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...

We present a X-ray spectral analysis of a large sample of 25 'bare' active galactic nuclei, sources with little or no complicating intrinsic absorption, observed with Suzaku. Our work focuses on studying the potential contribution from relativistic disc reflection, and examining the implications of this interpretation for the intrinsic spectral complexities frequently displayed by AGN in the X-ray bandpass. During the analysis, we take the unique approach of attempting to simultaneously undertake a systematic analysis of the whole sample, as well as a detailed treatment of each individual source, and find that disc reflection has the required flexibility to successfully reproduce the broadband spectrum observed for all of the sources considered. Where possible, we use the reflected emission to place constraints on the black hole spin for this sample of sources. Our analysis suggests a general preference for rapidly rotating black holes, which if taken at face value is most consistent with the scenario in which SMBH growth is dominated by prolonged, ordered accretion. However, there may be observational biases towards AGN with high spin in the compiled sample, limiting our ability to draw strong conclusions for the general population at this stage. Finally, contrary to popular belief, our analysis also implies that the dichotomy between radio loud/radio quiet AGN is not solely related to black hole spin.

Broad X-ray emission lines from neutral and partially ionized iron observed in active galaxies have been interpreted as fluorescence produced by the reflection of hard X-rays off the inner edge of an accretion disk. In this model, line broadening and distortion result from rapid rotation and relativistic effects near the black hole, the line shape being sensitive to its spin. Alternative models in which the distortions result from absorption by intervening structures provide an equally good description of the data, and there has been no general agreement on which is correct. Recent claims that the black hole (2 × 10(6) solar masses) at the centre of the galaxy NGC 1365 is rotating at close to its maximum possible speed rest on the assumption of relativistic reflection. Here we report X-ray observations of NGC 1365 that reveal the relativistic disk features through broadened Fe-line emission and an associated Compton scattering excess of 10-30 kiloelectronvolts. Using temporal and spectral analyses, we disentangle continuum changes due to time-variable absorption from reflection, which we find arises from a region within 2.5 gravitational radii of the rapidly spinning black hole. Absorption-dominated models that do not include relativistic disk reflection can be ruled out both statistically and on physical grounds.

We present a new catalogue of ∼2400 optically selected quasars with spectroscopic redshifts and X-ray observations from either Chandra or XMM–Newton. The sample can be used to investigate the non-linear relation between the ultraviolet (UV) and X-ray luminosity of quasars as well as to build a Hubble diagram up to a redshift of z ∼ 7.5. We selected sources that are neither reddened by dust in the optical and UV nor obscured by gas in the X-rays, and whose X-ray fluxes are free from flux-limit-related biases. After checking for any possible systematics, we confirm, in agreement with our previous works, that the X-ray to UV relation provides distance estimates matching those from supernovae up to z ∼ 1.5, and its slope shows no redshift evolution up to z ∼ 5. We provide a full description of the methodology for testing cosmological models, further supporting a trend whereby the Hubble diagram of quasars is well reproduced by the standard flat cold dark matter model up to z ∼ 1.5–2, but strong deviations emerge at higher redshifts. Since we have minimised all non-negligible systematic effects and proven the stability of the LX − LUV relation at high redshifts, we conclude that an evolution of the expansion rate of the Universe should be considered as a possible explanation for the observed deviation, rather than some systematic (redshift-dependent) effect associated with high-redshift quasars.