Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Gaia and the dynamics of the Galaxy   Gaia is an ambitious ESA space mission which will provide photometric and
astrometric measurements with the accuracies needed to produce a kinematic
census of almost one billion stars in our Galaxy. These data will revolutionize
our understanding of the dynamics of the Milky Way, and our knowledge of its
detailed gravitational potential and mass distribution, including the putative
dark matter component and the non-axisymmetric features such as spiral arms.
The Gaia mission will help to answer various currently unsettled questions by
using kinematic information on both disk and halo stellar populations. Among
many others: what does the rotation curve of the outer Galaxy look like? How
far from axisymmetry and equilibrium is the Galaxy? What are the respective
roles of hierarchical formation and secular evolution in shaping the Galaxy and
its various components? Are the properties of the Galaxy in accordance with
expectations from the standard model of cosmology?

17
The categories of this paper are: q-fin
13
The categories of this paper are: quant-ph
19
The categories of this paper are: eess
26
The categories of this paper are: bayes-an
37
The categories of this paper are: supr-con
4
The categories of this paper are: cond-mat
7
The categories of this paper are: hep-th
29
The categories of this paper are: funct-an
16
The categories of this paper are: stat
28
The categories of this paper are: alg-geom
10
The categories of this paper are: q-bio
11
The categories of this paper are: hep-lat
23
The categories of this paper are: solv-int
20
The categories of this paper are: acc-phys
32
The categories of this paper are: atom-ph
2
The categories of this paper are: math