The long-term multiband optical observations and colour index for the quasar 3C 273

Dai, B. Z.; Li, X. H.; Liu, Z. M.; Zhang, B. K.; Na, W. W.; Wu, Yunfei; Hao, J. M.; Xiang, Yang; Jiang, Z. J.; Zhang, L.

doi:10.1111/j.1365-2966.2008.14137.x

Cited by 56 publications

(29 citation statements)

References 54 publications

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“…An analysis of the optical LC of 3C 273 spanning over 100 yr can be interpreted to suggest a LTV time‐scale of ∼13.5 yr (Fan, Qian & Tao 2001). Recently, the short‐term optical variability and colour index properties of the source have been studied by Dai et al (2009).…”

Section: Analysis and Resultsmentioning

confidence: 99%

“…In one source, 3C 273, we are unable to classify the state of the source since this blazar has been in an essentially steady state for last six yr (Dai et al 2009; Rani et al 2010b). This source showed significant microvariations in two out of eight observed LCs and on both the days of observation the brightness of the source follows both rising and fading trends of ∼0.05 mag.…”

Section: Discussionmentioning

confidence: 99%

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Optical intraday variability studies of 10 low energy peaked blazars

Rani

Gupta

Joshi

et al. 2011

Monthly Notices of the Royal Astronomical Society

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We have carried out optical (R band) intraday variability (IDV) monitoring of a sample of 10 bright low energy peaked blazars (LBLs). 40 photometric observations, of an average of ∼4 h each, were made between 2008 September and 2009 June using two telescopes in India. Measurements with good signal‐to‐noise ratios were typically obtained within 1–3 min, allowing the detection of weak, fast variations using N‐star differential photometry. We employed both structure function and discrete correlation function analysis methods to estimate any dominant time‐scales of variability and found that in most of the cases any such time‐scales were longer than the duration of the observation. The calculated duty cycle of IDV in LBLs during our observing run is ∼52 per cent, which is low compared to many earlier studies; however, the relatively short periods for which each source was observed can probably explain this difference. We briefly discuss possible emission mechanisms for the observed variability.

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Section: Analysis and Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Optical intraday variability studies of 10 low energy peaked blazars

Rani

Gupta

Joshi

et al. 2011

Monthly Notices of the Royal Astronomical Society

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“…Our observations on the variability in S5 0716+714, the bluer when brighter trend and the increase of the amplitude of variability towards shorter wavelengths appear to be more consistent in terms of shocks propagating in the relativistic jet of S5 0716+714. Recently, Dai et al (2009) noted that among blazars, BL Lacs show a bluer when brighter trend whereas FSQSRs show a redder when brighter trend. This might indicate the existence of different physical conditions in these two sub‐classes of blazars.…”

Section: Discussionmentioning

confidence: 99%

Simultaneous MITSuMEg′R_CI_Cmonitoring of S5 0716+714

Stalin¹,

Kawabata²,

Uemura³

et al. 2009

Monthly Notices of the Royal Astronomical Society

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We present the results of our intra‐night optical flux monitoring observations of S5 0716+714 done simultaneously in g′, RC and IC filters. The observations were done using the Multicolor Imaging Telescopes for Survey and Monstrous Explosions instrument on the 50 cm telescope at the Okayama Astrophysical Observatory over 30 nights between 2008 March 11 and 2008 May 8. Of these 30 nights, 22 nights have continuous (without any break) observations with the duration ranging from 1 to 6 h and hence were considered for intra‐night optical variability (INOV). The remaining eight nights have continuous observations of less than 1 h and hence were considered only for long‐term optical variability. In total, we have 4888 data points which were simultaneous in g′, RC and IC filters. Of the 22 nights considered for INOV, the object showed flux variability on 19 nights with the amplitude of variability in the IC band ranging from ∼4 per cent to ∼55 per cent. The duty cycle for INOV was thus found to be 83 per cent. A good correlation between the light curves in all the three bands was found. No time lag between different bands was noticed on most of the nights, except for three nights where the variation in g′ was found to lead that of the IC band by 0.3 to 1.5 h. On inter‐night time‐scales, no lag was found between g′ and IC bands. On inter‐night time‐scales as well as intra‐night time‐scales on most of the nights, the amplitude of variability was found to increase towards shorter wavelengths. The flux variations in the different bands were not achromatic, with the blazar tending to become bluer when brighter on both inter‐night and intra‐night time‐scales, and this might be attributed to the larger amplitude variation at shorter wavelengths. A clear periodic variation of 3.3 h was found on 2008 April 1 and a hint for another possible periodic variability of 4 h was found on 2008 March 31. During our 30 days of observations over a 2 month period, the source has varied with an amplitude of variability as large as ∼80 per cent.

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“…Presently, a number of statistical tests, such as the C-test, the F-test, the χ 2 -test and one-way analysis of variance (ANOVA), have been proposed to assess quantitatively whether there are IDVs [6,9,[19][20][21][22][23]. Here, we apply the F-test and χ 2 -test to cross-check the intra-day light curves.…”

Section: Variabilitymentioning

confidence: 99%

Intra-Night Variability of OJ 287 with Long-Term Multiband Optical Monitoring

Zeng

Zhao²,

Jiang

et al. 2017

Galaxies

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Abstract:We present long-term optical multi-band photometric monitoring of the blazar OJ 287 from 6 March 2010 to 3 April 2016, with high temporal resolution in the VRI-bands. The flux variations and colour-magnitude variations on long and short timescales were investigated to understand the emission mechanisms. In our observation, the major outbursts occurred in January 2016, as predicted by the binary pair of black holes model for OJ 287, with F var of 1.3∼2.1%, and variability amplitude (Amp) of 5.8∼9.0%. The intra-night variability (IDV) durations were from 18.5 to 51.3 min, and the minimal variability timescale was about 4.7 min. The colour-magnitude variation showed a weak positive correlation on the long timescale with Pearson's r = 0.450, while a negative correlation was found on intra-night timescales. We briefly discuss the possible physical mechanisms that are most likely to be responsible for the observed flux and colour-magnitude correlation variability.

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The long-term multiband optical observations and colour index for the quasar 3C 273

Cited by 56 publications

References 54 publications

Optical intraday variability studies of 10 low energy peaked blazars

Optical intraday variability studies of 10 low energy peaked blazars

Simultaneous MITSuMEg′R_CI_Cmonitoring of S5 0716+714

Intra-Night Variability of OJ 287 with Long-Term Multiband Optical Monitoring

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The long-term multiband optical observations and colour index for the quasar 3C 273

Cited by 56 publications

References 54 publications

Optical intraday variability studies of 10 low energy peaked blazars

Optical intraday variability studies of 10 low energy peaked blazars

Simultaneous MITSuMEg′RCICmonitoring of S5 0716+714

Intra-Night Variability of OJ 287 with Long-Term Multiband Optical Monitoring

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Simultaneous MITSuMEg′R_CI_Cmonitoring of S5 0716+714