An outflow perpendicular to the radio jet in the Seyfert nucleus of NGC 5929

Abstract

We report the observation of an outflow perpendicular to the radio jet in near-infrared integral field spectra of the inner 250 pc of the Seyfert 2 galaxy NGC 5929. The observations were obtained with the Gemini Near-infrared Integral Field Spectrograph at a spatial resolution of ∼20 pc and spectral resolution of R ≈ 5300 and reveal a region ∼50 pc wide crossing the nucleus and extending by ∼300 pc perpendicularly to the known radio jet in this galaxy. Along this structure—which we call the south-east–north-west (SE–NW) strip—the emission line profiles show two velocity components, one blueshifted and the other redshifted by −150 km s-ˡ and 150 km s-ˡ, respectively, relative to the systemic velocity. We interpret these two components as being due to an outflow perpendicular to the radio jet, which is supported by low-frequency radio emission observed along the same region. We attribute this feature to the interaction of ambient gas with an “equatorial outflow” predicted in recent accretion disk and torus wind models. Perpendicularly to the SE–NW strip, thus approximately along the radio jet, single-component profiles show blueshifts of ≈−150 km s-ˡ to the north-east and similar redshifts to the south-west, which can be attributed to gas counter-rotating relative to the stellar kinematics. More double-peaked profiles are observed in association with the two radio hot spots, attributed to interaction of the radio jet with the surrounding gas.