2024MNRAS.52710844H

We present a two-dimensional study of the gas distribution, excitation, and kinematics of the OH absorber galaxy IRAS 19154+2704 using Gemini Multi-Object Spectrograph integral field unit observations. Its continuum image shows a disturbed morphology indicative of a past or ongoing interaction. The ionized gas emission presents two kinematic components: a narrow (σ ≲ 300 km s^–1) component that may be tracing the gas orbiting in the galaxy potential and a broad (σ ≳ 500 km s^–1) component, which is produced by an active galactic nucleus (AGN)-driven outflow, with velocities reaching -500 km s^–1, which may exceed the escape velocity of the galaxy. The emission-line ratios and Baldwin-Phillips-Terlevich diagrams confirm that the gas excitation in the inner ∼2 kpc is mainly due to the AGN, while in regions farther away, a contribution from star formation is observed. We estimate a mass-outflow rate of $\dot{M}_{\rm out}=4.0\pm 2.6$ M_⊙ yr^–1 at a distance of 850 pc from the nucleus. The corresponding outflow kinetic power, $\dot{E}_{\rm out} = (2.5\pm 1.6)\times 10^{42}$ erg s^–1, is only 3 × 10^–4 L_bol (the AGN luminosity), but the large mass-outflow rate, if kept for an ∼10 Myr AGN life cycle, will expel ≈10⁸ M_⊙ in ionized gas alone. This is the sixth of a series of papers in which we have investigated the kinematics of ultra-luminous infrared galaxies, most of which are interacting galaxies showing OH megamasers. IRAS 19154 shows the strongest signatures of an active AGN, supporting an evolutionary scenario: interactions trigger AGN that fully appears in the most advanced stages of the interaction.