Quasar CT 102
Movie (0.9
MB, AVI) of the evolution of the parsec-scale jet of the quasar CTA 102. 1 mas
= 8.0 parsecs for a Hubble constant of 65 km/s/Mpc. The red contours show total
intensity (starting at 64% of the peak and decreasing by factors of 2), while
the colored image corresponds to linearly polarized intensity. The white sticks
show the direction of the electric vector; the magnetic field is perpendicular
to the electric vector except perhaps in the most compact components, which
might be opaque. The lavender vector on the right shows the 230 GHz polarization
of the entire object as measured by the James Clerk Maxwell Telescope. The inset
shows the brightness (flux density) as measured by the JCMT, with the red arrow
showing the current date of the animation and green arrows showing epochs of
actual observations. The movie is made by linear interpolation of the data.
There is an unresolved stationary feature on the upper right (northwestern)
end, customarily called the "core." There is a second, larger, perhaps stationary
component about 2 mas southeast of the core. During the movie, a bright spot
(elegantly termed a "blob" by experts) emerges from the core and subsequently
travels down the jet at an apparent speed of 16c. This followed a major outburst
in radio brightness that occurred in 1997. The core continues to be polarized
after ejection of the blob until the last epoch, when it suddenly becomes unpolarized.
The moving blob and the core have magnetic field directions that are nearly
perpendicular to the jet direction, as expected for plane-wave shocks. This
movie was made by Svetlana Marchenko-Jorstad from data analyzed by her and Alan
Marscher, in collaboration with T. Cawthorne, A. Stirling, M. Lister, W. Gear,
J. Stevens, D. Gabuzda, E.I. Robson, J.R. Forster, and P. Smith.