The Jet of FSRQ PKS~1229$-$02 and its Misidentification as a $\gamma$-ray AGN

Abstract

Flat-spectrum radio quasar PKS~1229$-$02 with a knotty and asymmetric radio morphology was identified as the optical and radio counterpart of a $\gamma$-ray source. In this paper, we study the properties, e.g. morphology, opacity, polarization and kinematics of the jet in PKS~1229$-$02 using radio interferometry. With our results, we find that the knotty and asymmetric morphology of this source may probably shaped by the interaction between its anterograde jet and the nonuniform dense ambient medium. By reproducing a Spectral Energy Distribution of PKS~1229$-$02 with the obtained kinematic parameters, we find that the relativistic beaming effect in PKS~1229$-$02 is not strong enough to produce the reported $\gamma$-ray emission, i.e. PKS~1229$-$02 may not be a $\gamma$-ray AGN. The misidentification may probably due to the poor spatial resolution of the $\gamma$-ray detector of the previous generation.