Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Kinematic study of the parsec-scale jet of the quasar PKS 1741--03   We present 23 interferometric images of parsec-scale jet of the quasar PKS
1741--03 at 15, 24 and 43 GHz spanning about 13 yr. We model the images as a
superposition of discrete two--dimensional elliptical Gaussian components, with
parameters determined by the cross--entropy technique. All the images present a
spatially unresolved component (core) and usually two or three components
receding from it. The same components were found in simultaneous 24 and 43 GHz
maps, showing the robustness of our model-fitting. The core-shift opacity
effect between these frequencies is weak. We have identified seven components
moving along straight lines at constant apparent superluminal speeds
($3.5\le\beta_\mathrm{obs}\le 6.1$), with different sky position angles
($-186\deg\le \eta\le -125\deg$). The core flux density tracks quite well the
fluctuations seen in the historical single-dish light curve at 14.5 GHz, with
no measurable delay. The total flux density from the moving jet components is
delayed $\sim$2 yr in relation to the core light curve, roughly the same as the
lag between the ejection epoch and the maximum flux density in the light curves
of the jet components. We propose that there are three non-exclusive mechanisms
for producing these delays. From the kinematics of the most robust jet
components and the core brightness temperature, we determined the bulk Lorentz
factor ($4.8\le\gamma\le 24.5$) and the jet viewing angle ($0.\deg 35 \le
\theta \le 4.\deg 2$); these values agree with previous estimates from the
spectral energy distribution of PKS 1741--03 and its radio variability.

30
The categories of this paper are: q-alg
32
The categories of this paper are: atom-ph
4
The categories of this paper are: cond-mat
37
The categories of this paper are: supr-con
7
The categories of this paper are: hep-th
29
The categories of this paper are: funct-an
11
The categories of this paper are: hep-lat
27
The categories of this paper are: comp-gas
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
0
The categories of this paper are: hep-ph
17
The categories of this paper are: q-fin
24
The categories of this paper are: dg-ga
26
The categories of this paper are: bayes-an
22
The categories of this paper are: chao-dyn