Matteo Guainazzi

We present results from a comprehensive multiwavelength monitoring campaign of the changing-look active galactic nucleus 1ES 1927+654 during the onset and evolution of a relativistic radio jet ∼(2022 May–2025 August), using observations from XMM-Newton, Swift, Telescopio Nazionale Galileo (TNG), the Zwicky Transient Facility (ZTF), Very Large Array (VLA), and Very Long Baseline Array (VLBA). The soft X-ray emission lines at ∼0.56 keV and ∼1 keV have appeared with variable strength and width during the formation of the nascent jet. We note that the ∼1 keV feature has been persisting since the post-2017 flare phase. We also report the detection of a broad (∼800 eV) FeK emission feature at (6–7) keV in the ∼70 ks stacked EPIC-pn spectra, marking the first such detection, which historically was lacking in this source. The joint spectral fitting of XMM-Newton EPIC-pn and Reflection Grating Spectrometer (RGS) data reveals the presence of ionized absorbers in 2022 ( log ξ / erg cm s − 1 ∼ 1.5 ± 0.3 , N _H ∼ 2.5 ± 0.9 × 10 ²⁰ cm ⁻² ), but weaker than that detected during the high accretion state in 2018 (Eddington ratio, λ _Edd > 1). The absorption features further weakened in 2023–2025 and were marginally detectable ( N _H ≤ 10 ²⁰ cm ⁻² ). The entire scenario is suggestive of a real-time transition of the accretion flow (from λ _Edd > 1 to λ _Edd ∼ 0.3) during which the winds become weaker and the jet starts to form and evolve. Furthermore, both the soft X-ray (0.3–2) keV and 5 GHz radio fluxes, which increased by factors of ∼10 and ∼60, respectively, since 2022, have recently plateaued at elevated levels, indicating a stabilized accretion disk, corona, and jet configuration.

The X-ray Mirror Assemblies (XMAs) on board the X-ray Imaging and Spectroscopy Mission (XRISM) underwent dedicated in-flight calibration during the early phase of the mission to ensure high-precision imaging and spectroscopic performance. This paper presents the in-flight determination of the Xtend-XMA optical axis and the quantitative evaluation of diffuse stray light characteristics utilizing these calibration datasets. First, by analyzing multi-pointing observations of the galaxy cluster Abell 2029, we developed an asymmetric vignetting model that accounts for the intrinsic structural boundaries of the mirror quadrants, successfully eliminating a severe energy-dependent systematic bias inherent in conventional symmetric models. The newly derived reference optical axis at (DETX, DETY) = (730.1, 727.5) significantly reduces the alignment separation from the in-flight aimpoint from the initial 5300 to less than 9 00. Second, dedicated 600 off-axis observations of the Crab Nebula were utilized to characterize the XMA’s stray light performance under a worst-case azimuthal configuration. The observed stray light in the Xtend wide-field images was successfully decomposed into a soft precollimator-blade scattering component (∼1 keV) and a harder secondary-only single-reflection component (up to 5 keV). The compact Resolve Field of View shows no detectable stray light under the current gate-valve (GV) closed state, which is consistent with the non-X-ray background (NXB). On the other hand, predictive spectral simulations indicate that the secondary-only component will surpass the NXB in the 1–3 keV band once the GV is opened, reaching approximately four times the NXB level near 1.5 keV.

The X-ray source in active galactic nuclei (AGNs) is commonly referred to as the corona by analogy to stellar coronae. The similarities between the two suggest that the heating mechanism of AGN coronae is magnetic reconnection—as in cool stars—but this has not yet been directly observed. This work presents the first observational evidence for a magnetic reconnection flare in an AGN corona. We report on a flare in NGC 3783, which was observed with XRISM/Xtend and XMM-Newton/EPIC exhibiting distinct temporal evolution in soft (2.0 keV) X-rays. An ultrafast outflow (UFO) was detected during the event. The flare features the Neupert effect—a temporal signature of the hard light curve correlating with the time derivative of the soft light curve, which shows that the flare is powered by magnetic reconnection. The Neupert effect is widely observed in the Sun, with coronal mass ejections (CMEs) playing a role analogous to the UFO. We derive an upper limit of 30 R _g on the height of the magnetic loop from which the flare originates. Using the UFO measured properties to characterize the magnetic field, we obtain B > 1.3 × 10 ⁴ G for the field annihilated during the flare from total energy considerations, and B ≈ 500 G for the momentary magnetic field during reconnection from a dynamical consideration.

Context. Ultra-fast outflows (UFOs) are mildly relativistic (outflow velocity v _out > 0.1c) nuclear winds detected as blueshifted absorption lines from highly ionized, dense gas in the X-ray spectra of active galactic nuclei (AGNs). The AGN feedback mechanism is believed to be powered by these outflows, which can inject a large amount of energy and momentum into the surrounding interstellar medium, shaping the coevolution of the AGNs and their host galaxies. Aims. We performed a systematic search and rigorous statistical assessment of the presence of UFOs in the 7 − 12 keV band, in a sample of bright local AGNs. This study also aims to understand whether the presence and characteristics of UFOs depend on the state of the sources, by studying the relations between the incidence of UFOs and the accretion properties of AGNs. Methods. We collected X-ray spectroscopic flux-limited XMM-Newton data of 33 observations of local ( z < 0.2) type 1 AGNs. We modeled their spectra in the 2 − 12 keV band using a combination of direct-continuum and reflection components and searched for absorption features. This represents the first systematic search for UFOs up to 12 keV. We performed Monte Carlo (MC) simulations to assess the statistical significance of the detected lines. Results. We report strong detections of UFOs in six sources of the sample at the ≥95% confidence level via MC simulations, corresponding to a fraction of ∼18% in our sample. From the observed energies of each absorption line, we evaluated the respective wind velocities, which in some cases exceed 40% of the speed of light. The velocity distribution found in this work is therefore shifted to higher energies than those found in previous searches for UFOs in local sources, which were limited to 10 keV. Moreover, our analysis shows no correlation between the accretion properties of the super massive black holes (SMBHs) and the presence of winds. Finally, the comparison with previous studies of nuclear winds in local AGNs highlights the temporal variability of UFOs.

Emission lines that “echo” variations in the ionizing flux produced close to black holes are powerful probes of the central engine. In the Seyfert-1.5 galaxy NGC 4151, high-resolution X-ray spectra and time lags in low-resolution X-ray data suggest that part of the narrow Fe K _α line originates close to the optical broad line region (BLR). We report on a sequence of nine XRISM observations of NGC 4151, obtained every other day in 2024. Swift monitoring was undertaken to sample the driving flux before, during, and after the XRISM sequence. Using suitable line kernels, we measure a mean BLR component width of σ = 5.36 ± 0.48 × 10 ³ km s ⁻¹ . Modeling the Swift continuum and XRISM line flux trends gives a lag of τ = 3 . 5 − 1.7 + 2.8 days ( r = 3 . 6 − 1.7 + 3.0 × 1 0 3 G M / c 2 for M _BH = 1.7 × 10 ⁷ M _⊙ ), significant at the 2 σ level via Monte Carlo simulations and consistent with prior measurements and direct spectral fits. This lag implies a black hole mass of M BH / f X = 2 . 0 − 1.0 + 1.4 × 1 0 7 M ⊙ , where f _X is a geometrical factor. A standard optical value for this factor gives a mass that is nominally higher than typical H β mass estimates, but formally consistent. Our results suggest that XRISM can measure lags and black hole masses in both unobscured and obscured active galactic nuclei (AGN).

We present a study of an X-ray-selected sample of active galactic nuclei (AGN) in pairs at projected spatial separations 1 < r _p /kpc < 100 at z < 0.1, using XMM-Newton and Chandra data. We derived the pair sample from an initial pool of approximately 2000 X-ray-selected AGN, and is composed of both AGN-AGN pairs (so-called dual AGN) and AGN-galaxy pairs. From this selection, we find that approximately 10% of AGN reside in pairs, and about 4% are paired with another AGN. We performed a detailed X-ray and SDSS optical spectral analysis for AGN in dual systems and X-ray analysis for AGN in AGN-galaxy pairs, to characterise their absorption properties and investigate the possible triggering mechanisms. We then investigated how obscuration, luminosity, and Eddington ratio depend on projected separation r _p . Amongst all AGN in pair, we find that ∼55% are obscured (with hydrogen column density N _H > 10 ²² cm ⁻² ), amongst which ∼6% are Compton-thick ( N _H > 10 ²⁴ cm ⁻² ). The fraction of absorbed AGN is significantly higher in late-stage mergers ( r _p < 30 kpc) compared to early-stage mergers ( r _p > 60 kpc). Amongst the AGN pairs, we also observe an average excess relative to a control sample of inactive galaxies in pairs, and this excess significantly increases with decreasing r _p , but only for obscured AGN. Finally, in dual-AGN systems, both the bolometric luminosity and the Eddington ratio of the less massive black hole in the pair increase as the separation decreases. These findings suggest that mergers may play an important role in triggering AGN accretion and activity.

Context. 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. Aims. 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 Fe XXV and Fe XXVI emission. Methods. We analyzed an XRISM/Resolve observation of NGC 1068, focusing on the Fe K α and Fe K β fluorescent lines and on the Fe XXV and Fe XXVI 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. Results. The centroid energies of the Fe K α and Fe K β lines tightly constrain the emitting material to be neutral or near neutral. The observed Fe K β /K α ratio, together with the stringent upper limit on the Compton shoulder (≲8−11% of the core flux), disfavor reflection dominated by a homogeneous classical Compton-thick medium, indicating that most of the neutral Fe K α emission arises in optically thin or moderately Compton-thick gas. The Fe XXV and Fe XXVI emission lines exhibit remarkably large velocity widths, of several thousand km s ⁻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. Conclusions. 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.

The Seyfert 1 galaxy NGC 3783 hosts a multi-phase warm absorber (WA) that has been extensively studied in the X-ray band. High-resolution spectra from 2000−2001 revealed a complex outflow with multiple ionization and velocity components. Two decades later, new XMM-Newton and XRISM observations allow us to investigate the long-term evolution of these outflows. We performed joint spectral modelling of the XMM-Newton /RGS and XRISM/Resolve time-averaged spectra using the pion photoionization code within SPEX . We derived the ionization parameter, column density, turbulent velocity, and outflow velocity for each absorption component, and investigated their thermal stability and absorption measure distribution (AMD) to characterize the physical and dynamical properties of the WA in NGC 3783 in 2024. We compared these results with the 2000−2001 epoch to assess long-term variability, stability, and possible changes in the absorber population. We identify eight WA components spanning log ξ = 1.08 − 3.38 and outflow velocities of 480−1230 km s ⁻¹ . The ranges of column densities and turbulent velocities remain broadly consistent with the WAs from 2000−2001, but the earlier data contained more low-ionization, high-velocity components. The total column density of all the outflows in 2024 is 1.5 times larger than in 2000−2001, which means that it has been replenished by fresh material. The dominant unresolved transition array (UTA) absorber (component B3) has increased its column density by a factor of three while maintaining a similar ionization parameter. The WAs in NGC 3783 have undergone significant structural and dynamical evolution over the past 24 years.

NGC 4151 is the brightest Seyfert 1 galaxy in the band of the Resolve calorimeter aboard XRISM. It has been observed on 14 occasions. Herein, we report on an analysis of its time-averaged 893 ks spectrum. The narrow Fe K α emission-line complex requires contributions from the torus and optical broad-line region (BLR). Models assuming an emissivity index of q = 2 for these components are statistically preferred, consistent with a “bowl” geometry for the central engine. A smooth red wing of these line components is consistent with Compton scattering from bound electrons, signaling the presence of dust in the base of the BLR and in the torus. The data statistically prefer relativistic reflection from a disk with an inner radius of r = 3 . 2 − 2.0 + 3.5 G M / c 2 , and an inclination of θ = 29 . 7 − 0.4 + 0.5 degrees. The Fe K edge at 7.1 keV is best modeled with contributions from multiple charge states, consistent with cool, kT ≃ 5 eV collisional gas or photoionized gas. Slow “warm absorber” winds spanning Fe XX–XXVI , faster winds seen via Fe XXV and Fe XXVI lines, and ultra-fast outflows (UFOs) are detected simultaneously. The warm absorbers are “failed” winds; the data constrain their radius, density, filling factor, and distribution. For the most conservative volume filling factors, the UFOs may not be able to halt star formation. However, the UFOs may generate galaxy-altering feedback for larger filling factors and/or during certain intervals.