Photoelectric intraday observations of BL Lacertae, 3C 66 A, B2 1652 + 39, and 3C 371

McGimsey, B. Q.

doi:10.1086/155878

Cited by 29 publications

(19 citation statements)

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“…Barbieri et al 1982;Folsom et al 1976). Miller & McGimsey (1978) state that in the Harvard plate col lection measurements the variability amplitude for this blazar has been A5=2.0 magnitudes, which is typical for BL Lac objects. Sillanpaa et al (1991) saw a 1.4 magni tude flare during October 1985.…”

Section: History Of 3c 66amentioning

confidence: 81%

“…No clear evidence for intraday variability has been observed (e.g. Folsom et al 1976;Miller & McGimsey 1978;Takalo et al 1992a;Xie et al 1992). Carini & Miller (1991) have reported on variations as fast as 0.09T0.02 mag/hr, which they claim to suggest a characteristic time scale for the variations in 3C 66A of 12 hours.…”

Section: History Of 3c 66amentioning

confidence: 98%

“…Note the much higher brightness observed during this campaign. The average magnitudes have previously been 15.5 in B and 15.0 in V. The historical light curve is based on data taken from the following references: Barbieri et al (1982), Brindle et al (1986), Corso et al (1986Corso et al ( , 1988, Folsom et al (1976), Miller & McGimsey (1978), Holmes et al (1984), Maccagni et al (1987), Mead et al (1990), Moles et al (1985), Pica et al (1980), Sillanpaa et al (1991), Sitko et al (1985), Smith et al (1987), Takalo (1991), Takalo et al (1992bTakalo et al ( , 1994, Valtaoja et al (1991), Worral et al (1986), and Xie et al (1987Xie et al ( , 1988aXie et al ( ,b, 1990Xie et al ( -1992, Wills & Wills (1974).…”

Section: History Of 3c 66amentioning

confidence: 99%

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Monitoring of 3C 66A during an extended outburst. I. The light curves

Takalo¹,

Sillanpää²,

Pursimo³

et al. 1996

Astron. Astrophys. Suppl. Ser.

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Abstract. -We present results from a two year intensive monitoring of BL Lac object 3C 66A (PKS 0219+428).This object was observed in outburst during these two years. It reached the brightest ever observed magnitude on V=13.59 (1.2.1995) and on K=10.59 (15.2.1994). The optical and infrared light curves are characterised by randomly distributed fast flares, lasting a few days and well defined outbursts lasting a week or two. On top of these flares we can occasionally see small amplitude microvariability. No clear correlation can be found between the spectral behaviour and the occurrence of these flares. In the radio bands 3C 66A was quite faint and very stable compared to the optical variations. The light curves will be presented with preliminary analysis and discussions on the possible causes for the observed variations.

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Section: History Of 3c 66amentioning

confidence: 81%

Section: History Of 3c 66amentioning

confidence: 98%

Section: History Of 3c 66amentioning

confidence: 99%

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Monitoring of 3C 66A during an extended outburst. I. The light curves

Takalo¹,

Sillanpää²,

Pursimo³

et al. 1996

Astron. Astrophys. Suppl. Ser.

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“…The optical counterpart of the radio source 3C 66A was first identified by Wills & Wills (1974); derived a redshift z = 0.444 from a broad emission feature identified with a Mg II line. The classification as a BL Lac object is also supported by the high optical polarisation (16%, Mead et al 1990) and by the brightness variability with an amplitude of about 2 mag (Folsom et al 1976;Miller & McGimsey 1978).…”

Section: Introductionmentioning

confidence: 85%

X-ray and optical observations of BL Lac objects: 3C 66A (B0219+428) and ON 325 (B1215+303)

Perri

Massaro

Giommi

et al. 2003

A&A

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Abstract.We report the results of new observations of the two BL Lac objects 3C 66A and ON 325 performed with BeppoSAX and of nearly simultaneous photometric measurements in the bandpasses from I to B. 3C 66A was observed in January 1999 and in July 2001: its X-ray flux was F(2−10 keV) = 2.0−12 erg cm −2 s −1 in January 1999 and F(2−10 keV) = (2.6 ± 0.6) × 10 −12 erg cm −2 s −1 in July 2001. In both observations the X-ray spectrum can be fitted by a single power law with an energy index 1.2 ± 0.1, steeper than that measured in the optical, equal to 0.86 ± 0.05. The BeppoSAX observation of ON 325 was performed in December 1998 when its X-ray flux was F(2−10 keV) = 8 +3 −4 × 10 −13 erg cm −2 s −1 . The X-ray spectrum cannot be fitted by a single power law, but it is found to be well represented by a broken power law with a break energy at around 4 keV and energy indices equal to 1.48 ± 0.12 and −0.57 ± 0.63. Both sources are characterised by a synchrotron-dominated emission at energies lower than a few keV, with a sharp flattening toward higher energies due to the inverse Compton component. We obtained satisfactory modelling of the overall spectral energy distributions, from the optical to low energy X-rays, with logparabolic laws.

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“…3C 371 was one of the first quasars found to be variable on time scales of years/months/days. Optical variability studies have been conducted by Oke (1967), Sandage (1967), Usher & Manley (1968), Miller & McGimsey (1978), and Webb et al (1998). Carini et al (1998) presented dense optical monitoring observations of the source in the V band, over a period of five nights.…”

Section: Introductionmentioning

confidence: 99%

B and I-band optical micro-variability observations of the BL Lac objects S5 2007+777 and 3C 371

Xilouris¹,

Papadakis

Boumis³

et al. 2006

A&A

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We have observed S5 2007+777 and 3C 371 in the B and I bands for 13 and 8 nights, respectively, during various observing runs in 2001, 2002 and 2004. The observations resulted in almost evenly sampled light curves, 6−9 h long. We do not detect any flares within the observed light curves, but we do observe small amplitude, significant variations, in both bands, on time scales of hours and days. The average variability amplitude on time scales of minutes/hours is ∼2.5% and ∼1−1.5% in the case of S5 2007+777 and 3C 371, respectively. The average amplitudes increase to ∼ 5−12% and ∼ 4−6%, respectively, on time scales of days. We find that the B and I band variations are highly correlated, on both short and long time scales. During the 2004 observations, which resulted in the longest light curves, we observe two well defined flux-decay and rising trends in the light curves of both objects. When the flux decays, we observe significant delays, with the B band flux decaying faster than the flux in the I band. As a result, we also observe significant, flux related spectral variations as well. The flux-spectral relation is rather complicated, with loop-like structures forming during the flux evolution. The presence of spectral variations imply that the observed variability is not caused by geometric effects. On the other hand, our results are fully consistent with the hypothesis that the observed variations are caused by perturbations which affect different regions in the jet of the sources.

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Photoelectric intraday observations of BL Lacertae, 3C 66 A, B2 1652 + 39, and 3C 371

Cited by 29 publications

References 0 publications

Monitoring of 3C 66A during an extended outburst. I. The light curves

Monitoring of 3C 66A during an extended outburst. I. The light curves

X-ray and optical observations of BL Lac objects: 3C 66A (B0219+428) and ON 325 (B1215+303)

B and I-band optical micro-variability observations of the BL Lac objects S5 2007+777 and 3C 371

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