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The Gigahertz Peaked Spectrum (GPS) sources, Compact Steep Spectrum (CSS)radio sources, and High Frequency Peakers (HFP) radio sources are thought to beyoung radio AGNs, at the early stage of AGN evolution. We investigated theoptical properties of the largest sample of 126 young radio AGNs based on thespectra 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 $R_{\rmedd}$ vary from $10^{-4.93}$ to $10^{0.37}$, suggesting that young radio AGNshave various accretion activities and not all are accreting at high accretionrate. Our young radio sources generally follow the evolutionary trend towardslarge-scale radio galaxies with increasing linear size and decreasing accretionrate in the radio power - linear size diagram. The radio properties of lowluminosity young radio AGNs with low $R_{\rm edd}$ are discussed. The linewidth of [O III] $\lambda5007$ core ($\sigma_{\rm [O III]}$) is found to be agood surrogate of stellar velocity dispersion $\sigma_{\ast}$. The radioluminosity $L_{\rm 5GHz}$ correlates strongly with [O III] core luminosity$L_{\rm [O III]}$, suggesting that radio activity and accretion are closelyrelated in young radio sources. We find one object that can be defined asnarrow-line Seyfert 1 galaxies (NLS1s), representing a population of young AGNsboth with young jet and early accretion activity. The optical variabilities of15 quasars with multi-epoch spectroscopy were investigated. Our results showthat the optical variability in young AGN quasars presents low variations($\leqslant60\%$) similar to the normal radio-quiet quasars.

Investigation on Young radio AGNs based on SDSS spectroscopy