Related papers: Probing Broad Absorption Line Quasar Outflows: X-r…
Massive black holes at the centers of galaxies can launch powerful wide-angle winds that, if sustained over time, can unbind the gas from the stellar bulges of galaxies. These winds may be responsible for the observed scaling relation…
We present a brief description of a model for the broad emission line region (BELR) in quasars, which is supported by analysis of CIV and other emission lines in the spectra of high-z SDSS quasars. Specifically we consider a two-component…
The galactocentric distance of quasar absorption outflows are conventionally determined using absorption troughs from excited states, a method hindered by severely saturated or self-blended absorption troughs. We propose a novel method to…
We present a new analysis of a 9-day long XMM-Newton monitoring of the Narrow Line Seyfert 1 galaxy Mrk 766. We show that the strong changes in spectral shape which occurred during this observation can be interpreted as due to Broad Line…
X-ray signatures of outflowing gas have been detected in several accreting black-hole binaries, always in the soft state. A key question raised by these observations is whether these winds might also exist in the hard state. Here, we carry…
A model is presented in which the strongest radio-emitting jet outflows are produced in black hole systems when the accretion is a geometrically thick ($H/R \sim 1$) inflow ({\it e.g.}, ADAF, CDAF) {\em and} if the black hole is rotating.…
We show that black holes supplied with mass at hyper--Eddington rates drive outflows with mildly sub--relativistic velocities. These are $\sim 0.1 - 0.2c$ for Eddington accretion factors $\dot m_{\rm acc} \sim 10 - 100$, and $\sim…
In the last decade, high-resolution X-ray spectroscopy has revolutionized our understanding of the role of accretion disk winds in black hole X-ray binaries. Here I present a brief review of the state of wind studies in black hole X-ray…
Recent X-ray observations show absorbing winds with velocities up to mildly-relativistic values of the order of ~0.1c in a limited sample of 6 broad-line radio galaxies. They are observed as blue-shifted Fe XXV-XXVI K-shell absorption…
Highly-ionized fast accretion-disk winds have been suggested as an explanation for a variety of observed absorption and emission features in the X-ray spectra of Active Galactic Nuclei. Simple estimates have suggested that these flows may…
First indications of the warm/hot intergalactic medium, tracing out the large scale structure of the universe, have been obtained in sensitive Chandra and XMM-Newton high resolution absorption line spectroscopy of bright blazars. High…
Accretion of matter onto black holes is universally associated with strong radiative feedback and powerful outflows. In particular, black hole transients show outflows whose properties are strongly coupled to those of the accretion flow.…
Supermassive black holes underwent periods of exponential growth during which we seem them as quasars in the distant Universe. The summed emission from these quasars generates the cosmic X-ray background, the spectrum of which has been used…
Several AGN and black hole X-ray binaries show a clear very broad iron line which is strong evidence that the black holes are rapidly spinning. Detailed analysis of these objects shows that the emission line is not significantly affected by…
Using long-duration general relativistic magnetohydrodynamic simulations of radiatively inefficient accretion discs, the energy, momentum and mass outflow rates from such systems are estimated. Outflows occur via two fairly distinct modes:…
A variety of investigations have demonstrated commonalities between the Baldwin (1977) Effect, the blueshifting of CIV emission lines (e.g., Gaskell 1982; Richards et al. 2002), and the L_UV-L_X relationship (e.g., Avni & Tananbaum 1982;…
Extremely variable quasars can also show strong changes in broad-line emission strength and are known as changing-look quasars (CLQs). To study the CLQ transition mechanism, we present a pilot sample of CLQs with X-ray observations in both…
Current X-ray surveys have proved to be essential tools in order to identify and study AGNs across cosmic time. However, there is evidence that the most heavily obscured AGNs are largely missing even in the deepest surveys. The search for…
Quasi-periodic eruptions (QPEs) are high-amplitude, soft X-ray bursts recurring every few hours, associated with supermassive black holes. Many interpretations for QPEs were proposed since their recent discovery in 2019, including extreme…
Most Ultraluminous X-ray sources (ULXs) are thought to be powered by super-Eddington accretion onto stellar-mass compact objects. Accretors in this extreme regime are naturally expected to ionise copious amounts of plasma in their vicinity…