Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The unified model of compact radio sources   We propose the unified model of compact radio sources, i.e. of pulsars, maser
sources, and active galactic nuclei. The unification is based on the wavelength
dependence of radio source size. It is shown that the compact sources are
characterized by a maser amplification of thermal radio emission. The density,
temperature, and magnetic field profiles of compact sources are discussed.

3
The categories of this paper are: physics
26
The categories of this paper are: bayes-an
16
The categories of this paper are: stat
32
The categories of this paper are: atom-ph
21
The categories of this paper are: adap-org
9
The categories of this paper are: nlin
1
The categories of this paper are: cs
36
The categories of this paper are: cmp-lg
12
The categories of this paper are: nucl-th
29
The categories of this paper are: funct-an
7
The categories of this paper are: hep-th
28
The categories of this paper are: alg-geom
30
The categories of this paper are: q-alg
4
The categories of this paper are: cond-mat
25
The categories of this paper are: patt-sol
22
The categories of this paper are: chao-dyn