Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: The Supermassive Black Hole at the Heart of Centaurus A: Revealed by
  Gas- and Stellar Kinematics
27
The categories of this paper are: comp-gas
4
The categories of this paper are: cond-mat
37
The categories of this paper are: supr-con
28
The categories of this paper are: alg-geom
18
The categories of this paper are: econ
8
The categories of this paper are: hep-ex
23
The categories of this paper are: solv-int
33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci
22
The categories of this paper are: chao-dyn
11
The categories of this paper are: hep-lat
15
The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
2
The categories of this paper are: math
19
The categories of this paper are: eess
32
The categories of this paper are: atom-ph