nights in the year 2016. We studied the…