Paper detail

Gamma-ray-emitting quasar 0202$+$149: a CSS revisited

PKS 0202$+$149 is a low-power radio source with blazar-like $γ$-ray AGN characteristics and its properties and classification are investigated in relation to its $γ$-ray characteristics. It shows a hint of low frequency turnover at about 200 MHz. Radio imaging data of 0202$+$149 at different frequencies show differing morphologies on both kilo-parsec (kpc) and parsec (pc) scales. The overall source shows a triple structure of core and double lobes with a total projected size of $\sim$1.3 kpc. The compact source structure of 0202+149 is reminiscent of a compact steep spectrum (CSS) source. At pc scales a core-jet structure extends $\sim$25 pc (in projection) at a position angle perpendicular to the kpc-scale structure. The curved pc-scale structure with jet and inner lobe suggests that the CSS nuclear activity has recently re-started although its power has been decreasing, while the kpc-scale lobes are relics of earlier activity. A maximum apparent superluminal motion of $\sim16\,c$ is detected in the jet components, indicating a highly relativistic jet flow. The brightness temperature of the core is lower than the average value found for highly-beamed $γ$-ray AGN, indicating a lower radio power and a relatively lower Doppler boosting factor. The CSS radio classification indicates that blazar-like $γ$-ray properties can also be manifested in low-power CSS radio sources with appropriate jet and beaming properties.