Extended X-Ray Emission in Radio Galaxies: The Peculiar Case of 3C 305

Extended X-ray structures are common in active galactic nuclei. Here, we present the first case of a compact steep spectrum radio galaxy, 3C 305, in which the X-ray radiation appears to be associated with the optical emission line region, dominated by the [Oiii]5007. On the basis of a morphological study performed using a comparison between the X-rays, the optical, and the radio bands, we argue that the high-energy emission has a thermal nature and it is not directly linked to the radio jet and hotspots of this source. Finally, we discuss the origin of the extended X-ray structure connected with the optical emission line region following two different interpretations: as due to the interaction between matter outflows and shock-heated environment gas, or as due to gas photoionized by nuclear emission.