Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Megamaser Disks Reveal a Broad Distribution of Black Hole Mass in Spiral
  Galaxies
29
The categories of this paper are: funct-an
19
The categories of this paper are: eess
18
The categories of this paper are: econ
25
The categories of this paper are: patt-sol
27
The categories of this paper are: comp-gas
24
The categories of this paper are: dg-ga
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph
11
The categories of this paper are: hep-lat
0
The categories of this paper are: hep-ph
10
The categories of this paper are: q-bio
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
32
The categories of this paper are: atom-ph
7
The categories of this paper are: hep-th