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 newly discovered correlation between the wind outflow velocity and the X-ray luminosity in the luminous (L bol ∼ 10 47 erg s −1 ) nearby (z = 0.184) quasar PDS 456. All the contemporary XMM-Newton, NuSTAR and Suzaku observations from 2001-2014 were revisited and we find that the centroid energy of the blueshifted Fe K absorption profile increases with luminosity. This translates into a correlation between the wind outflow velocity and the hard X-ray luminosity (between 7-30 keV) where we find that v w /c ∝ L γ 7−30 where γ = 0.22 ± 0.04. We also show that this is consistent with a wind that is predominately radiatively driven, possibly resulting from the high Eddington ratio of PDS 456.

We present a detailed analysis of a recent, 2013 Suzaku campaign on the nearby (z = 0.184) luminous (L bol ∼ 10 47 erg s −1 ) quasar PDS 456. This consisted of three observations, covering a total duration of ∼ 1 Ms and a net exposure of 455 ks. During these observations, the X-ray flux was unusually low, suppressed by a factor of > 10 in the soft X-ray band when compared to previous observations. We investigated the broadband continuum by constructing a Spectral Energy Distribution (SED), making use of the optical/UV photometry and hard X-ray spectra from the later simultaneous XMM-Newton and NuSTAR campaign in 2014. The high energy part of this low flux SED cannot be accounted for by physically self consistent accretion disc and corona models without attenuation by absorbing gas, which partially covers a substantial fraction of the line of sight towards the X-ray continuum. At least two layers of absorbing gas are required, of column density log(N H,low /cm −2 ) = 22.3 ± 0.1 and log(N H,high /cm −2 ) = 23.2 ± 0.1, with average line of sight covering factors of ∼ 80% (with typical ∼ 5% variations) and 60% (±10 − 15%), respectively. During these observations PDS 456 displays significant short term X-ray spectral variability, on timescales of ∼ 100 ks, which can be accounted for by variable covering of the absorbing gas along the line of sight. The partial covering absorber prefers an outflow velocity of v pc = 0.25 +0.01 −0.05 c at c ? RAS arXiv:1602.04023v1 [astro-ph.HE] 12 Feb 2016 2 Matzeu et al.the > 99.9% confidence level over the case where v pc = 0. This is consistent with the velocity of the highly ionised outflow responsible for the blueshifted iron K absorption profile. We therefore suggest that the partial covering clouds could be the denser, or clumpy part of an inhomogeneous accretion disc wind. Finally estimates are placed upon the size-scale of the X-ray emission region from the source variability. The radial extent of the X-ray emitter is found to be of the order ∼ 15 − 20 R g , although the hard X-ray (> 2 keV) emission may originate from a more compact or patchy corona of hot electrons, which is typically ∼ 6 − 8 R g in size.

Past X-ray observations of the nearby luminous quasar PDS 456 (at z = 0.184) have revealed a wide angle accretion disk wind, with an outflow velocity of ∼−0.25c. Here, we unveil a new, relativistic component of the wind through hard X-ray observations with NuSTAR and XMM-Newton, obtained in 2017 March when the quasar was in a low-flux state. This very fast wind component, with an outflow velocity of −0.46±0.02c, is detected in the iron K band, in addition to the −0.25c wind zone. The relativistic component may arise from the innermost disk wind, launched from close to the black hole at a radius of ∼10 gravitational radii. The opacity of the fast wind also increases during a possible obscuration event lasting for 50 ks. We suggest that the very fast wind may only be apparent during the lowest X-ray flux states of PDS 456, becoming overly ionized as the luminosity increases. Overall, the total wind power may even approach the Eddington value.

We present evidence for the rapid variability of the high velocity iron K-shell absorption in the nearby (z = 0.184) quasar PDS 456. From a recent long Suzaku observation in 2013 (∼ 1 Ms effective duration) we find that the the equivalent width of iron K absorption increases by a factor of ∼ 5 during the observation, increasing from < 105 eV within the first 100 ks of the observation, towards a maximum depth of ∼ 500 eV near the end. The implied outflow velocity of ∼ 0.25 c is consistent with that claimed from earlier (2007, 2011) Suzaku observations. The absorption varies on time-scales as short as ∼ 1 week. We show that this variability can be equally well attributed to either (i) an increase in column density, plausibly associated with a clumpy time-variable outflow, or (ii) the decreasing ionization of a smooth homogeneous outflow which is in photoionization equilibrium with the local photon field. The variability allows a direct measure of absorber location, which is constrained to within r = 200 − 3500 r g of the black hole. Even in the most conservative case the kinetic power of the outflow is 6% of the Eddington luminosity, with a mass outflow rate in excess of ∼ 40% of the Eddington accretion rate. The wind momentum rate is directly equivalent to the Eddington momentum rate which suggests that the flow may have been accelerated by continuum-scattering during an episode of Eddington-limited accretion.