Chandra observations of the hybrid morphology radio sources 3C 433 and 4C 65.15: FR IIs with asymmetric environments

We present Chandra observations of the hybrid morphology radio sources 3C 433 and 4C 65.15, two members of the rare class of objects possessing an FR I jet on one side of the core and an FR II lobe on the other. The X-ray spectrum of 3C 433 shows intrinsic absorption (with a column density of N_H ≃ 8 × 10²² cm^-2), such as is typical of FR II narrow-line radio galaxies. There is excess X-ray emission below 2 keV containing contributions from diffuse soft X-ray emission (likely hot gas with kT ∼ 1.2 keV) as well as from the nucleus. The core of 3C 433 is extended in hard X-rays, presumably due to X-ray emission from the inner-jet knot on the FR I side that is apparent in the radio map. It is possible that the X-ray emission from this inner-jet knot is absorbed by the dust known to be present in the host galaxy. The spectrum of 4C 65.15 can be modeled with a simple power law with perhaps mild intrinsic absorption (N_H ≃ 1.3 × 10²¹ cm^-2). X-ray emission is detected at the bend in the FR I jet. This X-ray jet emission lies above the extrapolation from the high-frequency radio synchrotron emission and has a spectral slope flatter than α_rx, indicating that the jet spectral energy distribution is concave as with other FR II quasar jets. Both 3C 433 and 4C 65.15 have unabsorbed X-ray luminosities, radio luminosities, and optical spectra typically seen in comparable sources with FR II morphologies. Presumably, the FR I structure seen on one side in these hybrid sources is generated by a powerful jet interacting with a relatively dense environment.