Related papers: Optical intraday variability analysis for the BL L…
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…
BL Lacertae is not only archetypical of an entire class of jet-dominated active galactic nuclei, blazars, but also one of the most active and rapidly changing objects in this class. In the fall of 2024 (September--November), BL Lacertae…
The typical blazar S5 0716$+$714 is very interesting due to its rapid and large amplitude variability and high duty cycle of micro-variability in optical band. We analyze the observations in I, R and V bands obtained with the $1.0m$…
In this paper, we report results of our near-infrared (NIR) photometric variability studies of the BL Lacertae object S5 0716+714. NIR photometric observations spread over 7 nights during our observing run April 2-9, 2007 at 1.8 meter…
We present time series analyses of three-decade long radio observations of the BL Lacertae object AO 0235+164 made at the University of Michigan Radio Astronomical Observatory operating at three central frequencies of 4.8 GHz, 8.0 GHz and…
We monitored BL Lacertae in the B, V, R and I bands for 14 nights during the period of 2016-2018. The source showed significant intraday variability on 12 nights. We performed colour-magnitude analysis and found that the source exhibited…
We investigate the possible presence of quasi-periodic oscillation (QPO) signals in 2103 blazars from the Zwicky Transient Facility (ZTF) time-domain survey. We detect a low-frequency QPO signal in five blazars observed over these…
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 Lacertae over a wide wavelength range: with the…
Based on the Zwicky Transient Facility (ZTF), we selected 10 blazars as our sample sources. Among these, we found four blazars (J 0923.5+4125, J 1221.3+3010, J 1503.5+4759, and J 1652.7+4024) showing possible indications of quasi periodic…
Context. The international whole earth blazar telescope (WEBT) consortium planned and carried out three days of intensive micro-variability observations of S5 0716+714 from February 22, 2009 to February 25, 2009. This object was chosen due…
Context. We present the light curves of six BL Lac objects, PKS 0537-441, PKS 0735+17, OJ 287, PKS 2005-489, PKS 2155-304, W Comae, and of the flat spectrum radio quasar PKS 1510-089, as a part of a photometric monitoring program in the…
We report the first extensive optical flux and spectral variability study of the TeV blazar TXS 0506+056 on intra-night to long-term timescales using BVRI data collected over 220 nights between January 21, 2017 to April 9, 2022 using 8…
We conducted a comprehensive variability analysis of the blazar PKS 2255-282 using Fermi-LAT observations spanning over four years, from MJD 57783.5 to 59358.5. Our analysis revealed a transient quasi-periodic oscillation (QPO) with a…
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,…
Blazars exhibit variable emission on diverse timescales. Some light curves show signs of quasiperiodic oscillations (QPOs), which may encode clues regarding the physical processes behind the emission or point to supermassive binary black…
We present results of a multi-epoch intra-night optical monitoring of eleven blazars consisting of six BL Lac objects and five radio core-dominated quasars (CDQs). These densely sampled and sensitive R-band CCD observations, carried out…
We report the results of our optical (VRI) photometric observations of the TeV blazar 1ES 0806$+$524 on 153 nights during 2011-2019 using seven optical telescopes in Europe and Asia. We investigated the variability of the blazar on intraday…
We present the result of our extensive intranight optical monitoring of the well known low-energy peaked BL Lac (LBL) object PKS 0735+178. This long-term follow-up consists of $R$-band monitoring for a minimum duration of $\sim 4$ hours, on…
We withdraw our claim that a component in an XMM-Newton satellite light curve of the BL Lacertae object S5 0716 + 714 shows quasi-periodic oscillations (QPOs) of $\sim$30 minutes. Although both our original periodogram and wavelet analyses…
We report the first results obtained from our campaign to characterize the intranight-optical variability (INOV) properties of {\it Fermi}~detected blazars, using the observations from the recently commissioned 1.3 m J C Bhattacharya…