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 kpc 2 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 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 −1 with a kinetic power of E = 8.1 +10.7 −4.0 × 10 42 erg s −1 , which represents 5.8 +7.6 −2.9 % of the 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.