NGC 1068 has long served as the reference Compton-thick Seyfert 2 galaxy. Decades of X-ray observations have established the presence of both neutral reflection and ionized circumnuclear emission. However, the limited spectral capabilities of previous CCD and grating data in the Fe--K band have prevented a clean separation of these components, thus leaving large uncertainties on key properties, such as the optical depth, structure, and kinematics of the reprocessing and emitting regions, and on their connection to nuclear outflows and feedback. We exploited high-resolution X-ray spectroscopy to disentangle the neutral and ionized iron emission in NGC 1068; constrained the physical properties of the cold reflector through line energies, widths, fluorescence ratios, and Compton-shoulder diagnostics; and investigated the origin, kinematics, and potential feedback role of the highly ionized and emission. Fe xxv Fe xxvi We analyzed an XRISM/Resolve observation of NGC 1068, focusing on the Fe Kα and Fe Kβ fluorescent lines and on the and emission complexes. Line centroid energies, intrinsic widths, flux ratios, and constraints on the Compton shoulder were derived through local spectral fitting, and compared with atomic calculations and theoretical predictions. Fe xxv Fe xxvi The centroid energies of the Fe Kα and Fe Kβ lines tightly constrain the emitting material to be neutral or near neutral. The observed Fe Kβ/Kα ratio, together with the stringent upper limit on the Compton shoulder (łesssim8--11% of the core flux), disfavor reflection dominated by a homogeneous classical Compton-thick medium, indicating that most of the neutral Fe Kα emission arises in optically thin or moderately Compton-thick gas. The and emission lines exhibit remarkably large velocity widths, of several thousand km s Fe xxv Fe xxvi -1 . These broad profiles closely resemble the integrated optical and infrared O iii and O iv lines associated with the large-scale biconical outflow, and are naturally interpreted as the X-ray signature of a more highly ionized, faster, and more spatially confined phase of the same outflow. The iron-K emission of NGC 1068 reveals a stratified circumnuclear environment in which neutral and highly ionized components arise in physically distinct regions. The neutral Fe K fluorescence originates predominantly in optically thin or mildly Compton-thick material, despite the persistently Compton-thick line-of-sight obscuration, indicating a geometrically complex cold reprocessor. The highly ionized iron emission lines trace a fast component consistent with a bipolar outflow on parsec scales, whose large velocities and inferred energetics suggest that it may represent an efficient channel for feedback. If similar ionized outflows and reflection geometries are common in heavily obscured Seyferts, they may constitute an underappreciated aspect of feedback and circumnuclear structure in this class of sources.
Bianchi et al. (Thu,) studied this question.