Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: An Effective Selection Method for Low-Mass Active Black Holes and First
  Spectroscopic Identification
18
The categories of this paper are: econ
19
The categories of this paper are: eess
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
7
The categories of this paper are: hep-th
5
The categories of this paper are: gr-qc
23
The categories of this paper are: solv-int
27
The categories of this paper are: comp-gas
14
The categories of this paper are: math-ph
35
The categories of this paper are: mtrl-th
22
The categories of this paper are: chao-dyn
9
The categories of this paper are: nlin
2
The categories of this paper are: math
32
The categories of this paper are: atom-ph
26
The categories of this paper are: bayes-an
3
The categories of this paper are: physics