The infrared and optical variability of OJ 287

Jiang, Fan; Adam, Gilles; Xie, Gaogang; Cao, Shixiu; Lin, R. G.; Qin, Yi-Ping; Copin, Y.; Bai, J. M.; Zhang, X.; Li, K. H.

doi:10.1051/aas:1998314

Cited by 25 publications

(15 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The scatter in the B − V index increased when the object became fainter than 14. m 5. A close correlation between the B − V color index and the V magnitude was found by Fan et al (1998) based on a dozen points obtained in winter 1994-95, at the falling branch of brightness after the maximum in 1994.…”

Section: Color Variationssupporting

confidence: 60%

Photopolarimetric monitoring of OJ 287 in 1994–1997

Efimov¹,

Shakhovskoy²,

Takalo³

et al. 2002

A&A

View full text Add to dashboard Cite

Abstract. We present and discuss the UBV RI photopolarimetric data of blazar OJ 287 obtained at the Crimean Astrophysical Observatory from January 1994 until April 1997 as a part of the international OJ-94 campaign. The variations of brightness and linear polarization detected in all used optical bands are similar. No clear correlation was found between the brightness variations and polarization parameters. The most prominent characteristic in the object variability is the apparent continuous rotation of the observed polarization position angle in 1994-1996. The rate of this rotation over two observational seasons in 1994-1995 and 1995-1996 is about 4.• 92/day in a clockwise direction. This rate corresponds to the full 360• rotation of the polarization plane in about 73 days. We consider the rotation of the plane of polarization as direct evidence for helical magnetic field structure in the jet of OJ 287.

show abstract

Section: Color Variationssupporting

confidence: 60%

Photopolarimetric monitoring of OJ 287 in 1994–1997

Efimov¹,

Shakhovskoy²,

Takalo³

et al. 2002

A&A

View full text Add to dashboard Cite

show abstract

“…No significant negative correlation was found for any BL Lac which reflects the common trend for this class that they become bluer when they brighten (Ghisellini et al 1997;Fan et al 1998;Massaro et al 1998;Fan & Lin 1999;Ghosh et al 2000;Raiteri et al 2001;Villata et al 2002;Gu et al 2006;Rani et al 2010a). It has been found that the amplitude of the variations is systematically larger at higher frequencies, which suggests that the spectrum becomes steeper when the source brightness decreases, and flatter when it increases (Ghisellini et al 1997;Massaro et al 1998).…”

Section: Relation Between Colour Index and Flux Variationmentioning

confidence: 87%

“…BL Lac has been studied in detail during various intensive multiwavelength campaigns (Madejski et al 1999;Villata et al 2002;Böttcher et al 2003;Ravasio et al 2003 and references therein). Fan et al (1998) presented historical optical data (in UBVRI) over ∼100 yr covering the period 1896-1996 and found large variations in all the bands.…”

Section: Bl Lacmentioning

confidence: 99%

Optical flux and spectral variability of blazars

Gaur

Gupta

Strigachev

et al. 2012

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We report the results of optical monitoring for a sample of 11 blazars including 10 BL Lacertae objects (BL Lacs) and one flat spectrum radio quasar (FSRQ). We have measured the multiband optical flux and colour variations in these blazars on intraday and short-term time-scales of months and have limited data for two more blazars. These photometric observations were made during 2009-2011, using six optical telescopes, four in Bulgaria, one in Greece and one in India. On short-term time-scales we found significant flux variations in nine of the sources and colour variations in three of them. Intraday variability was detected on six nights for two sources out of the 18 nights and four sources for which we collected such data. These new optical observations of these blazars plus data from our previous published papers (for three more blazars) were used to analyse their spectral flux distributions in the optical frequency range. Our full sample for this purpose includes six high-synchrotron-frequency-peaked BL Lacs (HSPs), three intermediate-synchrotron-frequency-peaked BL Lacs (ISPs) and six lowsynchrotron-frequency-peaked BL Lacs (LSPs; including both BL Lacs and FSRQs). We also investigated the spectral slope variability and found that the average spectral slopes of LSPs show a good accordance with the synchrotron self-Compton loss dominated model. Our analysis supports previous studies that found that the spectra of the HSPs and FSRQs have significant additional emission components. The spectra of all these HSPs and LSPs get flatter when they become brighter, while for FSRQs the opposite appears to hold. This supports the hypothesis that there is a significant thermal contribution to the optical spectrum for FSRQs.

show abstract

“…2, 9 and 12) observed during the latest outbursts show clearly that during the first optical flare the radio bands showed minimum flux (see Valtaoja et al 2000). Figure 2 shows the observed optical light curves, displaying clearly the outbursts in November 1994 and end of December 1995 (Arimoto et al 1997;Fan et al 1998b;Kidger et al 1995;Sillanpää et al 1996a,b). The separation between these two outbursts is 1.1 years (Sillanpää et al 1996b;, which is very similar to the one observed in 1972/73 and 1983/84 (Sillanpää et al 1988).…”

Section: Resultsmentioning

confidence: 89%

“…The project archive contains also the data published by Arimoto et al (1997), Fan et al (1998b), Jia et al (1998) and Stevens et al (1994). These data will be also used in the following sections of this article.…”

Section: Fig 3 Example Of the Observed Flaring Activity In Differenmentioning

confidence: 99%