Related papers: Multiwavelength intraday variability: what do the …

Studying the periodic flux-variation behavior of blazars is vital for probing supermassive black hole binaries and the kinematics of relativistic jets. In this work, we report the detection of the multi-band possible periodic variations of…

We selected a sample of a dozen blazars which are the prime candidates for simultaneous multi-wavelength observing campaigns in their outburst phase. We searched for optical outbursts, intra-day variability and short term variability in…

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…

We attempt to present a multiwavelength variability and correlation study as well as detailed multi-waveband spectral characteristics of the May 2021 $\gamma$-ray flare of the blazar source TXS 1700+685. The multi-wavelength observation…

We have monitored the BL Lacertae object S5 0716+714 simultaneously in the B, R and I bands on three nights in November 2014. The average time resolution is quite high (73s, 34s, 58s for the filters B, R and I), which can help us trace the…

Using data from the Wide-field Infrared Survey Explorer we studied the mid infrared 3.4 $\mu$m (W1-band) and 4.6 $\mu$m (W2-band) flux variability of $\gamma$-ray emitting blazars. Our sample consists of 460 flat spectrum radio quasars…

The analysis of $\gamma$-ray flux variability along with the parsec-scale jet kinematics suggests that the high-energy radiation in the BL Lac object S5 0716+714 has a significant correlation with the mm-VLBI core flux density and with the…

In 2022 the BL Lac object S4 0954+65 underwent a major variability phase, reaching its historical maximum brightness in the optical and $\gamma$-ray bands. We present optical photometric and polarimetric data acquired by the Whole Earth…

Our recent progress on time-dependent modeling of the multiwavelength spectra and variability of blazars with leptonic and hadronic jet models is reviewed. Special emphasis is placed on X-ray spectral variability of low-frequency peaked…

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…

Blazars are the established sources of an intense and variable non-thermal radiation extending from radio wavelengths up to HE and VHE gamma-rays. Understanding the spectral evolution of blazars in selected frequency ranges, as well as…

We discuss the implications of rapid (few-minute) variability in the TeV flux of blazars, which has been observed recently with the HESS and MAGIC telescopes. The variability timescales seen in PKS 2155-304 and Mrk 501 are much shorter than…

We present the timing analysis of 10 archived \XMM observations with an exposure of $>40$ ks of Markarian 421. Mrk 421 is the brightest high-frequency-peaked BL Lac object (HBL) emitting in X-rays produced by electrons accelerated in the…

We present the results of our power spectral analysis for the BL Lac object PKS 0735+178 utilizing the Fermi-LAT survey at high-energy $\gamma$-rays, several ground-based optical telescopes, and single-dish radio telescopes operating at GHz…

In May 1994 the BL Lac object PKS 2155-304 was observed continuously for ~10 d with IUE and EUVE and for 2 d with ASCA, as well as with ROSAT and with ground- based radio, IR, and optical telescopes. The light curves show a well-defined…

The occurrence of low-amplitude flux variations in blazars on hourly timescales, commonly known as microvariability, is still a widely debated subject in high-energy astrophysics. Several competing scenarios have been proposed to explain…

Aims. We aim to investigate the extreme variability properties of the TeV blazar S4 0954+65 using optical photometric and polarisation observations carried out between 2017 and 2023 using three ground-based telescopes. Methods. We examined…

We report rapid optical variability for the blazar S5 0716+71 during 2010 March 08-10 & 19-20 in the CCD observations made from Mt.Abu Infrared Observatory. The light curves are constructed for the duration longer than 3-hours each night,…

The blazar 3C 454.3 was revealed by the Fermi Gamma-ray Space Telescope to be in an exceptionally high flux state in July 2008. Accordingly, we performed a multi-wavelength monitoring campaign on this blazar using IR and optical…

The bright radio source S5 0716+714, that is usually classified as BL Lac object, is one of the most intensively studied. S5 0716+714 demonstrates extremely peculiar properties such as the shortest time-scale of optical and polarimetric…