Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The photometric structure of the inner Galaxy   The light distribution in the inner few kiloparsecs of the Milky Way is
recovered non-parametrically from a dust-corrected near-infrared COBE/DIRBE
surface brightness map of the inner Galaxy. The best fits to the photometry are
obtained when the Sun is assumed to lie $\sim14\pm4\pc$ below the plane. The
recovered density distributions clearly show an elongated three-dimensional
bulge set in a highly non-axisymmetric disk. In the favoured models, the bulge
has axis ratios $1{:}0.6{:}0.4$ and semi-major axis length $\sim2\kpc$. Its
nearer long axis lies in the first quadrant. The bulge is surrounded by an
elliptical disk that extends to $\sim2\kpc$ on the minor axis and $\sim3.5\kpc$
on the major axis. In all models there is a local density minimum $\sim2.2\kpc$
down the minor axis. The subsequent maximum $\sim3\kpc$ down the minor axis
(corresponding to $l\simeq-22\deg$ and $l\simeq 17\deg$) may be associated with
the Lagrange point L$_4$. From this identification and the length of the
bulge-bar, we infer a pattern speed $\Omega_b\simeq 60-70\kms\kpc^{-1}$ for the
bar. Experiments in which pseudo-data derived from models with spiral structure
were deprojected under the assumption that the Galaxy is either eight-fold or
four-fold symmetric, indicate that the highly non-axisymmetric disks recovered
from the COBE data could reflect spiral structure within the Milky Way if that
structure involves density contrasts greater than $\gta 3$ at NIR wavelengths.
These experiments indicate that the angle $\phi_0$ between the Sun--centre line
and a major axis of the bulge lies near $20\deg$.

32
The categories of this paper are: atom-ph
19
The categories of this paper are: eess
14
The categories of this paper are: math-ph
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
8
The categories of this paper are: hep-ex
4
The categories of this paper are: cond-mat
7
The categories of this paper are: hep-th
31
The categories of this paper are: ao-sci
15
The categories of this paper are: nucl-ex
10
The categories of this paper are: q-bio
34
The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
35
The categories of this paper are: mtrl-th