Multiwaveband Polarimetric Observations of 15 Active Galactic Nuclei at High Frequencies: Correlated Polarization Behavior
By S. Jorstad, A. Marscher, J. Stevens, Paul S. Smith, J. Forster, W. Gear, T. Cawthorne, M. Lister, A. Stirling, J. Gómez and 2 more. 2007
145 citations recorded by the source corpus.
We report on multifrequency linear polarization monitoring of 15 active galactic nuclei containing highly relativistic jets with apparent speeds from ∼4c to >40c. The measurements were obtained at optical, 1 mm, and 3 mm wavelengths, and at 7 mm with the Very Long Baseline Array. The data show a wide range in degree of linear polarization among the sources, from <1% to >30%, and interday polarization variability in individual sources. The polarization properties suggest separation of the sample into three groups with low, intermediate, and high variability of polarization in the core at 7 mm (LVP, IVP, and HVP, respectively). The groups are partially associated with the common classification of active galactic nuclei as radio galaxies and quasars with low optical polarization (LVP), BL Lacertae objects (IVP), and highly optically polarized quasars (HVP). Our study investigates correlations between total flux, fractional polarization, and polarization position angle at the different wavelengths. We interpret the polarization properties of the sources in the sample through models in which weak shocks compress turbulent plasma in the jet. The differences in the orientation of sources with respect to the observer, jet kinematics, and abundance of thermal matter external to the jet near the core can account for the diversity in the polarization properties. The results provide strong evidence that the optical polarized emission originates in shocks, most likely situated between the 3 and 7 mm VLBI cores. They also support the idea that the 1 mm core lies at the edge of the transition zone between electromagnetically dominated and turbulent hydrodynamic sections of the jet.
Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics
View Paper: https://www.semanticscholar.org/paper/bc83f18c22be8900329690156faf547ed3ecb3d4
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In Astronomy and Astrophysics
- A. Marscher
- M. Tornikoski
- A. Lähteenmäki
- S. Jorstad
- J. Gómez
- H. Wiesemeyer
- Paul S. Smith
- A. Markowitz
In Nuclear and High Energy Physics
Citations in the corpus
- FLARING BEHAVIOR OF THE QUASAR 3C 454.3 ACROSS THE ELECTROMAGNETIC SPECTRUM (2010, background): “However, analysis of polarization properties in quasars (Jorstad et al. 2007; D’Arcangelo et al. 2007) shows that the polarized optical emission, although partially co-spatial with the mm-wave core, occupies a volume that is thousands of times less than does the polarized emission at 43 GHz.”
- LOCATION OF γ-RAY FLARE EMISSION IN THE JET OF THE BL LACERTAE OBJECT OJ287 MORE THAN 14 pc FROM THE CENTRAL ENGINE (2010, background): “The actual distance between the central engine in OJ287 and C1 must be even greater if C0 lies downstream of the acceleration and collimation zone of the jet (ACZ; Jorstad et al. 2007; Marscher et al. 2008, 2010).”
- TURBULENT, EXTREME MULTI-ZONE MODEL FOR SIMULATING FLUX AND POLARIZATION VARIABILITY IN BLAZARS (2013, background): “The jet opening angle φ is assumed to be so small (see Jorstad et al. 2007; Pushkarev et al. 2012) that expansion cooling is not important within the section of the jet under consideration.”