Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Possible observational signatures of SMBHBs in their Fe K$\alpha$ line
  profiles
33
The categories of this paper are: plasm-ph
29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
3
The categories of this paper are: physics
18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys
8
The categories of this paper are: hep-ex
24
The categories of this paper are: dg-ga
26
The categories of this paper are: bayes-an
19
The categories of this paper are: eess
15
The categories of this paper are: nucl-ex
16
The categories of this paper are: stat
2
The categories of this paper are: math
4
The categories of this paper are: cond-mat
7
The categories of this paper are: hep-th