摘要：We investigated the jet width profile with distance along the jet in the nearby radio galaxy NGC 1052 at radial distances between ~300 and 4 × 107 Schwarzschild radii (RS) from the central engine on both their approaching and receding jet sides.The width of jets was measured in images obtained with the Very Long Baseline Interferometry (VLBI) Space Observatory Programme, the Very Long Baseline Array, and the Very Large Array.The jet width profiles of receding jets are apparently consistent with those of approaching jets throughout the measuring distance ranges, indicating symmetry at least up to the sphere of gravitational influence of the central black hole.The power-law index a of the jet width profile (wjet ∝ ra, where wjet is the jet width, r is the distance from the central engine in the unit of RS) apparently shows a transition from a ~ 0 to a ~ 1, i.e., the cylindrical-to-conical jet structures, at a distance of ~1 × 104RS.The cylindrical jet shape at small distances is reminiscent of the innermost jets in 3C 84.Both the central engines of NGC 1052 and 3C 84 are surrounded by dense material, part of which is ionized and causes heavy free–free absorption.
关键词：Active galactic nuclei;Radio jets;Jets;Relativistic jets;Discrete radio sources;Fanaroff-Riley radio galaxies;Radio galaxies;Radio continuum emission
