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Related papers: Physical Conditions in Ultra Fast Outflows in AGN

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Among a number of active galactic nuclei (AGNs) that drive ionized outflows in X-rays, a low-redshift (z = 0.184) quasar, PDS 456, is long known to exhibit one of the exemplary ultra-fast outflows (UFOs). However, the physical process of…

High Energy Astrophysical Phenomena · Physics 2018-09-19 Keigo Fukumura , Demosthenes Kazanas , Chris Shrader , Ehud Behar , Francesco Tombesi , Ioannis Contopoulos

Ultra Fast Outflows (UFOs) are powerful, highly ionized winds launched from the innermost regions of Active Galactic Nuclei (AGNs), reaching velocities of 0.03 -- 0.3 c and playing a key role in AGN feedback. We present a photoionization…

High Energy Astrophysical Phenomena · Physics 2025-11-19 Xin Xiang , Jon M. Miller , Ehud Behar , W. N. Brandt , Luigi Gallo , Doyee Byun , Elena Gallo

X-ray evidence for ultra-fast outflows (UFOs) has been recently reported in a number of local AGNs through the detection of blue-shifted Fe XXV/XXVI absorption lines. We present the results of a comprehensive spectral analysis of a large…

High Energy Astrophysical Phenomena · Physics 2012-08-27 F. Tombesi , M. Cappi , R. M. Sambruna , J. N. Reeves , C. S. Reynolds , V. Braito , M. Dadina

X-ray absorption line spectroscopy has recently shown evidence for previously unknown Ultra-fast Outflows (UFOs) in radio-quiet AGNs. In the previous paper of this series we defined UFOs as those absorbers with an outflow velocity higher…

High Energy Astrophysical Phenomena · Physics 2015-05-30 F. Tombesi , M. Cappi , J. N. Reeves , G. G. C. Palumbo , V. Braito , M. Dadina

Ultrafast outflows (UFOs) are the most extreme winds launched by active galactic nuclei (AGN) due to their mildly-relativistic speeds (~0.1-0.3c) and are thought to significantly contribute to galactic evolution via AGN feedback. Their…

The extreme velocities and high ionization states of ultra-fast outflows (UFOs) make them a promising candidate for AGN feedback on the evolution of the host galaxy. However, their exact underlying driving mechanism is not yet fully…

Ultra-fast outflows (UFOs) are highly ionized, mildly relativistic winds seen in the X-ray spectra of active galactic nuclei (AGN) and are thought to contribute to AGN feedback and galaxy evolution. We investigate UFO signatures by…

Relativistically blueshifted absorption features of highly ionised ions, the so-called ultra-fast outflows (UFOs), have been detected in the X-ray spectra of a number of accreting supermassive black holes. If these features truly originate…

High Energy Astrophysical Phenomena · Physics 2020-06-03 P. Kosec , A. Zoghbi , D. J. Walton , C. Pinto , A. C. Fabian , M. L. Parker , C. S. Reynolds

Ultra-fast outflows (UFOs) are mildly relativistic (outflow velocity $v_{out}>0.1c$) nuclear winds detected as blueshifted absorption lines from highly ionized, dense gas in the X-ray spectra of active galactic nuclei. The AGN feedback…

We use MUSE adaptive optics (AO) data in Narrow Field Mode to study the properties of the ionised gas in MR 2251-178 and PG 1126-041, two nearby (z~0.06) bright quasars hosting sub-pc scale Ultra Fast Outflows (UFOs) detected in the X-ray…

The detection of blue-shifted absorption lines likely associated with ionized Iron K-shell transitions in the X-ray spectra of many Active Galactic Nuclei (AGN) suggests the presence of a highly ionized gas outflowing with mildly…

Using the results of a previous X-ray photo-ionization modelling of blue-shifted Fe K absorption lines on a sample of 42 local radio-quiet AGNs observed with XMM-Newton, in this letter we estimate the location and energetics of the…

High Energy Astrophysical Phenomena · Physics 2015-06-03 F. Tombesi , M. Cappi , J. N. Reeves , V. Braito

Ultra-fast outflows (UFOs) are seen in many AGN, giving a possible mode for AGN feedback onto the host galaxy. However, the mechanism(s) for the launch and acceleration of these outflows are currently unknown, with UV line driving…

High Energy Astrophysical Phenomena · Physics 2015-06-23 Kouichi Hagino , Hirokazu Odaka , Chris Done , Poshak Gandhi , Shin Watanabe , Masao Sako , Tadayuki Takahashi

We present a study of X-ray ionization of magnetohydrodynamic (MHD) accretion-disk winds in an effort to constrain the physics underlying the highly-ionized ultra-fast outflows (UFOs) inferred by X-ray absorbers often detected in various…

High Energy Astrophysical Phenomena · Physics 2015-05-27 Keigo Fukumura , Francesco Tombesi , Demosthenes Kazanas , Chris Shrader , Ehud Behar , Ioannis Contopoulos

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…

High Energy Astrophysical Phenomena · Physics 2015-06-22 F. Tombesi , F. Tazaki , R. F. Mushotzky , Y. Ueda , M. Cappi , J. Gofford , J. N. Reeves , M. Guainazzi

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. We detect 36 narrow absorption lines on a total of 101 XMM-Newton EPIC pn observations.…

High Energy Astrophysical Phenomena · Physics 2015-05-19 F. Tombesi , M. Cappi , J. N. Reeves , G. G. C. Palumbo , T. Yaqoob , V. Braito , M. Dadina

During the last decade, strong observational evidence has been accumulated for the existence of massive, high velocity winds/outflows (aka Ultra Fast Outflows, UFOs) in nearby AGNs and in more distant quasars. Here we briefly review some of…

High Energy Astrophysical Phenomena · Physics 2013-01-31 M. Cappi , F. Tombesi , M. Giustini

Ultra Fast Outflows (UFOs) are an established feature in X-ray spectra of AGNs. According to the standard picture, they are launched at accretion disc scales with relativistic velocities, up to 0.3-0.4 c. Their high kinetic power is enough…

High Energy Astrophysical Phenomena · Physics 2021-02-17 A. Luminari , F. Nicastro , M. Elvis , E. Piconcelli , F. Tombesi , L. Zappacosta , F. Fiore

15 years of XMM-Newton observations have established that ultra-fast, highly ionized winds are common in radio-quiet AGN. A simple theory of Eddington-limited accretion correctly predicts the typical velocity (~0.1c) and high ionization of…

Astrophysics of Galaxies · Physics 2017-05-10 Ken Pounds , Andrew Lobban , Chris Nixon

Ultra-fast outflows (UFOs) have been detected in the high-quality X-ray spectra of a number of active galactic nuclei (AGN) with fairly high accretion rates and are thought to significantly contribute to the AGN feedback. After a decade of…

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