Powerful ionized gas outflows in the interacting radio galaxy 4C+29.30

Abstract

We investigate the ionized gas excitation and kinematics in the inner 4.3 × 6.2 kpc2 of the merger radio galaxy 4C+29.30. Using optical integral field spectroscopy with the Gemini North Telescope, we present flux distributions, line-ratio maps, peak velocities and velocity dispersion maps as well as channel maps with a spatial resolution of ≈955 pc. We observe high blueshifts of up to ∼−650 km s−1 in a region ∼1 arcsec south of the nucleus (the southern knot – SK), which also presents high velocity dispersions (∼250 km s−1), which we attribute to an outflow. A possible redshifted counterpart is observed north from the nucleus (the northern knot – NK). We propose that these regions correspond to a bipolar outflow possibly due to the interaction of the radio jet with the ambient gas. We estimate a total ionized gas mass outflow rate of M˙ out = 25.4+11.5 −7.5 M yr−1with a kinetic power of E˙ = 8.1+10.7 −4.0 × 1042 erg s−1, which represents 5.8+7.6 −2.9 per cent of the active galactic nucleus (AGN) bolometric luminosity. These values are higher than usually observed in nearby active galaxies with the same bolometric luminosities and could imply a significant impact of the outflows in the evolution of the host galaxy. The excitation is higher in the NK – that correlates with extended X-ray emission, indicating the presence of hotter gas – than in the SK, supporting a scenario in which an obscuring dust lane is blocking part of the AGN radiation to reach the southern region of the galaxy.