Context. Blue-shifted Fe K absorption lines have been detected in recent years between 7 and 10 keV in the X-ray spectra of several radio-quiet AGNs. The derived blue-shifted velocities of the lines can often reach mildly relativistic values, up to 0.2-0.4c. These findings are important because they suggest the presence of a previously unknown massive and highly ionized absorbing material outflowing from their nuclei, possibly connected with accretion disk winds/outflows. Aims. The scope of the present work is to statistically quantify the parameters and incidence of the blue-shifted Fe K absorption lines through a uniform analysis on a large sample of radio-quiet AGNs. This allows us to assess their global detection significance and to overcome any possible publication bias. Methods. We performed a blind search for narrow absorption features at energies greater than 6.4 keV in a sample of 42 radio-quiet AGNs observed with XMM-Newton. A simple uniform model composed by an absorbed power-law plus Gaussian emission and absorption lines provided a good fit for all the data sets. We derived the absorption lines parameters and calculated their detailed detection significance making use of the classical F-test and extensive Monte Carlo simulations. Results. We detect 36 narrow absorption lines on a total of 101 XMM-Newton EPIC pn observations. The number of absorption lines at rest-frame energies higher than 7 keV is 22. Their global probability to be generated by random fluctuations is very low, less than 3 × 10 −8 , and their detection have been independently confirmed by a spectral analysis of the MOS data, with associated random probability <10 −7 . We identify the lines as Fe XXV and Fe XXVI K-shell resonant absorption. They are systematically blue-shifted, with a velocity distribution ranging from zero up to ∼0.3c, with a peak and mean value at ∼0.1c. We detect variability of the lines on both EWs and blue-shifted velocities among different XMM-Newton observations even on time-scales as short as a few days, possibly suggesting somewhat compact absorbers. Moreover, we find no significant correlation between the cosmological red-shifts of the sources and the lines blue-shifted velocities, ruling out any systematic contamination by local absorption. If we define ultra-fast outflows (UFOs) those highly ionized absorbers with outflow velocities higher than 10 4 km s −1 , then the majority of the lines are consistent with being associated to UFOs and the fraction of objects with detected UFOs in the whole sample is at least ∼35%. This fraction is similar for type 1 and type 2 sources. The global covering fraction of the absorbers is consequently estimated to be in the range C ∼ 0.4−0.6, thereby implying large opening angles. Conclusions. From our systematic X-ray spectral analysis on a large sample of radio-quiet AGNs we have been able to clearly assess the global veracity of the blue-shifted Fe K absorption lines at E > 7 keV and to overcome their publication bias. These lines indicate that UFOs are a rather ...

We present a highly complete and reliable mid-infrared (MIR) colour selection of luminous active galactic nucleus (AGN) candidates using the 3.4, 4.6 and 12 µm bands of the Widefield Infrared Survey Explorer (WISE) survey. The MIR colour wedge was defined using the wide-angle Bright Ultrahard XMM-Newton survey (BUXS), one of the largest complete flux-limited samples of bright (f 4.5-10 keV > 6 × 10 −14 erg s −1 cm −2 ) 'ultrahard' (4.5-10 keV) X-ray-selected AGN to date. The BUXS includes 258 objects detected over a total sky area of 44.43 deg 2 of which 251 are spectroscopically identified and classified, with 145 being type 1 AGN and 106 type 2 AGN. Our technique is designed to select objects with red MIR power-law spectral energy distributions (SEDs) in the three shortest bands of WISE and properly accounts for the errors in the photometry and deviations of the MIR SEDs from a pure power-law. The completeness of the MIR selection is a strong function of luminosity. At L 2-10 keV > 10 44 erg s −1 , where the AGN is expected to dominate the MIR emission, 97.1 +2.2 −4.8 and 76.5 +13.3 −18.4 per cent of the BUXS type 1 and type 2 AGN, respectively, meet the selection. Our technique shows one of the highest reliability and efficiency of detection of the X-rayselected luminous AGN population with WISE amongst those in the literature. In the area covered by BUXS our selection identifies 2755 AGN candidates detected with signal-to-noise ratio ≥5 in the three shorter wavelength bands of WISE with 38.5 per cent having a detection at 2-10 keV X-ray energies. We also analysed the possibility of including the 22 µm WISE band to select AGN candidates, but neither the completeness nor the reliability of the selection improves. This is likely due to both the significantly shallower depth at 22 µm compared with the first three bands of WISE and star formation contributing to the 22 µm emission at the WISE 22 µm sensitivity.

The evolution of galaxies is connected to the growth of supermassive black holes in their centers. During the quasar phase, a huge luminosity is released as matter falls onto the black hole, and radiation-driven winds can transfer most of this energy back to the host galaxy. Over five different epochs, we detected the signatures of a nearly spherical stream of highly ionized gas in the broadband X-ray spectra of the luminous quasar PDS 456. This persistent wind is expelled at relativistic speeds from the inner accretion disk, and its wide aperture suggests an effective coupling with the ambient gas. The outflow's kinetic power larger than 10 46 ergs per second is enough to provide the feedback required by models of black hole and host galaxy co-evolution.Disk winds are theoretically expected as a natural consequence of highly efficient accretion onto supermassive black holes (1), as the energy radiated in this process might easily exceed the local binding energy of the gas. In the past few years, black hole winds with column densities of ~10 23 cm -2 and velocities of ~0.1 times the speed of light (c) have been revealed in a growing number of nearby active galactic nuclei (AGN) through blueshifted X-ray absorption lines (2,3). Outflows of this kind are commonly believed to affect the dynamical and physical properties of the gas in the host galaxy, and, hence, its star formation history (4). However, a complete observational characterization of how this feedback works is still missing. On its own, the detection of narrow, blueshifted features does not convey any information about the opening angle or the ejection site of the wind. This knowledge is critical for measuring the total power carried by the outflow, whose actual influence on galactic scales remains unclear (5).The nearby (z = 0.184) radio-quiet quasar PDS 456 is an established Rosetta stone for studying disk winds (6-8). With a bolometric luminosity L bol ~ 10 47 erg/s, and a mass of the central black hole on the order of 10 9 solar masses (M sun ) (9), it is an exceptionally luminous AGN in the local universe and might be regarded as a counterpart of the accreting supermassive black holes during the peak of quasar activity at high redshift. Since the earliest X-ray observations, PDS 456 has regularly exhibited a deep absorption trough at rest-frame energies above 7 keV (6), which was occasionally resolved with high statistical significance into a pair of absorption lines at ~9.09 and 9.64 keV (7). Because no strong atomic transitions from cosmically abundant elements correspond to these energies, such lines are most likely associated with resonant K-shell absorption from Fe XXV Heα (6.7 keV) and Fe XXVI Lyα (6.97 keV) in a wind with an outflow velocity of ~0.3c.The X-ray Multi-Mirror Mission (XMM)-Newton and Nuclear Spectroscopic Telescope Array (NuSTAR) satellites simultaneously observed PDS 456 on four occasions in 2013, between 27 August and 21 September. A fifth observation was performed several months later, on 26 February 2014 (Table S...

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The existence of ionized X-ray absorbing layers of gas along the line of sight to the nuclei of Seyfert galaxies is a well established observational fact. This material is systematically outflowing and shows a large range in parameters. However, its actual nature and dynamics are still not clear. In order to gain insights into these important issues we performed a literature search for papers reporting the parameters of the soft X-ray warm absorbers (WAs) in 35 type 1 Seyferts and compared their properties to those of the ultra-fast outflows (UFOs) detected in the same sample. The fraction of sources with WAs is >60%, consistent with previous studies. The fraction of sources with UFOs is >34%, >67% of which also show WAs. The large dynamic range obtained when considering all the absorbers together, spanning several orders of magnitude in ionization, column, velocity, and distance allows us, for the first time, to investigate general relations among them. In particular, we find significant correlations indicating that the closer the absorber is to the central black hole, the higher the ionization, column, outflow velocity and consequently the mechanical power. In all the cases, the absorbers continuously populate the whole parameter space, with the WAs and the UFOs lying always at the two ends of the distribution. These evidences strongly suggest that these absorbers, often considered of different types, could actually represent parts of a single large-scale stratified outflow observed at different locations from the black hole. The UFOs are likely launched from the inner accretion disc and the WAs at larger distances, such as the outer disc and/or torus. We argue that the observed parameters and correlations are, to date, consistent with both radiation pressure through Compton scattering and MHD processes contributing to the outflow acceleration, the latter playing a major role. Most of the absorbers, especially the UFOs, show a sufficiently high mechanical power (at least ∼0.5% of the bolometric luminosity) to provide a significant contribution to AGN feedback and thus to the evolution of the host galaxy. In this regard, we find possible evidences for the interaction of the AGN wind with the surrounding environment on large-scales.

We present the results of a new spectroscopic study of Fe K-band absorption in Active Galactic Nuclei (AGN). Using data obtained from the Suzaku public archive we have performed a statistically driven blind search for Fe xxv Heα and/or Fe xxvi Lyα absorption lines in a large sample of 51 type 1.0 − 1.9 AGN. Through extensive Monte Carlo simulations we find that statistically significant absorption is detected at E 6.7 keV in 20/51 sources at the P MC 95% level, which corresponds to ∼ 40% of the total sample. In all cases, individual absorption lines are detected independently and simultaneously amongst the two (or three) available XIS detectors which confirms the robustness of the line detections. The most frequently observed outflow phenomenology consists of two discrete absorption troughs corresponding to Fe xxv Heα and Fe xxvi Lyα at a common velocity shift. From xstar fitting the mean column density and ionisation parameter for the Fe K absorption components are log(N H /cm −2 ) ≈ 23 and log(ξ/erg cm s −1 ) ≈ 4.5, respectively. Measured outflow velocities span a continuous range from < 1, 500 km s −1 up to ∼ 100, 000 km s −1 , with mean and median values of ∼ 0.1 c and ∼ 0.056 c, respectively. The results of this work are consistent with those recently obtained using XMM-Newton and independently provides strong evidence for the existence of very highly-ionised circumnuclear material in a significant fraction of both radio-quiet and radio-loud AGN in the local universe.

We have conducted a multiwavelength survey of 42 radio loud narrow-1ine Seyfert 1 galaxies (RLNLS1s), selected by searching among all the known sources of this type and omitting those with steep radio spectra. We analyse data from radio frequencies to X-rays, and supplement these with information available from online catalogues and the literature in order to cover the full electromagnetic spectrum. This is the largest known multiwavelength survey for this type of source. We detected 90% of the sources in X-rays and found 17% at γ rays. Extreme variability at high energies was also found, down to timescales as short as hours. In some sources, dramatic spectral and flux changes suggest interplay between a relativistic jet and the accretion disk. The estimated masses of the central black holes are in the range ∼ 10 6−8 M ⊙ , lower than those of blazars, while the accretion luminosities span a range from ∼ 0.01 to ∼ 0.49 times the Eddington limit, with an outlier at 0.003, similar to those of quasars. The distribution of the calculated jet power spans a range from ∼ 10 42.6 to ∼ 10 45.6 erg s −1 , generally lower than quasars and BL Lac objects, but partially overlapping with the latter. Once normalised by the mass of the central black holes, the jet power of the three types of active galactic nuclei are consistent with each other, indicating that the jets are similar and the observational differences are due to scaling factors. Despite the observational differences, the central engine of RLNLS1s is apparently quite similar to that of blazars. The historical difficulties in finding radio-loud narrow-line Seyfert 1 galaxies might be due to their low power and to intermittent jet activity.

XMM-Newton observations of 10 ultraluminous infrared galaxies (ULIRGs) from a 200-ks mini-survey programme are reported. The aim is to investigate in hard X-rays a complete ULIRG sample selected from the bright IRAS 60-µm catalogue. All sources are detected in Xrays, five of which for the first time. These observations confirm that ULIRGs are intrinsically faint X-ray sources, their observed X-ray luminosities being typically L 2-10 keV 10 42 -10 43 erg s −1 , whereas their bolometric (mostly infrared) luminosities are L bol > 10 45 erg s −1 . In all sources we find evidence for thermal emission from hot plasma with a rather constant temperature kT 0.7 keV, dominating the X-ray spectra below 1 keV, and probably associated with a nuclear or circumnuclear starburst. This thermal emission appears uncorrelated with the far-infrared luminosity, suggesting that, in addition to the ongoing rate of star formation, other parameters may also affect it. The soft X-ray emission appears to be extended on a scale of ∼30 kpc for Mrk 231 and IRAS 19254−7245, possible evidence of galactic superwinds. In these two sources, IRAS 20551−4250 and 23128−5919, we find evidence for the presence of hidden active galactic nuclei (AGNs), while a minor AGN contribution may be suspected also in IRAS 20100−4156. In particular, we have detected a strong (EW ∼ 2 keV) Fe K line at 6.4 keV in the spectrum of IRAS 19254−7245 and a weaker one in Mrk 231, suggestive of deeply buried AGNs. For the other sources, the X-ray luminosities and spectral shapes are consistent with hot thermal plasma and X-ray binary emissions of mainly starburst origin. We find that the 2-10 keV luminosities in these sources, most probably due to high-mass X-ray binaries, are correlated with L FIR : both luminosities are good indicators of the current global star formation rate in the Galaxy. The composite nature of ULIRGs is then confirmed, with hints for a predominance of the starburst over the AGN phenomenon in these objects even when observed in hard X-rays.