Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The role of Kelvin-Helmholtz instability in the internal structure of
  relativistic outflows. The case of the jet in 3C 273   Relativistic outflows represent one of the best-suited tools to probe the
physics of AGN. Numerical modelling of internal structure of the relativistic
outflows on parsec scales provides important clues about the conditions and
dynamics of the material in the immediate vicinity of the central black holes
in AGN. We investigate possible causes of the structural patterns and
regularities observed in the parsec-scale jet of the well-known quasar 3C 273.
We present here the results from a 3D relativistic hydrodynamics numerical
simulation based on the parameters given for the jet by Lobanov & Zensus
(2001), and one in which the effects of jet precession and the injection of
discrete components have been taken into account. We compare the model with the
structures observed in 3C 273 using very long baseline interferometry and
constrain the basic properties of the flow. We find growing perturbation modes
in the simulation with similar wavelengths to those observed, but with a
different set of wave speeds and mode identification. If the observed longest
helical structure is produced by the precession of the flow, longer precession
periods should be expected. Our results show that some of the observed
structures could be explained by growing Kelvin-Helmholtz instabilities in a
slow moving region of the jet. However, we point towards possible errors in the
mode identification that show the need of more complete linear analysis in
order to interpret the observations. We conclude that, with the given viewing
angle, superluminal components and jet precession cannot explain the observed
structures.

27
The categories of this paper are: comp-gas
19
The categories of this paper are: eess
1
The categories of this paper are: cs
29
The categories of this paper are: funct-an
8
The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys
33
The categories of this paper are: plasm-ph
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
15
The categories of this paper are: nucl-ex
26
The categories of this paper are: bayes-an
23
The categories of this paper are: solv-int
11
The categories of this paper are: hep-lat
37
The categories of this paper are: supr-con
7
The categories of this paper are: hep-th