Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Optical Studies of Isolated Neutron Stars and Their Environments   The results of optical studies of Isolated Neutron Stars (INSs), their
Pulsar-Wind Nebulae (PWNe) and Pulsar Bow Shocks are reviewed and discussed.

16
The categories of this paper are: stat
26
The categories of this paper are: bayes-an
14
The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys
1
The categories of this paper are: cs
4
The categories of this paper are: cond-mat
21
The categories of this paper are: adap-org
5
The categories of this paper are: gr-qc
31
The categories of this paper are: ao-sci
3
The categories of this paper are: physics
15
The categories of this paper are: nucl-ex
32
The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat