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Ultra-fast outflows (UFOs) with mildly relativistic velocities are measured using the X-ray spectra of radio-quiet and -loud active galactic nuclei (AGNs). In general, UFOs are believed to be generated from the accretion disk around a black…

High Energy Astrophysical Phenomena · Physics 2022-08-17 Bei-Chuan Wang , Xiao-Hong Yang , De-Fu Bu , Shu-Su Huang

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

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

Outflows are observed in a variety of astrophysical sources. Remarkably, ultra-fast ($v\geq 0.1c$), outflows in the UV and X-ray bands are often seen in AGNs. Depending on their energy and mass outflow rate, respectively $\dot{E}_{out},…

High Energy Astrophysical Phenomena · Physics 2020-01-15 A. Luminari , F. Tombesi , E. Piconcelli , F. Nicastro , K. Fukumura , D. Kazanas , F. Fiore , L. Zappacosta

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 order to reveal the origin of the ultra-fast outflows (UFOs) that are frequently observed in active galactic nuclei (AGNs), we perform two-dimensional radiation hydrodynamics simulations of the line-driven disk winds, which are…

High Energy Astrophysical Phenomena · Physics 2017-01-25 Mariko Nomura , Ken Ohsuga

Absorption lines with high blue-shifted velocities are frequently found in the ultraviolet (UV) and X-ray spectra of luminous active galactic nuclei (AGNs). This implies that high-velocity winds/outflows are common in AGNs. In order to…

High Energy Astrophysical Phenomena · Physics 2021-06-23 Xiao-Hong Yang , Kamarjan Ablimit , Qi-Xiu Li

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 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

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…

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…

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…

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

Layers of ionized plasma, in the form of winds ejected from the accretion disk of Supermassive Black Holes (SMBHs) are frequently observed in Active Galactic Nuclei (AGNs). Winds with a velocity often exceeding $0.1c$ are called…

High Energy Astrophysical Phenomena · Physics 2023-02-15 M. Marzi , F. Tombesi , A. Luminari , K. Fukumura , D. Kazanas

Accretion disk winds are thought to produce many of the characteristic features seen in the spectra of active galactic nuclei (AGN) and quasi-stellar objects (QSOs). These outflows also represent a natural form of feedback between the…

Astrophysics of Galaxies · Physics 2015-06-18 Nick Higginbottom , Daniel Proga , Christian Knigge , Knox S. Long , James H. Matthews , Stuart A. Sim

The growing evidence for energy-conserving outflows in powerful and luminous AGN supports the idea that high-velocity winds launched from the accretion disc evolve systematically after undergoing a shock with the ambient medium and that…

Astrophysics of Galaxies · Physics 2018-08-06 Anna Lia Longinotti

We show, using global 3D grid-based hydrodynamical simulations, that Ultra Fast Outflows (UFOs) from Active Galactic Nuclei (AGN) result in considerable feedback of energy and momentum into the interstellar medium (ISM) of the host galaxy.…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 A. Y. Wagner , M. Umemura , G. V. Bicknell

We describe the physical mechanisms of launching and acceleration of wind from an active galactic nucleus (AGN) accretion disk. We focus on the radiation line force driven and magnetic driven wind models, which operate on the accretion disk…

High Energy Astrophysical Phenomena · Physics 2024-09-04 De-Fu Bu , Feng Yuan

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

Winds are commonly observed in luminous active galactic nuclei (AGNs). A plausible model of those winds is magnetohydrodynamic (MHD) disc winds. In the case of disc winds from a thin accretion disc, isothermal or adiabatic assumption is…

High Energy Astrophysical Phenomena · Physics 2022-06-22 Weixiao Wang , De-Fu Bu , Feng Yuan
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