Modeling the [Fe II]λ1.644μm outflow and comparison with H₂ and H+ kinematics in the inner 200 pc of NGC 1068

الأصل · EN

We map the kinematics of the inner (200 pc) narrow-line region (NLR) of the Seyfert 2 galaxy NGC 1068 using the instrument NIFS and adaptative optics at the Gemini North Telescope. Channel maps and position-velocity diagrams are presented at a spatial resolution of 10 pc and spectral resolution 5300 in the emission lines [Fe II] λ 1.644 μm, H₂ λ 2.122 μm and Brγ. The [Fe II] emission line provides a better coverage of the NLR outflow than the previously used [O III] λ 5007 emission line, extending beyond the area of the bi-polar cone observed in Brγ and [O III]. This is mainly due to the contribution of the redshifted channels to the NE of the nucleus, supporting its origin in a partial ionized zone with additional contribution from shocks of the outflowing gas with the galactic disc. We modeled the kinematics and geometry of the [Fe II] emitting gas finding good agreement with the data for outflow models with conical and lemniscate (or hourglass) geometry. We calculate a mass outflow rate 1.9⁺¹.⁹₋₀.₇ M yr⁻¹ but a power for the outflow of only 0.08% LBol. The molecular (H₂) gas kinematics is completely distinct from that of [Fe II] and Brγ, showing radial expansion in an off-centered 100 pc radius ring in the galaxy plane. The expansion velocity decelerates from 200 km/s in the inner border of the ring to approximately zero at the outer border where our previous studies found a 10 Myr stellar population.