The X-ray obscuration and the origin of the high-energy emission in young radio sources
The early jet-ISM feedback can be studied in depth in Compact Symmetric Objects (CSOs), which have the radio lobe emission on both sides of an active nucleus and the projected radio size LS < 1 kpc. We present the radio-to-gamma-ray SED modeling of four CSOs, which are among the nearest (z < 0.2) and youngest (age < 450 yr) CSOs known to date: PKS 1718-649, a gamma-ray loud and X-ray unobscured source, and three gamma-ray quiet CSOs with X-ray absorption NH > 10^23 cm^-2. The extent of their radio lobes, LS < 25 pc, is comparable with that of the obscuring tori observed with ALMA in a number of AGN. We show that in the framework of the expanding radio lobe model, the mix of the Inverse Compton (IC) scattering of the IR and UV photons off the ultra-relativistic lobe electrons is able to account for the gross of the CSO X-ray emission. We report on a correlation between the radio slope and X-ray NH, which explains the gamma-ray quietness of the CSOs with high NH. Conversely, the gamma-rays detected with Fermi/LAT from PKS 1718-649 can be modeled well with the IC scattering of the UV photons. Our results indicate an intriguing interplay between the central ISM and the properties of the young radio lobe electrons.