Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: 3D self-consistent N-body barred models of the Milky Way: II. Gas
  dynamics   The gas dynamics in the Galactic disc is modeled by releasing an initially
axisymmetric SPH component in a completely self-consistent and symmetry-free 3D
N-body simulation of the Milky Way in which the stellar components display a
COBE-like bar. The density centre of the stellar bar wanders around the centre
of mass and the resulting gas flow is asymmetric and non-stationary,
reproducing the HI and CO l-V diagrams only at specific times and thus
suggesting a transient nature of the observed inner gas kinematics.
  The best matching models allow a new and coherent interpretation of the main
features standing out of the l-V data within the bar region. In particular, the
l-V traces of the prominent offset dustlanes leading the bar major axis in
early-type barred spirals can be unambiguously identified, and the 3-kpc arm
and its non-symmetric galactocentric opposite counterarm are the inner
prolongations of disc spiral arms passing round the bar and joining the
dustlanes at very different galactocentric distances. Bania's clump 1 and 2,
and another velocity-elongated feature near l= 5.5 deg, are interpreted as gas
lumps crossing the dustlane shocks. The terminal velocity peaks near l=+/- 2.5
deg are produced by gas along the dustlanes and not by the trace of the cusped
x1 orbit, which passes farther away from the Galactic centre. According to
these models and to related geometrical constraints, the Galactic bar must have
an inclination angle of 25+/-4 deg, a corotation radius of 4.0-4.5 kpc and a
face-on axis ratio b/a=0.6.

22
The categories of this paper are: chao-dyn
12
The categories of this paper are: nucl-th
10
The categories of this paper are: q-bio
7
The categories of this paper are: hep-th
24
The categories of this paper are: dg-ga
36
The categories of this paper are: cmp-lg
8
The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
23
The categories of this paper are: solv-int
11
The categories of this paper are: hep-lat
17
The categories of this paper are: q-fin
19
The categories of this paper are: eess
2
The categories of this paper are: math
33
The categories of this paper are: plasm-ph
4
The categories of this paper are: cond-mat