$BVR_{\rm c}I_{\rm c}$ monitoring of ON 231 during the great outburst in 1994-1997

Tosti, G.; Fiorucci, M.; Luciani, M.; Rizzi, N.; Villata, M.; Raiteri, C. M.; Francesco, G. de; Lanteri, L.; Chiaberge, M.; Peila, A.; Cavallone, M.; Sobrito, G.; Maesano, M.; Massaro, E.; Montagni, F.; Nesci, R.; Ghisellini, G.; Takalo, L. O.; Sillanpää, A.; Katajainen, S.; Heinämäki, P.; Nilsson, K.; Pursimo, T.

doi:10.1051/aas:1998215

Cited by 23 publications

(10 citation statements)

References 24 publications

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“…In the present observations, we observed the source at R ∼ 15.0 mag. Therefore, it appears likely that we have observed the source in the low state which is comparable to the faintest state observed by Tosti et al (1998).…”

supporting

confidence: 61%

“…ON 231 at redshift z = 0.102 is classified as a BL Lac object (Browne 1971). The historical B passband light curve of the source was plotted by Tosti et al (1998). There have not been many attempts to study the variability behavior of the source.…”

mentioning

confidence: 99%

“…We also performed the IDV detection test and found that the value of C is 1.06, which also confirms that the source did not show IDV on one night of our observations. Tosti et al (1998) carried out multi-band optical monitoring of the source for three years (1994)(1995)(1996)(1997) in its great outburst state. The 1994-1997 light curve of the source shows the brightest (∼13.5 mag) and faintest (∼15.0 mag) states in the R passband.…”

mentioning

confidence: 99%

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Optical Intra-Day Variability in Blazars

Gupta

Jiang

Bai

et al. 2008

The Astronomical Journal

120

152

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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 (IDV) and short-term variability in these blazars. We carried out optical photometric monitoring of nine of these blazars in 13 observing nights during our observing run of 2006 October 27-2007 March 20 using the 1.02 m optical telescope equipped with CCD detector and BVRI Johnson broadband filters at Yunnan Astronomical Observatory, Kunming, China. From our observations, our data favor the hypothesis that three blazars, AO 0235+164, S5 0716+714, and 3C 279, were in the outburst state; one blazar, 3C 454.3, was in the post-outburst state; three blazars, S2 0109+224, PKS 0735+178, and OJ 287, were in the pre/post-outburst state; one blazar, ON 231, was in the low state; and the state of one blazar, 1ES 2344+514, was not known because there are not many optical data available for the blazar to compare with our observations. We observed densely sampled 1534 image frames of these nine blazars. Out of three nights of observations of AO 0235+164, IDV was detected in two nights. Out of five nights of observations of S5 0716+714, IDV was detected in two nights. In one night of observations of PKS 0735+178, IDV was detected. Out of six nights of observations of 3C 454.3, IDV was detected in three nights. No IDV was detected in S2 0109+224, OJ 287, ON 231, 3C 279, and 1ES 2344+514 in their one, four, one, two, and one nights of observations, respectively. AO 0235+164, S5 0716+714, OJ 287, 3C 279, and 3C 454.3 were observed in more than one night and short-term variations in all these blazars were also noticed. From our observations and the available data, we found that the predicted optical outbursts with time intervals of ∼8 years in AO 0235+164 and ∼3 years in S5 0716+714 have possibly occurred.

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supporting

confidence: 61%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Optical Intra-Day Variability in Blazars

Gupta

Jiang

Bai

et al. 2008

The Astronomical Journal

120

152

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“…The historical B passband LC of the source (during 1935-1997) was plotted by Tosti et al (1998). It has shown optical flux variations on diverse timescales ranging from a few hours to several years (Xie et al 1992;Smith & Nair 1995).…”

Section: Power Spectral Densitymentioning

confidence: 99%

DETECTION OF INTRA-DAY VARIABILITY TIMESCALES OF FOUR HIGH-ENERGY PEAKED BLAZARS WITHXMM-NEWTON

Gaur¹,

Gupta²,

Lachowicz³

et al. 2010

ApJ

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We selected a sample of 24 XMM-Newton light curves (LCs) of four high energy peaked blazars, PKS 0548−322, ON 231, 1ES 1426+428 and PKS 2155−304. These data comprise continuous light curves of 7.67h to 18.97h in length. We searched for possible quasi-periodic oscillations (QPO) and intra-day variability (IDV) timescales in the LCs of these blazars. We found a likely QPO in one LC of PKS 2155−304 which was reported elsewhere (Lachowicz et al. 2009). In the remaining 23 LCs we found hints of possible weak QPOs in one LC of each of ON 231 and PKS 2155−304, but neither is statistically significant. We found IDV timescales that ranged from 15.7 ks to 46.8 ks in 8 LCs. In 13 LCs any variability timescales were longer than the length of the data. Assuming the possible weak QPO periods in the blazars PKS 2155−304 and ON 231 are real and are associated with the innermost portions of their accretion disk, we can estimate that their central black hole masses exceed 1.2 × 10 7 M ⊙ . Emission models for radio-loud active galactic nuclei (AGN) that could explain our results are briefly discussed.

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“…or on data on flaring periods of single sources (like GC 0109+224, S5 0716+71, Mrk 421, W Com, BL Lac) can be found for example in [18,19,15,5,4,3].…”

Section: The Blazar Monitoring Programmentioning

confidence: 99%

The Perugia variability monitoring of blazars

Ciprini¹

2009

Proceedings of Workshop on Blazar Variability Across the Electromagnetic Spectrum — PoS(BLAZARS2008)

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In fifteen years of optical monitoring performed with the 0.4m automatic imaging telescope (AIT) of the Perugia University Observatory, more than 35000 VRI (and a few B) photometric data points were collected, contributing to get an important database of the multi-band optical history of 37 blazars brighter than V-mag 17. This blazar variability monitoring started in 1991, with a fully robotic implementation operational from 1994. Despite of the limited budget, manpower and telescope size, such long-term program allowed to obtain light curves of blazars with a rather unprecedented continuity and sampling for about a dozen of our targets (considering data usually obtained by a single telescope). This effort was very useful to trigger observations and campaigns at other frequencies, to study the optical variability modes and the temporal behavior on intermediate and long timescales. Some highlights and examples of results are briefly reported.

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$BVR_{\rm c}I_{\rm c}$ monitoring of ON 231 during the great outburst in 1994-1997

Cited by 23 publications

References 24 publications

Optical Intra-Day Variability in Blazars

Optical Intra-Day Variability in Blazars

DETECTION OF INTRA-DAY VARIABILITY TIMESCALES OF FOUR HIGH-ENERGY PEAKED BLAZARS WITHXMM-NEWTON

The Perugia variability monitoring of blazars

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