A Precessing Disk in OJ 287?

Katz, J. I.

doi:10.1086/303811

Cited by 175 publications

(205 citation statements)

References 13 publications

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“…In BL Lac, an accretion disk has indeed been proposed by Corbett et al (1996) and Corbett et al (2000) as the powering source of the observed, variable Hα emission line. The presence of an accretion disk in OJ 287 has been invoked to explain the observed flux and spectral variability (Sillanpää et al 1988;Kidger et al 1991;Katz 1997). However, the P ν of OJ 287 in past polarimetric monitorings in optical bands has not been systematically negative (see e.g.…”

Section: Discussionmentioning

confidence: 99%

Multiband optical polarimetry of BL Lacertae objects with the Nordic Optical Telescope

Tommasi

Palazzi

Pian

et al. 2001

A&A

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Abstract. Optical polarization of seven selected BL Lac objects in UBV RI bands was studied with the Nordic Optical Telescope from December 10-14, 1999. Two of them, 3C 66A and PKS 0735+178, were monitored for 4 nights for a total integration time of 4.75 and 5.5 hours, respectively. Other objects (1 Jy 0138−097, H 0414+009, PKS 0823−223, OJ287 and BL Lac) were observed sparsely during the run. Apart from PKS 0823−223 (more polarized than observed in the past), the sources show levels of flux and polarization consistent with results at previous epochs. 3C 66A and PKS 0735+178 were intensively observed during December 11 and 12 and exhibited variability of polarization, both on internight and intranight time scales. Wavelength dependence of polarization has been investigated, as well as circular polarization. The results are discussed within the standard model for BL Lacs.

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Section: Discussionmentioning

confidence: 99%

Multiband optical polarimetry of BL Lacertae objects with the Nordic Optical Telescope

Tommasi

Palazzi

Pian

et al. 2001

A&A

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“…SMBH), precession can occur as a result of the Bardeen-Petterson effect (Caproni et al 2006), magnetic torques (Lai 2003) or magnetohydrodynamic instabilities, prominently Kelvin-Helmholtz instabilities (e.g., Camenzind & Krockenberger 1992; Hardee & Norman 1988;Birkinshaw 1991;Zhao et al 1992;Hardee et al 1994;Hardee et al 1997;Meier & Nakamura 2006;Perucho et al 2006). If we assume that the AGN core hosts a binary system (presumably a binary black hole, BBH) then precession can occur as a result of the orbital motion of the binary system (e.g., Lobanov & Roland 2005;Roos et al 1993;Kaastra & Roos 1992), tidal forces, gravitational torques (e.g., Katz 1997;Romero et al 2000), as well as orbital motion of the system around the galactic gravity center (Roland et al 2008). …”

Section: Apparent Stationarity and Non-radial Motion Of Jet Componentsmentioning

confidence: 99%

“…Schramm et al (1993), find that the lighthouse effect is possibly responsible for the optical variability for the blazar 3C 345, although they consider that extrinsic effects (e.g., microlensing) could also contribute to the long-term variability observed. For OJ 287, Katz (1997) argues that a precessing disk consequently results in beaming effects for the jet and variability in the fluxdensity. For the same source, Villata et al (1998), proposed a beaming model for which both black holes of a BBH system produce a jet.…”

Section: Correlation Between Kinematics and Flux-density Variabilitymentioning

confidence: 99%

Non-radial motion in the TeV blazar S5 0716+714

Britzen¹,

Kam²,

Witzel³

et al. 2009

A&A

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Context. Flat-spectrum radio sources often show a core-jet structure on pc-scales. Individual jet components reveal predominantly outward directed motion. For the BL Lac object S5 0716+714 conflicting apparent velocities have been reported in the literature. This object is an intra-day variable source and suited to investigate a possible correlation between kinematic properties and flux-density variability on different timescales. Aims. We study the kinematics in the pc-scale jet of S5 0716+714 to determine the apparent speeds of the jet components based on a much improved data set. In addition, we search for correlations between the radio flux-density light curves and the morphological changes detected along the VLBI jet. Methods. We (re-)analyze 50 VLBI observations obtained with the VLBA at 5 different frequencies (5-43 GHz) between 1992.73 and 2006.32. The data have been parameterized using circular Gaussian components. We analyze the jet component motion in detail taking care not only to account for motion in the radial but also in the orthogonal direction. We study the evolution of the jet ridge line and investigate the spectral properties of the individual components. We search for correlations between radio band light curves and the kinematic properties of the jet components. Results. We present an alternative kinematic scenario for jet component motion in S5 0716+714. We present evidence for the apparent stationarity of jet components (with regard to their core separation) with time. Jet components, however, do seem to move significantly non-radially with regard to their position angle and in a direction perpendicular to the major axis of the jet. We discuss a possible correlation between the long-term radio flux-density variability and apparent jet component motions. Conclusions. In S5 0716+714 an alternative motion scenario is proposed. With regard to the core separation, rather stationary components can fit the VLBI observations well. A new model to explain the observed motion with regard to the position angle is required. Based on the correlation between the longterm radio flux-density variability and the position angle evolution of a jet component, we conclude that a geometric contribution to the origin of the long-term variability might not be negligible. Subluminal motion has been reported for most of the TeV blazars. Our analysis also confirms this finding for the case of S5 0716+714. This result increases the number of TeV blazars showing apparent subluminal motion to 7.

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“…First was the possibility that some stars might have started with two planets of Jupiter-like mass, whose encounters kicked one out completely and knocked the other inward to an eccentric, shortperiod orbit (Rasio & Ford 1996;Weidenschilling & Marzari 1996), though the highest eccentricities seen apparently require more than a single encounter between the planets (Katz 1997b). Second, alternative ways of achieving high eccentricity came from Lin & Ida (1997), who considered interaction with the residual disk, and from Holman et al (1997) and Mazeh et al (1997a), who blamed the companion star for the specific case of 16 Cyg B.…”

Section: The Primaries Of Extra-solar System Planetsmentioning

confidence: 99%

“…It has been modeled both as a binary black hole (Sundelius et al 1997;Valtonen & Lehto 1997) and as a precessing disk (Katz 1997a). As for other candidates, Hagen-Thorn et al (1997) suggest 15 yr for 3C 120, but on the basis of only 20 yr of data, while Lik et al (1997) rely on nearly 90 yr of brightness measurements in proposing a 23.1 yr period for Mrk 421.…”

Section: Some Galactic Extremamentioning

confidence: 99%

Astrophysics in 1997

Trimble¹,

McFadden²

1998

PUBL ASTRON SOC PAC

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ABSTRACT. Martian marvels, a gamma-ray burster with a redshift, Galileo converses with Ganymede, a record galactic redshift of 4.92, and much else. Fiscal 1997 was definitely an exciting year for astronomers. We have tried hard to hit all the obvious highlights, but also to report more gradual progress on traditional problems of understanding planets, stars, galaxies, and the universe. Though the year was saddened by the loss of many valued colleagues, we nevertheless indulge in occasional soupçons of frivolity.

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A Precessing Disk in OJ 287?

Cited by 175 publications

References 13 publications

Multiband optical polarimetry of BL Lacertae objects with the Nordic Optical Telescope

Multiband optical polarimetry of BL Lacertae objects with the Nordic Optical Telescope

Non-radial motion in the TeV blazar S5 0716+714

Astrophysics in 1997

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