Multiwavelength monitoring of the BL Lacertae object PKS 2155-304. 3: Ground-based observations in 1991 November

Courvoisier, T. J. L.; Blecha, A.; Bouchet, P.; Bratschi, P.; Carini, M. T.; Donahue, M.; Edelson, R.; Feigelson, E. D.; Filippenko, A. V.; Glass, Ian S.; Heidt, J.; Kollgaard, R. I.; Matheson, T.; Miller, H. R.; Noble, J. C.; Sekiguchi, K.; Smith, Paul S.; Urry, C. Megan; Wagner, S. J.

doi:10.1086/175058

Cited by 30 publications

(20 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For the uncertainties on the data points, see Table 2. (Brindle et al 1986 ;Mead et al 1990 ;Smith & Sitko 1991 ;Smith et al 1992 ;Allen et al 1993 ;Jannuzi et al 1993b ;Courvoisier et al 1995 ;Pesce et al 1997). be wavelength dependent because its spectrum should be signiÐcantly redder than that of the nucleus. In fact, given the measured magnitudes of the host galaxy (M H \ [26.8 ;Kotilainen, Falomo, & Scarpa 1998 and M I \ [24.2 ;Falomo et al 1991), using the color indices of a typical elliptical galaxy reported by Fukugita, Shimasaku, & Ichikawa (1995), Kotilainen et al (1998), andBertone et al (2000), we calculated the host galaxy Ñux in the F host UBV RI bands.…”

Section: Discussionmentioning

confidence: 99%

Multiband Optical Polarimetry of the BL Lacertae Object PKS 2155−304: Intranight and Long‐Term Variability

Tommasi

Díaz

Palazzi

et al. 2001

ASTROPHYS J SUPPL S

View full text Add to dashboard Cite

The polarized and total Ñux of the BL Lac object PKS 2155[304 were monitored intensively and simultaneously in the optical UBV RI bands with the Turin photopolarimeter at the CASLEO 2.15 m telescope during four campaigns in 1998 June, August, and November and 1999 August. The e †ective observation time amounted to D47 hr. PKS 2155[304 showed a linear polarization percentage (P) usually ranging between 3% and 7% and a polarization position angle (P.A.) mainly between 70¡ and 120¡. The highest temporal resolution of our observations, 15 minutes, is unprecedented for polarimetric monitoring of this source and has allowed us to detect amplitude variations of the linear polarization percentage from 6% to 7.5% in timescales of hours. In some nights the polarization percentage seems to increase toward shorter wavelengths ; however, the polarized spectrum does not vary signiÐcantly with time. The most remarkable variability event occurred on 1998 June 18, when the degree of linear polarization decreased by more than a factor 2 in 1 day in all bands, while the P.A. rotated by 90¡. This is consistent with the presence of two emission components, of di †erent polarization degree and position angle. Intranight variability of P and P.A. can be interpreted with small-amplitude physical or geometrical changes within the jet. Measurements of the circular polarization over time intervals of days set upper limits of 0.2%. Simultaneous photometry taken with the Turin Photopolarimeter and with a CCD camera at Astronomical Observatory did not show light variations correlated with those of the Co rdoba linearly polarized Ñux.

show abstract

Section: Discussionmentioning

confidence: 99%

Multiband Optical Polarimetry of the BL Lacertae Object PKS 2155−304: Intranight and Long‐Term Variability

Tommasi

Díaz

Palazzi

et al. 2001

ASTROPHYS J SUPPL S

View full text Add to dashboard Cite

show abstract

“…(1) Griffiths et al (1979); (2) Griffiths et al (1979), (3) Miller & McAlister (1983), (4) Brindle et al (1986), (5) Hamuy & Maza (1987), (6) Pica et al (1988), (7) Treves et al (1989), (8) Mead et al (1990), (9) Smith & Sitko (1991), (10) Carini & Miller (1992), (11) Smith et al (1992), (12) Jannuzi et al (1993) and (13) Urry et al (1993) as collected in Zhang & Xie (1996); (14) Campbell (2004), (15) Courvoisier et al (1995) and (16) Pesce et al (1997) as collected in Osterman et al (2007); (17) Tommasi et al (2001). Table 1 shows statistics of the data on PKS 2155-304.…”

Section: Summary Of Observationsmentioning

confidence: 99%

Long-term optical variability of PKS 2155-304

Kastendieck

Ashley

Horns

2011

A&A

View full text Add to dashboard Cite

Aims. The optical variability of the blazar PKS 2155-304 is investigated to characterise the red noise behaviour at largely different time scales from 20 days to O(>10 yrs). Methods. The long-term optical light curve of PKS 2155-304 is assembled from archival data as well as from so-far unpublished observations mostly carried out with the ROTSE-III and the ASAS robotic telescopes. A forward folding technique is used to determine the best-fit parameters for a model of a power law with a break in the power spectral density function (PSD). The best-fit parameters are estimated using a maximum-likelihood method with simulated light curves in conjunction with the Lomb-Scargle periodogram and the first-order structure function (SF). In addition, a new approach based upon the so-called multiple fragments variance function (MFVF) is introduced and compared to the other methods. Simulated light curves have been used to confirm the reliability of these methods as well as to estimate the uncertainties of the best-fit parameters. Results. The light curve is consistent with the assumed broken power-law PSD. All three methods agree within the estimated uncertainties with the MFVF providing the most accurate results. The red-noise behaviour of the PSD in frequency f follows a power law with f −β , β = 1.8 +0.1 −0.2 and a break towards f 0 at frequencies lower than f min = (2.7 +2.2 −1.6 yrs) −1 .

show abstract

“…In the last two decades, variability of blazars in radio to optical bands on diverse time scales has been reported in a large number of papers (e.g. Miller et al 1989;Courvoisier et al 1995;Heidt & Wagner 1996;Takalo et al 1996;Sillanpää et al 1996aSillanpää et al , 1996bBai et al 1998Bai et al , 1999Fan et al 1998Fan et al , 2002Fan et al , 2007Xie et al 2002a;Gupta et al 2004;Ciprini et al 2003, 2007 andreferences therein).…”

Section: Introductionmentioning

confidence: 99%

Optical Intra-Day Variability in Blazars

Gupta

Jiang

Bai

et al. 2008

The Astronomical Journal

Self Cite

120

152

View full text Add to dashboard Cite

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.

show abstract

Multiwavelength monitoring of the BL Lacertae object PKS 2155-304. 3: Ground-based observations in 1991 November

Cited by 30 publications

References 0 publications

Multiband Optical Polarimetry of the BL Lacertae Object PKS 2155−304: Intranight and Long‐Term Variability

Multiband Optical Polarimetry of the BL Lacertae Object PKS 2155−304: Intranight and Long‐Term Variability

Long-term optical variability of PKS 2155-304

Optical Intra-Day Variability in Blazars

Contact Info

Product

Resources

About