Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
Synchronous optical and radio polarization variability in the blazar OJ287. / D'Arcangelo, Francesca D.; Marscher, Alan P.; Jorstad, Svetlana G.; Smith, Paul S.; Larionov, Valeri M.; Hagen-Thorn, Vladimir A.; Williams, G. Grant; Gear, Walter K.; Clemens, Dan P.; Sarcia, Domenic; Grabau, Alex; Tollestrup, Eric V.; Buie, Marc W.; Taylor, Brian; Dunham, Edward.
в: Astrophysical Journal, Том 697, № 2, 2009, стр. 985-995.Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
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TY - JOUR
T1 - Synchronous optical and radio polarization variability in the blazar OJ287
AU - D'Arcangelo, Francesca D.
AU - Marscher, Alan P.
AU - Jorstad, Svetlana G.
AU - Smith, Paul S.
AU - Larionov, Valeri M.
AU - Hagen-Thorn, Vladimir A.
AU - Williams, G. Grant
AU - Gear, Walter K.
AU - Clemens, Dan P.
AU - Sarcia, Domenic
AU - Grabau, Alex
AU - Tollestrup, Eric V.
AU - Buie, Marc W.
AU - Taylor, Brian
AU - Dunham, Edward
PY - 2009
Y1 - 2009
N2 - We explore the variability and cross-frequency correlation of the flux density and polarization of the blazar OJ287, using imaging at 43 GHz with the Very Long Baseline Array, as well as optical and near-infrared (near-IR) polarimetry. The polarization and flux density in both the optical waveband and the 43 GHz compact core increased by a small amount in late 2005, and increased significantly along with the near-IR polarization and flux density over the course of 10 days in early 2006. Furthermore, the values of the electric vector position angle (EVPA) at the three wavebands are similar. At 43 GHz, the EVPA of the blazar core is perpendicular to the flow of the jet, while the EVPAs of emerging superluminal knots are aligned parallel to the jet axis. The core polarization is that expected if shear aligns the magnetic field at the boundary between flows of disparate velocities within the jet. Using variations in flux density, percentage polarization, and EVPA, we model the inner jet as a spine-sheath system. The model jet contains a turbulent spine of half-width 12 and maximum Lorentz factor of 16.5, a turbulent sheath with Lorentz factor of 5, and a boundary region of sheared field between the spine and sheath. Transverse shocks propagating along the fast, turbulent spine can explain the superluminal knots. The observed flux density and polarization variations are then compatible with changes in the direction of the inner jet caused by a temporary change in the position of the core if the spine contains wiggles owing to an instability. In addition, we can explain a stable offset of optical and near-IR percentage polarization by a steepening of spectral index with frequency, as supported by the data.
AB - We explore the variability and cross-frequency correlation of the flux density and polarization of the blazar OJ287, using imaging at 43 GHz with the Very Long Baseline Array, as well as optical and near-infrared (near-IR) polarimetry. The polarization and flux density in both the optical waveband and the 43 GHz compact core increased by a small amount in late 2005, and increased significantly along with the near-IR polarization and flux density over the course of 10 days in early 2006. Furthermore, the values of the electric vector position angle (EVPA) at the three wavebands are similar. At 43 GHz, the EVPA of the blazar core is perpendicular to the flow of the jet, while the EVPAs of emerging superluminal knots are aligned parallel to the jet axis. The core polarization is that expected if shear aligns the magnetic field at the boundary between flows of disparate velocities within the jet. Using variations in flux density, percentage polarization, and EVPA, we model the inner jet as a spine-sheath system. The model jet contains a turbulent spine of half-width 12 and maximum Lorentz factor of 16.5, a turbulent sheath with Lorentz factor of 5, and a boundary region of sheared field between the spine and sheath. Transverse shocks propagating along the fast, turbulent spine can explain the superluminal knots. The observed flux density and polarization variations are then compatible with changes in the direction of the inner jet caused by a temporary change in the position of the core if the spine contains wiggles owing to an instability. In addition, we can explain a stable offset of optical and near-IR percentage polarization by a steepening of spectral index with frequency, as supported by the data.
KW - Polarization
KW - Quasars: general
KW - Quasars: individual (OJ287)
UR - http://www.scopus.com/inward/record.url?scp=66649132568&partnerID=8YFLogxK
U2 - 10.1088/0004-637X/697/2/985
DO - 10.1088/0004-637X/697/2/985
M3 - Article
AN - SCOPUS:66649132568
VL - 697
SP - 985
EP - 995
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 2
ER -
ID: 88377710