Clean Optical Spectrum of the Radio Jet of 3C 120

Abstract

We present integral field spectroscopy (IFS) of the central region of 3C 120. We have modeled the nuclear and host galaxy three-dimensional spectra using techniques normally applied to imaging, decoupling both components and obtaining a residual data cube. Using this residual data cube, we detected the extended emission line region associated with the radio jet. We obtained, for the first time, a clean spectrum of this region and found compelling evidence of a jet-cloud interaction. The jet compresses and splits the gas cloud, which is ionized by the active galactic nucleus (AGN) and/or by the strong local UV photon field generated by a shock process. We cannot confirm the detection of an extended emission line region associated with the counterjet reported by Axon and coworkers.