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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…

Outflows from active galactic nuclei (AGN) are often invoked to explain the co-evolution of AGN and their host galaxies, and the scaling relations between the central black hole mass and the bulge velocity dispersion. Nuclear winds are…

High Energy Astrophysical Phenomena · Physics 2018-11-21 A. Luminari , E. Piconcelli , F. Tombesi , L. Zappacosta , F. Fiore , L. Piro , F. Vagnetti

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

Using two-dimensional radiation hydrodynamic simulations, we investigate origin of the ultra fast outflows (UFOs) that are often observed in luminous active galactic nuclei (AGNs). We found that the radiation force due to the spectral lines…

High Energy Astrophysical Phenomena · Physics 2016-01-20 Mariko Nomura , Ken Ohsuga , Hiroyuki R. Takahashi , Keiichi Wada , Tessei Yoshida

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…

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

The fact that luminous X-ray coronae and Ultra-Fast Outflows (UFOs) are both inferred to originate from the innermost regions of active galactic nuclei (AGNs) suggests a deep physical connection between them. However, standard magnetic…

High Energy Astrophysical Phenomena · Physics 2026-03-26 Haichao Xu

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…

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…

IRAS 13224-3809 is one of the most intensively studied narrow-line Seyfert 1 galaxies, with a rich literature reporting diverse and sometimes contrasting interpretations of its complex X-ray spectra and variability. Notably, a fast and…

Over the past decade, a significant amount of effort has been put into investigating the ultraviolet (UV) and optical variability of active galactic nuclei (AGNs). Comprehensive studies of intensive multi-wavelength monitoring and surveys…

High Energy Astrophysical Phenomena · Physics 2025-09-04 M. Papoutsis , I. E. Papadakis , C. Panagiotou , E. Kammoun , M. Dovciak

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

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

UltraFast Outflows (UFO) are observed in some active galactic nuclei (AGN), with blueshifted and highly ionised Fe-K absorption features. AGN typically have a UV bright accretion flow, so UV line driving is an obvious candidate for…

High Energy Astrophysical Phenomena · Physics 2020-11-25 Misaki Mizumoto , Mariko Nomura , Chris Done , Ken Ohsuga , Hirokazu Odaka

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

In radio-loud active galactic nuclei (AGNs), ultra-fast outflows (UFOs) were detected at the inclination angle of $\sim10^{\rm o}$--$70^{\rm o}$ away from jets. Except for the inclination angle of UFOs, the UFOs in radio-loud AGNs have…

High Energy Astrophysical Phenomena · Physics 2021-12-15 Xiao-Hong Yang

Powerful winds at accretion-disk scales have been observed in the past 20 years in many AGN. These are the so-called ultrafast outflows (UFOs). Outflows are intimately related to mass accretion through the conservation of angular momentum,…

Astrophysics of Galaxies · Physics 2024-03-18 Fabrizio Fiore , Massimo Gaspari , Alfredo Luminari , Paolo Tozzi , Lucilla De Arcangelis

We present a comparison of the parameters of accretion disc outflows and the jet of the broad-line radio galaxy 3C 111 on sub-pc scales. We make use of published X-ray observations of ultra-fast outflows (UFOs) and new 43GHz VLBA images to…

High Energy Astrophysical Phenomena · Physics 2015-06-05 F. Tombesi , R. M. Sambruna , A. P. Marscher , S. G. Jorstad , C. S. Reynolds , A. Markowitz

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

Theoretical models of wind-driven feedback from Active Galactic Nuclei (AGN) often identify Ultra-fast outflows (UFOs) as being the main cause for generating galaxy-size outflows, possibly the main actors in establishing the so-called…

High Energy Astrophysical Phenomena · Physics 2020-07-01 E. Bertola , M. Dadina , M. Cappi , C. Vignali , G. Chartas , B. De Marco , G. Lanzuisi , M. Giustini , E. Torresi
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