Feeding versus feedback in active galactic nuclei from near-infrared integral field spectroscopy – X. NGC 5929

Abstract

We present near-infrared emission-line flux distributions, excitation and kinematics, as well as stellar kinematics, of the inner 520 × 520 pc2 of the Seyfert 2 galaxy NGC 5929. The observations were performed with Gemini’s Near-Infrared Integral Field Spectrograph (NIFS) at a spatial resolution of ∼20 pc and spectral resolution of 40 kms−1 in the J and Kl bands. The flux distributions of H2, [FeII], [P II] and H recombination lines are extended over most of the field of view, with the highest intensity levels observed along PA = 60/240◦, and well correlated with the radio emission. The H2 and [Fe II] line emission originated in thermal processes, mainly due to heating of the gas by X-rays from the central active galactic nucleus (AGN). The contribution of shocks due to the radio jet is observed at locations co-spatial with the radio hotspots at 0.50 arcsec north-east and 0.60 arcsec south-west of the nucleus, as evidenced by the emission-line ratio and gas kinematics. The stellar kinematics shows rotation with an amplitude at 250 pc from the nucleus of ∼200 km s−1 after correcting for the inferred inclination of 18.3◦. The stellar velocity dispersion obtained from the integrated K-band spectrum is σ∗ = 133 ± 8 kms−1, which implies a mass for the supermassive black hole of M• = 5.21.6 −1.2 × 107M , using the M•–σ∗ relation. The gas kinematics present three components: (1) gas in the plane of the galaxy in counter-rotation relative to the stars; (2) an outflow perpendicular to the radio jet that seems to be due to an equatorial AGN outflow; and (3) turbulence of the gas observed in association with the radio hotspots, supporting an interaction of the radio jet with the gas of the disc. We estimated the masses of ionized gas and warm molecular gas to be ∼1.3 × 106M and ∼470M , respectively.