The optical polarization of the blazar PKS 2155$-$304 during an optical flare in 2010

Abstract

An analysis is presented of the optical polarimetric and multicolour photometric ($BVRJ$) behaviour of the blazar PKS 2155$-$304 during an outburst in 2010. This flare develops over roughly 117 days, with a flux doubling time $\tau \sim 11$ days that increases from blue to red wavelengths. The polarization angle is initially aligned with the jet axis but rotates by roughly $90^{\circ }$ as the flare grows. Two distinct states are evident at low and high fluxes. Below 18 mJy, the polarization angle takes on a wide range of values, without any clear relation to the flux. In contrast, there is a positive correlation between the polarization angle and flux above 18 mJy. The polarization degree does not display a clear correlation with the flux. We find that the photopolarimetric behaviour for the high flux state can be attributed to a variable component with a steady power-law spectral energy distribution and high optical polarization degree (13.3%). These properties are interpreted within the shock-in-jet model, which shows that the observed variability can be explained by a shock that is seen nearly edge-on. Some parameters derived for the relativistic jet within the shock-in-jet model are: $B=0.06$ G for the magnetic field, $\delta =22.3$ for the Doppler factor and $\Phi =2.6^{\circ }$ for the viewing angle.

arXiv comment8 pages, 9 figures

References in corpus (25)

• Unified Schemes for Radio-Loud Active Galactic Nuclei
• The Spectral Energy Distribution of Fermi bright blazars
• An Exceptional VHE Gamma-Ray Flare of PKS 2155-304
• Turbulent, Extreme Multi-Zone Model for Simulating Flux and Polarization Variability in Blazars
• SMARTS optical and infrared monitoring of 12 gamma-ray bright blazars
• Polarization and structure of relativistic parsec-scale AGN jets
• Implications of very rapid TeV variability in blazars
• Simultaneous observations of PKS 2155-304 with H.E.S.S., Fermi, RXTE and ATOM: spectral energy distributions and variability in a low state
• The Jets of TeV Blazars at Higher Resolution: 43 GHz and Polarimetric VLBA Observations from 2005-2009
• Variability in Blazars: Clues from PKS 2155-304
• Coordinated Fermi/Optical Monitoring of Blazars and the Great 2009 September Gamma-ray Flare of 3C 454.3
• The Outburst of the Blazar AO 0235+164 in 2006 December: Shock-in-Jet Interpretation
• Intrinsic Differences in the Inner Jets of High- and Low-Optically Polarized Radio Quasars
• The Parsec-Scale Jets of the TeV Blazars H 1426+428, 1ES 1959+650, and PKS 2155-304: 2001-2004
• X-ray/UV/Optical follow-up of the blazar PKS 2155-304 after the giant TeV flares of July 2006
• Synchronous Optical and Radio Polarization Variability in the Blazar OJ287
• Oblique Shocks As The Origin Of Radio To Gamma-ray Variability In AGN
• Long-term optical variability of PKS 2155-304
• Time-dependent simulations of emission from FSRQ PKS1510-089: multiwavelength variability of external Compton and SSC models
• Long-term optical polarization variability of the tev blazar 1es~1959+650
• Anti-correlated Optical Flux and Polarization Variability in BL Lac
• Discovery of a Highly Polarized Optical Microflare in the Blazar S5 0716+714 During 2014 WEBT Campaign
• Particle Acceleration and Magnetic Field Structure in PKS 2155-304: Optical Polarimetric Observations
• A two-component model for the high-energy variability of blazars. Application to PKS 2155-304
• The magnetic field and geometry of the oblique shock in the jet of 3C 346

Cited by in corpus (3)

• X-ray Intraday Variability of the TeV Blazar PKS 2155-304 with Suzaku During 2005-2014
• Study of correlation between optical flux and polarization variations in BL Lac objects
• Correlations between $\gamma$-ray luminosity and magnetization of the jet as well as relativistic electron injection power:cases for Mrk 421, 3C 454.3 and 3C 279