Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Investigation on Young radio AGNs based on SDSS spectroscopy   The Gigahertz Peaked Spectrum (GPS) sources, Compact Steep Spectrum (CSS)
radio sources, and High Frequency Peakers (HFP) radio sources are thought to be
young radio AGNs, at the early stage of AGN evolution. We investigated the
optical properties of the largest sample of 126 young radio AGNs based on the
spectra in SDSS DR12. We find the black hole masses $M_{\rm BH}$ range from
$10^{7.32}$ to $10^{9.84}$ $\rm M_{sun}$, and the Eddington ratios $R_{\rm
edd}$ vary from $10^{-4.93}$ to $10^{0.37}$, suggesting that young radio AGNs
have various accretion activities and not all are accreting at high accretion
rate. Our young radio sources generally follow the evolutionary trend towards
large-scale radio galaxies with increasing linear size and decreasing accretion
rate in the radio power - linear size diagram. The radio properties of low
luminosity young radio AGNs with low $R_{\rm edd}$ are discussed. The line
width of [O III] $\lambda5007$ core ($\sigma_{\rm [O III]}$) is found to be a
good surrogate of stellar velocity dispersion $\sigma_{\ast}$. The radio
luminosity $L_{\rm 5GHz}$ correlates strongly with [O III] core luminosity
$L_{\rm [O III]}$, suggesting that radio activity and accretion are closely
related in young radio sources. We find one object that can be defined as
narrow-line Seyfert 1 galaxies (NLS1s), representing a population of young AGNs
both with young jet and early accretion activity. The optical variabilities of
15 quasars with multi-epoch spectroscopy were investigated. Our results show
that the optical variability in young AGN quasars presents low variations
($\leqslant60\%$) similar to the normal radio-quiet quasars.

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The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga
4
The categories of this paper are: cond-mat
35
The categories of this paper are: mtrl-th
3
The categories of this paper are: physics
28
The categories of this paper are: alg-geom
1
The categories of this paper are: cs
31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
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The categories of this paper are: hep-ex
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The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: acc-phys
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The categories of this paper are: math-ph
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The categories of this paper are: q-bio