Optical Properties of Peaked Spectrum Radio Sources

TL;DR

This study investigates the optical characteristics of compact radio sources, revealing that they are mainly hosted by diverse galaxy types with old stellar populations and are generally gas-rich, with no significant optical-radio property correlation.

Contribution

It provides a comprehensive optical analysis of a diverse sample of peaked spectrum radio sources, highlighting their stellar populations, morphologies, and gas content, and compares different spectral classes.

Findings

Dominance of intermediate to old stellar populations.

No significant optical-radio property correlation.

Compact sources are gas-rich systems.

Abstract

In this work, we study the optical properties of compact radio sources selected from the literature in order to determine the impact of the radio-jet in their circumnuclear environment. Our sample includes 58 Compact Steep Spectrum (CSS) and GigaHertz Peaked Spectrum (GPS) and 14 Megahertz-Peaked spectrum (MPS) radio sources located at $z\leq 1$. The radio luminosity ($L_R$) of the sample varies between Log\,L$_R\sim$ 23.2 and 27.7 W\,Hz$^{-1}$. We obtained optical spectra for all sources from SDSS-DR12 and performed a stellar population synthesis using the {\sc starlight} code. We derived stellar masses (M$_\star$), ages $\langle t_\star \rangle$, star formation rates (SFR), metallicities $\langle Z_\star \rangle$ and internal reddening A$_V$ for all young AGNs of our sample. A visual inspection of the SDSS images was made to assign a morphological class for each source. Our results indicate that the sample is dominated by intermediate to old stellar populations and there is no strong correlation between optical and radio properties of these sources. Also, we found that young AGNs can be hosted by elliptical, spiral and interacting galaxies, confirming recent findings. When comparing the optical properties of CSS/GPS and MPS sources, we do not find any significant difference. Finally, the Mid-Infrared WISE colours analysis suggest that compact radio sources defined as powerful AGNs are, in general, gas-rich systems.