Explore the vast range of titles available.

The bulk of X-ray spectroscopic studies of active galactic nuclei (AGN) are focused on local (\\(z < 0.1\\)) sources with low-to-moderate (\\(< 0.3\\)) Eddington ratio (\\(\\lambda_\\mathrm{Edd}\\)). It is then mandatory to overcome this limitation and improve our understanding of highly accreting AGN. In this work we present the preliminary results from the analysis of a sample of \\(\\sim70\\) high-\\(\\lambda_\\mathrm{Edd}\\) radio-quiet AGN at \\(0.06 \\leq z \\leq 3.3\\), based on the 10th release of the XMM-Newton serendipitous source catalogue, that we named as XMM-Newton High-Eddington Serendipitous AGN Sample (X-HESS). Almost \\(\\sim35\\%\\) of the X-HESS AGN have multi-epoch archival observations and \\(\\sim70\\%\\) of the sources can rely on simultaneous OM optical data. First results reveal sources showing signatures of ultra-fast outflows and remarkable long- and short-term X-ray flux variations. Indeed in J095847.88+690532.7 (\\(z \\sim 1.3\\)), one of the most densely monitored objects hosting a $\\sim$$10^9\\,M_\\odot\\( supermassive black hole, we discovered a variation of the soft X-ray flux by a factor of > 2 over approximately one week (rest-frame). Large variations in the power-law continuum photon index \\)\\Gamma\\( are also observed, questioning expectations from previously reported \\)\\Gamma - \\lambda_\\mathrm{Edd}\\( relations, for which \\)\\Gamma \\geq 2\\( would be a ubiquitous hallmark of AGN with \\)\\lambda_\\mathrm{Edd} \\sim 1$.

We discuss the origin of a very unusual spectral structure observed in the Fe-K band of the Seyfert galaxy Mrk 1513, a local (\\(z\\)=0.063) active galactic nucleus (AGN) that is efficiently accreting matter onto its central supermassive black hole (\\(L_{\\rm bol}/L_{\\rm Edd}\\sim\\)0.5). We consider the highest quality X-ray observation of this source available to date, performed in 2003 by XMM-Newton. The hard X-ray spectrum is characterised by a remarkable spectral drop at \\(\\sim\\)7 keV, which can be interpreted as either the onset of a broad absorption trough or the blue wing of a relativistic emission line. Overall, this complex feature is significant at >5\\(\\sigma\\), and it is qualitatively reminiscent of a P-Cygni profile. A serendipitous spectrum of lower quality taken by XMM-Newton in 2015 qualitatively confirms the presence of similar Fe-K structures. Although it is not possible to distinguish between the two physical scenarios on sheer statistical grounds with the current data, several considerations lend weight to the possibility that Mrk 1513 is actually hosting a persistent outflow at accretion-disc scales, thus adding to the handful of known AGN in which a wide-angle X-ray wind has been identified so far.

Most of the variability studies of active galactic nuclei (AGNs) are based on ensemble analyses. Nevertheless, it is interesting to provide estimates of the individual variability properties of each AGN, in order to relate them with intrinsic physical quantities. A useful dataset is provided by the Catalina Surveys Data Release 2 (CSDR2), which encompasses almost a decade of photometric measurements of \\(\\sim500\\) million objects repeatedly observed hundreds of times. We aim to investigate the individual optical variability properties of 795 AGNs originally included in the Multi-Epoch XMM Serendipitous AGN Sample 2 (MEXSAS2). Our goals consist in: (i) searching for correlations between variability and AGN physical quantities; (ii) extending our knowledge of the variability features of MEXSAS2 from the X-ray to the optical. We use the structure function (SF) to analyse AGN flux variations. We model the SF as a power-law, \\(\\text{SF}(\\tau)=A\\,(\\tau/\\tau_0)^\\gamma\\), and we compute its variability parameters. We introduce the V-correction as a simple tool to correctly quantify the amount of variability in the rest frame of each source. We find a significant decrease of variability amplitude with increasing bolometric, optical and X-ray luminosity. We obtain the indication of an intrinsically weak positive correlation between variability amplitude and redshift, \\(z\\). Variability amplitude is also positively correlated with \\(\\alpha_\\text{ox}\\). The slope of the SF, \\(\\gamma\\), is weakly correlated with the bolometric luminosity \\(L_\\text{bol}\\) and/or with the black hole mass \\(M_\\text{BH}\\). When comparing optical to X-ray variability properties, we find that X-ray variability amplitude is approximately the same for those AGNs with larger or smaller variability amplitude in the optical. On the contrary, AGNs with steeper SF in the optical do present steeper SF in the X-ray, and vice versa.

Ultra-fast outflows (UFOs) are highly ionized, mildly relativistic winds seen in the X-ray spectra of active galactic nuclei (AGN) and are thought to contribute to AGN feedback and galaxy evolution. We investigate UFO signatures by analyzing a broad collection of published detections. Our final sample comprises 122 robust (> 2\\(\\sigma\\)) UFO detections in 57 AGN, spanning wide ranges in redshift, luminosity, black hole mass, and Eddington ratio. By combining phenomenological and photoionization modeling of the absorption features, we characterize empirical correlations among UFO properties. We find that line width, equivalent width, and outflow velocity are positively correlated, indicating that the broadest and strongest absorption lines trace the fastest winds, although the \\(\\upsilon_\\mathrm{out} - \\sigma\\) trend is comparatively weak. The large inferred velocity dispersions, often exceeding the uncertainty on the centroid velocity, must be included when estimating wind energetics and scaling relations. From the velocity constraints we derive lower limits on the launching radii, finding a minimum distance consistent with the innermost stable circular orbit of a weakly or non-rotating Schwarzschild black hole. We also assess for the first time how UFO properties depend on AGN class: differences between Seyferts and quasars, bridged by narrow-line Seyfert 1 galaxies, appear to be driven mainly by black hole mass and luminosity. The observed co-variation of velocity, width, and equivalent width supports a picture of clumpy, multi-component winds propagating through a thermally unstable multiphase medium within the chaotic cold accretion (CCA) cycle, and is consistent with both magnetically and line-driven acceleration. High-resolution X-ray spectroscopy with missions such as XRISM and NewAthena will be crucial to resolve the structure, kinematics, and physical origin of these flows.

The enigmatic and intriguing phenomenon of the \"soft excess\" observed in the X-ray spectra of luminous quasars continues to be a subject of considerable interest and debate in the field of high-energy astrophysics. This study focuses on the quasar HE 1029-1401 (\\(z=0.086\\), \\(\\log(L_{\\rm{bol}}/[\\rm{erg\\,s^{-1}}])= 46.0 \\pm 0.2\\)), with a particular emphasis on investigating the properties of the hot corona and the physical origin of the soft excess. In this study, we present the results of a joint \\textit{XMM-Newton}/\\textit{NuSTAR} monitoring campaign of this quasar conducted in May 2022. The source exhibits a cold and narrow Fe \\(\\rm{K}\\alpha\\) emission line at 6.4 keV, in addition to the detection of a broad component. Our findings suggest that the soft excess observed in HE 1029-1401 can be adequately explained by Comptonized emission originating from a warm corona. Specifically, fitting the spectra with two \\nthcomp\\, component we found that the warm corona is characterized by a photon index (\\(\\Gamma^{w}\\)) of \\(2.75\\pm0.05\\) and by an electron temperature (\\(kT_{e}^{w}\\)) of \\(0.39^{+0.06}_{-0.04}\\) keV, while the optical depth (\\(\\tau^{w}\\)) is found to be \\(23\\pm3\\). We also test more physical models for the warm corona, corresponding to two scenarios: pure Comptonization and Comptonization plus reflection. Both models provide a good fit to the data, and are in agreement with a radially extended warm corona having a size of a few tens of gravitational radii.

We present the first spatially resolved at \\(20\\) pc scale application of AGN-specific metallicity diagnostics for the nearby Compton-thick Seyfert 2 galaxy Mrk 573 (\\(z = 0.017\\)). We use Hubble Space Telescope narrow-band imaging, MUSE integral-field spectroscopy and apply AGN strong-line metallicity diagnostics based on [O III], [S II], H\\(\\), H\\(\\), and [N II] emission lines. We construct maps of \\(12 + \\)(O/H) for two different metallicity calibrations and two different N/O-O/H scaling relations out to \\(1\\) kpc and down to \\(20\\) pc scales. Our analysis reveals metallicity enhancement in AGN-dominated regions, with oxygen abundances reaching up to few times Solar. The metallicity shows a patchy spatial distribution, varying on \\(100\\) pc scales, appears to trace the high Seyfert/LINER index (SLI) value regions and the VLA 6 cm jet/radio lobe emission. These spatial correspondences and the lack of evidence for star formation in the bicone region suggest that the enrichment originates from metals transported from the nuclear AGN regions by winds, outflows, or jets.