Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The internal dynamics of very flattened normal galaxies: Stellar
  distribution functions for NGC 4697   Using the photometry and the kinematic data, part of which acquired with the
NTT, we constructed a 2-integral and a 3-integral distribution function for NGC
4697. We detected a nuclear dust lane at $3.4''$ or 0.4 kpc from the centre. A
comparison of the Lucy-deprojection method and the multi-gaussian expansion
method showed that the latter offers a number of advantages, among which a
qualitatively better fit and better controllable convergence. Futhermore, we
show that a 2-integral model cannot be excluded for as far as the Satoh
parameter $k$ is allowed to vary. The 3-integral model is based on a St\"ackel
third integral. The original potential is retained where appropriate, in order
to minimise errors due to the St\"ackel approximation. On the whole, the
3-integral model produces more satisfying results than the 2-integral model,
and is better in handling some peculiarities in the kinematic data. For both
models we show detailed contour plots for all deprojected moments up to order
2. The mass-to-light ratio appears to be a fairly well determined
$(M/L)_B=4.8h_{50}$, and is much better constrained than would be the case for
spherical anisotropic models with comparable data.

8
The categories of this paper are: hep-ex
19
The categories of this paper are: eess
33
The categories of this paper are: plasm-ph
11
The categories of this paper are: hep-lat
16
The categories of this paper are: stat
22
The categories of this paper are: chao-dyn
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
35
The categories of this paper are: mtrl-th
23
The categories of this paper are: solv-int
10
The categories of this paper are: q-bio
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
12
The categories of this paper are: nucl-th
36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con