Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Spatially resolved Spectro-photometry of M81: Age, Metallicity and
  Reddening Maps
32
The categories of this paper are: atom-ph
24
The categories of this paper are: dg-ga
1
The categories of this paper are: cs
37
The categories of this paper are: supr-con
7
The categories of this paper are: hep-th
15
The categories of this paper are: nucl-ex
21
The categories of this paper are: adap-org
25
The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio
3
The categories of this paper are: physics
27
The categories of this paper are: comp-gas
9
The categories of this paper are: nlin
19
The categories of this paper are: eess
29
The categories of this paper are: funct-an
30
The categories of this paper are: q-alg
4
The categories of this paper are: cond-mat