The luminous narrow line Seyfert galaxy PG1211+143 was the first non-BAL AGN to reveal a powerful ionized wind, based on early observations with ESA's XMM X-ray Observatory. Subsequent observations, mainly with XMM and the Japanese SUZAKU Observatory, found such winds to be a common feature of luminous AGN. Typical outflow velocities of v $\sim 0.1$c and flow momenta $m v \sim L_{\rm Edd} /c$ are consistent with winds being launched by continuum driving from a disc when the local mass accretion rate is super-Eddington. Here we report the launch of a new, ultra-fast outflow component in PG1211+143, near the end of a 5-week XMM observing campaign, and discuss its origin in an ultra-fast {\it inflow} of similar velocity detected some 3 weeks earlier. We find that the inflow lasted for at least 3 days and delivered some 10 Earth mass of fresh material into the innermost region of the source. While this mass by itself is insufficient to cause a complete inner disc restructuring, we show that it is sufficient to disrupt the X-ray emitting corona of the disc. We conclude that it is this coronal re-arrangement of the inner tens gravitational radii in PG1211+143 that subsequently caused the launch of a new wind.

The detection of a high-velocity (similar to 0.3c) inflow of highly ionized matter during an extended XMM-Newton observation of the luminous Seyfert galaxy PG1211+143 in 2014 provided the first direct evidence of a short-lived accretion event, and an explanation for the powerful winds (UFOs) now recognized as a common property of many luminous Seyfert galaxies. Although the ultra-fast inflow observed at a redshift of 0.483 was detected in only one of seven spacecraft orbits, weaker (lower column) but more persistent absorption is seen at a redshift of 0.123 in the high-exposure soft X-ray (RGS) spectra summed over all seven individual spacecraft orbits. Similar stacking of the higher energy (pn camera) spectra reveals underlying absorption at a redshift of 0.148. Interpreted, conventionally, as a Doppler redshift, the RGS observation indicates a line-of-sight inflow velocity v similar to 0.038c and (free-fall) radial location at 1400 R-g, with the higher redshift and ionization in pn camera spectra perhaps detecting that inflow closer to the black hole. A very different explanation would be absorption in matter subject to the strong gravity close to the SMBH, an interpretation supported by the launch of a new UFO in the final spacecraft orbit.

Short-term variability and multiple velocity components in the powerful highly ionized wind of the archetypal UFO PG 1211+143 are indicative of inner disc instabilities or short-lived accretion events. The detection of a high velocity (~ 0.3c) inflow of highly ionized matter, located at 20 R_g, offered the first direct observational support for the latter scenario, where matter approaching at a high inclination to the black hole spin plane may result in warping and tearing of the inner accretion disc, with subsequent inter-ring collisions producing shocks, loss of rotational support and rapid mass infall. Simultaneous soft x-ray spectra reveal a lower velocity (~ 0.1c) inflow of less ionized matter, identified as 'upstream' at 200 R_g, with a line of sight through matter converging on the supermassive black hole. We discuss here why ultrafast ionized winds are relatively common in luminous Seyfert galaxies, while detection of the 0.3c inflow in PG 1211+143 remains a rare example.

Short-term variability and multiple velocity components in the powerful highly ionized wind of the archetypal UFO PG1211+143 are indicative of inner disc instabilities or short-lived accretion events. The recent detection of a high velocity inflow offered the first direct observational support for the latter scenario, where matter approaching at a high inclination to the black hole spin plane may result in warping and tearing of the inner accretion disc, with subsequent inter-ring collisions producing shocks, loss of rotational support and rapid mass infall. Here we identify a variable continuum component in the same data set, well-modelled by a hot thermal Comptonised spectrum that could represent cooling radiation from the shocked gas.

Ken Pounds reviews the history of X-ray astronomy in the UK, more than half a century of fruitful science and instrument development.

Riccardo Giacconi The pioneer of X-ray astronomy and Nobel Prize winner is remembered by Ken Pounds.

Blueshifted absorption lines in the X-ray spectra of an active galactic nucleus (AGN) show that ultrafast outflows with typical velocities upsilon similar to 0.1c are a common feature of these luminous objects. Such powerful AGN winds offer an explanation of the observed M-sigma a relation linking the mass of the supermassive black hole and the velocity dispersion in the galaxy's stellar bulge. An extended XMM Newton study of the luminous Seyfert galaxy PG1211+143 recently revealed a variable multivelocity wind. Here we report the detection of a short-lived, ultrafast inflow during the same observation. Previous reports of inflows used single absorption lines with uncertain identifications, but this new result identifies an array of resonance absorption lines of highly ionized Fe, Ca, Ar, S, and Si, sharing a common redshift when compared with a grid of realistic photoionization spectra. The redshifted absorption arises in a column of highly ionized matter close to the black hole, with a line-of-sight velocity, upsilon similar to 0.3c, inconsistent with the standard picture of a plane circular accretion disc. This may represent the first direct evidence for chaotic accretion in an AGN, where accretion discs are generally misaligned to the black hole spin. For sufficient inclinations, the Lense-Thirring effect can break the discs into discrete rings, which then precess, collide, and shock, causing near free-fall of gas towards the black hole. The observed accretion rate for the reported in fall is comparable to the hard X-ray luminosity in PG1211+143, suggesting that direct in fall may be a significant contributor to inner disc accretion.

We investigate the X-ray time lags of a recent ~630ks XMM-Newton observation of PG 1211+143. We find well-correlated variations across the XMM-Newton EPIC bandpass, with the first detection of a hard lag in this source with a mean time delay of up to ~3ks at the lowest frequencies. We find that the energy-dependence of the low-frequency hard lag scales approximately linearly with log(E) when averaged over all orbits, consistent with the propagating fluctuations model. However, we find that the low-frequency lag behaviour becomes more complex on timescales longer than a single orbit, suggestive of additional modes of variability. We also detect a high-frequency soft lag at ~10^{-4}Hz with the magnitude of the delay peaking at <0.8ks, consistent with previous observations, which we discuss in terms of small-scale reverberation.

The analysis of a series of seven observations of the nearby (z = 0.0809) QSO PG 1211+143, taken with the Reflection Grating Spectrometer (RGS) onboard XMM-Newton in 2014, are presented. The high-resolution soft X-ray spectrum, with a total exposure exceeding 600 ks, shows a series of blueshifted absorption lines from the He and H-like transitions of N, O, and Ne, as well as from L-shell Fe. The strongest absorption lines are all systematically blueshifted by -0.06c, originating in two absorption zones from low-and high-ionization gas. Both zones are variable on timescales of days, with the variations in absorber opacity effectively explained by either column density changes or the absorber ionization responding directly to the continuum flux. We find that the soft X-ray absorbers probably exist in a two-phase wind at a radial distance of similar to 10(17)-10(18) cm from the black hole with the lower-ionization gas as denser clumps embedded within a higher-ionization outflow. The overall mass outflow rate of the soft X-ray wind may be as high as 2M(circle dot) yr(-1), close to the Eddington rate for PG 1211+143 and similar to that previously deduced from the Fe K absorption.

Ken Pounds looks at how X-ray observations continue to transform our understanding of active galactic nuclei.

Fifteen years of XMM-Newton observations have established that ultrafast highly ionized winds (UFOs) are common in radio-quiet active galactic nucleus (AGN). A simple theory of Eddington-limited accretion correctly predicts the typical velocity (∼0.1 c ) and high ionization of such winds, with observed flow energy capable of ejecting star-forming gas. An extended XMM-Newton observation of the archetypal UFO PG 1211+143 recently found a more complex flow pattern, suggesting that intensive XMM-Newton observations offer exciting potential for probing the inner accretion disk structure and super-massive black hole (SMBH) growth.

We report on a timing analysis of a new ~630ks XMM-Newton observation of the quasar, PG 1211+143. We find a well-defined X-ray power spectrum with a well-detected bend at ~7e-5 Hz, consistent with the established bend-timescale--black-hole-mass correlation for luminous, accreting black holes. We find the linear rms-flux relation commonly observed in accreting black hole systems and investigate the energy-dependence of the rms. The fractional rms is roughly constant with energy on short timescales (< 1 day; within observations) whereas there is enhanced soft band variability on long timescales (between observations typically spaced by a few days). Additionally, we also report on the optical--UV variability using the OM on-board XMM-Newton and a ~2-month-long overlapping monitoring programme with Swift. We find that, although there is little UV variability within observations (<1 day), UV variations of a few per cent exist on time-scales of ~days--weeks.

Ken Pounds explains how a report by the Royal Astronomical Society changed UK policy on human space exploration.

An extended XMM-Newton observation of the luminous narrow-line Seyfert galaxy PG1211+143 in 2014 has revealed a more complex high-velocity wind, with components distinguished in velocity, ionization level, and column density. Here we report soft X-ray emission and absorption features from the ionized outflow, finding counterparts of both high-velocity components, v 0.129c and v 0.066c, recently identified in the highly ionized Fe K absorption spectrum. The lower ionization of the comoving soft X-ray absorbers imply a distribution of higher density clouds embedded in the main outflow, while much higher column densities for the same flow component in the hard X-ray spectra suggest differing sightlines to the continuum X-ray source.

ABSTRACT We analyze the broad-band X-ray spectrum (0.3–50 keV) of the luminous Seyfert 1/quasar PG 1211+143—the archetypal source for high-velocity X-ray outflows—using near-simultaneous XMM-Newton and NuSTAR observations. We compare pure relativistic reflection models with a model including the strong imprint of photoionized emission and absorption from a high-velocity wind, finding a spectral fit that extrapolates well over the higher photon energies covered by NuSTAR. Inclusion of the high signal-to-noise ratio XMM-Newton spectrum provides much tighter constraints on the model parameters, with a much harder photon index/lower reflection fraction compared to that from the NuSTAR data alone. We show that pure relativistic reflection models are not able to account for the spectral complexity of PG 1211+143 and that wind absorption models are strongly required to match the data in both the soft X-ray and Fe K spectral regions. In confirming the significance of previously reported ionized absorption features, the new analysis provides a further demonstration of the power of combining the high throughput and resolution of long-look XMM-Newton observations with the unprecedented spectral coverage of NuSTAR.

XMM–Newton is a space science mission developed and operated by the European Space Agency. We acknowledge the excellent work of ESA staff in Madrid in planning and conducting the XMM–Newton observations. The UK Science and Technology Facilities Council funded the post-doctoral research assistantship of AL.

An extended XMM-Newton observation of the luminous narrow line Seyfert galaxy PG 1211+143 in 2014 has revealed a complex high velocity outflow, with components distinguished in velocity, ionization and short-term variability. We report here the detection of previously unseen spectral structure in Fe K absorption, finding a second velocity component of the highly ionized wind, apparently co-moving with a low ionization flow detected in the soft X-ray spectrum. Comparison with the first observation in 2001 finds a similar outflow energy rate. (C) 2016 WILEY-VCH Verlag GmbH&Co. KGaA, Weinheim

An extended XMM-Newton observation of the luminous narrow line Seyfert galaxy PG 1211+143 in 2014 has revealed a more complex highly ionized, high velocity outflow. The detection of previously unresolved spectral structure in Fe K absorption finds a second outflow velocity component of the highly ionized wind, with an outflow velocity of v~0.066+/-0.003c, in addition to a still higher velocity outflow of v~0.129+/-0.002c consistent with that first seen in 2001. We note that chaotic accretion, consisting of many prograde and retrograde events, offers an intriguing explanation of the dual velocity wind. In that context the persisting outflow velocities could relate to physically distinct orientations of the inner accretion flow, with prograde accretion yielding a higher launch velocity than retrograde accretion in a ratio close to that observed.

The National Astronomy Meeting is in its 25th year. Ken Pounds looks back at how it started and how it has evolved.

Active galactic nuclei (AGNs) represent the growth phases of the supermassive black holes in the center of almost every galaxy. Powerful, highly ionized winds, with velocities similar to 0.1-0.2c, are a common feature in X-ray spectra of luminous AGNs, offering a plausible physical origin for the well-known connections between the hole and properties of its host. Observability constraints suggest that the winds must be episodic and detectable only for a few percent of their lifetimes. The most powerful wind feedback, establishing the M-sigma relation, is probably not directly observable at all. The M-sigma relation signals a global change in the nature of AGN feedback. At black hole masses below M-sigma, feedback is confined to the immediate vicinity of the hole. At the M-sigma mass, it becomes much more energetic and widespread and can drive away much of the bulge gas as a fast molecular outflow.