Open AccessPolarization and kinematics in Cygnus A
Author(s) -
Van Bemmel Ilse M.,
Vernet Joël,
Fosbury Robert A. E.,
Lamers Henny J. G. L. M.
Publication year - 2003
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2003.07141.x
Subject(s) - physics , torus , astrophysics , quasar , ionization , polarization (electrochemistry) , emission spectrum , scattering , astronomy , radiation pressure , spectral line , optics , galaxy , geometry , chemistry , ion , mathematics , quantum mechanics
From optical spectropolarimetry of Cygnus A, we conclude that the scattering medium in the ionization cones in Cygnus A is moving outward at a speed of 170 ± 34 km s −1 , and that the required momentum can be supplied by the radiation pressure of an average quasar. Such a process could produce a structure resembling the observed ionization cones, which are thought to result from shadowing by a circumnuclear dust torus. We detect a polarized red wing in the [O iii ] emission lines arising from the central kiloparsec of Cygnus A. This wing is consistent with line emission created close to the boundary of the broad‐line region.