| Résumé | Context. Studying the distribution and properties of ionised gas in outflows driven by active galactic nuclei (AGN) is crucial for understanding the feedback mechanisms at play in extragalactic environments. These outflows provide key insights into the regulation of star formation and the growth of supermassive black holes.
Aims. In this study, we explore the connection between ionised outflows traced by rest-frame ultra-violet (UV) absorption and optical emission lines in GS133, a Compton thick AGN at z = 3.47. We combine observations from the James Webb Space Telescope (JWST) NIRSpec Integral Field Spectrograph (IFS) with archival Very Large Telescope (VLT) VIMOS long-slit spectroscopic data, as part of the ‘Galaxy Assembly with NIRSpec IFS’ (GA-NIFS) project.
Methods. We performed a multi-component kinematic decomposition of the UV and optical line profiles to derive the physical properties of the absorbing and emitting gas in GS133.
Results. Our kinematic decomposition reveals two distinct components in the optical emission lines. The first component likely traces a rotating disc with a dynamical mass of 2 × 10¹⁰ M⊙. The second component corresponds to a galaxy-wide, bi-conical outflow, with a velocity of ∼ ± 1000 km s⁻¹ and an extension of ∼3 kpc. The UV absorption lines show two outflow components, with bulk velocities vout ∼ −900 km s⁻¹ and ∼ − 1900 km s⁻¹, respectively. This characterises GS133 as a mini-broad absorption line (mini-BAL) system. Balmer absorption lines with similar velocities are tentatively detected in the NIRSpec spectrum. Both photoionisation models and outflow energetics suggest that the ejected absorbing gas is located at 1–10 kpc from the AGN. We use 3D gas kinematic modelling to infer the orientation of the [O III] bi-conical outflow, and find that a portion of the emitting gas resides along our line of sight, suggesting that [O III] and absorbing gas clouds are partially mixed in the outflow. The derived mass-loading factor (i.e. the mass outflow rate divided by the star formation rate) of 1–10, and the kinetic coupling efficiency (i.e. the kinetic power divided by LAGN) of 0.1–1% suggest that the outflow in GS133 provides significant feedback on galactic scales. |
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