First results from the JWST Early Release Science Program Q3D: AGN photoionization and shock4 ionization in a red quasar at z = 0.45

Red quasars, often associated with potent [OIII] outflows on both galactic and circumgalactic scales, may play a pivotal role in galactic evolution and black hole feedback. In this work, we explore the [FeII] emission in one such quasar at redshift z = 0.4352, F2M J110648.32+480712.3, using the integral field unit (IFU) mode of the Near Infrared Spectrograph (NIRSpec) aboard the James Webb Space Telescope (JWST). Our observations reveal clumpy [FeII] gas located to the south of the quasar. By comparing the kinematics of [FeII] and [OIII], we find that the clumpy [FeII] gas in the southeast and southwest aligns with the outflow, exhibiting similar median velocities up to v_50 ~ 1200 km/s and high velocity widths W_80 > 1000 km/s. In contrast, the [FeII] gas to the south shows kinematics inconsistent with the outflow, with W_80 ~ 500 km/s, significantly smaller than the [OIII] at the same location, suggesting that the [FeII] may be confined within the host galaxy. Utilizing standard emission-line diagnostic ratios, we map the ionization sources of the gas. According to the MAPPINGS III shock models for [FeII]/Pabeta, the regions to the southwest and southeast of the quasar are primarily photoionized. Conversely, the [FeII] emission to the south is likely excited by shocks generated by the back-pressure of the outflow on the galaxy disk, a direct signature of the impact of the quasar on its host.