Related papers: BVI Microvariability in BL LAC during the summer 1…

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…

We monitored the BL Lac object S5 0716+714 in the optical band during October 2008, December 2008 and February 2009 with a best temporal resolution of about 5 minutes in the BVRI bands. Four fast flares were observed with amplitudes ranging…

We have observed S4 0954+658 in the BVRI bands in 2001, and in the BI bands in 2002. The observations resulted in almost evenly sampled light curves, 3-8 hours long, with an average sampling interval of ~5-15 min. Because of the dense…

We monitored BL Lacertae frequently during 2014 - 2016 when it was generally in a high state. We searched for intra-day variability for 43 nights using quasi-simultaneous measurements in the B, V, R, and I bands (totaling 143 light curves);…

In this presentation, we report the results of intraday variability in the optical (BVRI bands) and hard X-ray band (3-79 keV) in a number of blazars. In the optical microvariability studies of the blazars S5 0716+714 and BL Lac, we…

We report results based on the monitoring of the BL Lac object Mrk 501 in the optical (B, V and R) passbands from March to May 2000. Observations spread over 12 nights were carried out using 1.2 meter Mount Abu Telescope, India and 61 cm…

The aim of our observations is to investigate the intranight variability properties and the spectral variability of BL Lacertae. 799 optical multi-band observations were intensively made with the Beijing-Arizona-Taiwan-Connecticut (BATC)…

We have observed BL Lacertae in the B, R and I bands for 2 nights in July, 1999, and 3 nights in July, 2001. The observations resulted in almost evenly sampled light curves, with an average sampling interval of ~5 min. The source is…

With an aim to explore optical variability at diverse timescales in BL Lac source S5 0716+714, it was observed for 46 nights during 2013 January 14 to 2015 June 01 when it underwent two major outbursts. The observations were made using the…

We present the results of our optical monitoring of the BL Lac object S5 0716+714 on seven nights in 2006 December. The monitoring was carried out simultaneously at three optical wavelengths with a novel photometric system. The object did…

We monitored BL Lacertae simultaneously in the optical B, V, R and I bands for 13 nights during the period 2012-2016. The variations were well correlated in all bands and the source showed significant intraday variability (IDV). We also…

Optical monitoring of S5 0716+714 was performed with a 60/90 Schmidt telescope in 2003 November and December and 2004 January for studying the variability of the object on short timescales. Due to the high brightness of the source we could…

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 perform quasi-simultaneous optical multi-band monitoring of BL Lac object S5 0716+714 on seven nights from 2013 to 2016. Intra-day variability (IDV) is found on all seven nights. The source was faintest on JD 2456322 with 14.15 mags and…

During 2001-2002 the optically violent variable (OVV) blazar 3C 279 un- derwent the most intense outburst seen during the entire fourteen year history that this quasar has been studied at Colgate University's Foggy Bottom Obser- vatory…

We present the analysis results of flux and spectral variability of the blazar OP 313 across intra-night to short-term timescales using BVRI photometric data, gathered over 25 nights from Nov 2024 to May 2025, using two optical telescopes…

We have monitored the BL Lacertae object S5 0716+714 in the optical bands during 2012 January and February with long time spans on intraday timescales ($>$5 hr) and high time resolutions. During this monitoring period, the object shows…

We present results of two-colour photometry with high time resolution of the violently variable BL Lac object AO 0235+164. We have found extreme intranight variability with amplitudes of ~ 100 % over time scales of 24 hours. Changes of 0.5…

We have carried out optical (R band) intraday variability (IDV) monitoring of a sample of ten bright low energy peaked blazars (LBLs). Forty photometric observations, of an average of ~ 4 hours each, were made between 2008 September and…

We report results from a 1 week multi-wavelength campaign to monitor the BL Lac object S5 0716+714 (on December 9-16, 2009). In the radio bands the source shows rapid (~ (0.5-1.5) day) intra-day variability with peak amplitudes of up to ~…