Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Radio variability properties for radio sources   In this paper, we used the database of the university of Michigan Radio
Astronomy Observatory (UMRAO) at three (4.8 GHz, 8.0 GHZ, and 14.5 GHz) radio
frequency to analyze the radio light curves by the power spectral analysis
method in search of possible periodicity. The analysis results showed that the
radio sources display astrophysically meaningful periodicity ranging from 2.2
to 20.8 years in their light curves at the three frequencies. We also
calculated the variability parameters and investigated the correlations between
the variability parameter and the flux density. For the variability parameters,
we found that the parameters at higher frequency are higher than those in the
lower frequency. In addition, the variability parameters of BL Lacertae objects
are larger than those of flat-spectrum radio quasars. suggesting that they are
more variable than flat spectrum radio quasars.

13
The categories of this paper are: quant-ph
17
The categories of this paper are: q-fin
8
The categories of this paper are: hep-ex
23
The categories of this paper are: solv-int
30
The categories of this paper are: q-alg
10
The categories of this paper are: q-bio
34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas
9
The categories of this paper are: nlin
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
19
The categories of this paper are: eess
33
The categories of this paper are: plasm-ph
29
The categories of this paper are: funct-an
25
The categories of this paper are: patt-sol
32
The categories of this paper are: atom-ph