Abstrakti
We describe the parsec-scale kinematics of 200 active galactic nucleus
(AGN) jets based on 15 GHz Very Long Baseline Array (VLBA) data obtained
between 1994 August 31 and 2011 May 1. We present new VLBA 15 GHz images
of these and 59 additional AGNs from the MOJAVE and 2 cm Survey
programs. Nearly all of the 60 most heavily observed jets show
significant changes in their innermost position angle over a 12-16 yr
interval, ranging from 10° to 150° on the sky, corresponding to
intrinsic variations of ~0.°5 to ~2°. The BL Lac jets show
smaller variations than quasars. Roughly half of the heavily observed
jets show systematic position angle trends with time, and 20 show
indications of oscillatory behavior. The time spans of the data sets are
too short compared to the fitted periods (5-12 yr), however, to reliably
establish periodicity. The rapid changes and large jumps in position
angle seen in many cases suggest that the superluminal AGN jet features
occupy only a portion of the entire jet cross section and may be
energized portions of thin instability structures within the jet. We
have derived vector proper motions for 887 moving features in 200 jets
having at least five VLBA epochs. For 557 well-sampled features, there
are sufficient data to additionally study possible accelerations. We
find that the moving features are generally non-ballistic, with 70% of
the well-sampled features showing either significant accelerations or
non-radial motions. Inward motions are rare (2% of all features), are
slow (
Alkuperäiskieli | Englanti |
---|---|
Artikkeli | 120 |
Sivumäärä | 22 |
Julkaisu | Astronomical Journal |
Vuosikerta | 146 |
Numero | 5 |
DOI - pysyväislinkit | |
Tila | Julkaistu - 2013 |
OKM-julkaisutyyppi | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä |