Physical Conditions in Ultra Fast Outflows in AGN

Abstract

XMM-Newton and Suzaku spectra of AGN have revealed highly ionized gas, in the form of absorption lines from H-like and He-like Fe. Some of these absorbers, "Ultra Fast Outflows (UFOs)", have radial velocities of up to 0.25c. We have undertaken a detailed photo-ionization study of high-ionization Fe absorbers, both UFOs and non-UFOs, in a sample of AGN observed by XMM-Newton. We find that the heating and cooling processes in UFOs are Compton-dominated, unlike the non-UFOs. Both types are characterized by Force Multipliers on the order of unity, which suggests that they cannot be radiatively accelerated in sub-Eddington AGN, unless they were much less ionized at their point of origin. However, such highly ionized gas can be accelerated via a Magneto-Hydrodynamic (MHD) wind. We explore this possibility by applying a cold MHD flow model to the UFO in the well-studied Seyfert galaxy, NGC 4151. We find that the UFO can be accelerated along magnetic streamlines anchored in the accretion disk. In the process, we have been able to constrain the magnetic field strength and the magnetic pressure in the UFO and have determined that the system is not in magnetic/gravitational equipartition.Open questions include the variability of the UFOs and the apparent lack of non-UFOs in UFO sources.

18 pages, 9 figures. Accepted for publication in the Astrophysical Journal

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• Physical Conditions in the X-ray Emission-line Gas in NGC 1068
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Cited by in corpus (19)

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• Searching for Ultra-fast Outflows in AGN using Variability Spectra
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• The large-scale magnetic field of a thin accretion disk with outflows
• Relativistic components of the Ultra-Fast Outflow in the Quasar PDS 456 from Chandra/HETGS, NuSTAR and XMM-Newton observations
• Location and energetics of the ultra-fast outflow in PG 1448+273
• Mass Outflow of the X-ray Emission Line Gas in NGC 4151
• The flaring X-ray corona in the quasar PDS 456
• Tell-Tale Spectral Signatures of MHD-driven Ultra-Fast Outflows in AGNs
• Modeling Magnetic Disk-Wind State Transitions in Black Hole X-ray Binaries
• Investigating the Narrow Line Region Dynamics in Nearby Active Galaxies
• Supermassive Black Hole Winds in X-rays -- SUBWAYS. III. A population study on ultra-fast outflows
• XRISM Spectroscopy of Accretion-Driven Wind Feedback in NGC 4151
• The large-scale magnetic field advected in the corona of a thin accretion disk
• Ultra-high-energy cosmic rays from ultra-fast outflows of active galactic nuclei
• The dynamical structure of the outflows driven by a large-scale magnetic field
• Constraining X-ray Coronal Size with Transverse Motion of AGN Ultra-Fast Outflows
• Feedback from intermediate mass black holes on dwarf galaxy morphology at z=2
• Unveiling the dynamics of the ultra-fast outflow in IRAS 13224-3809 with X-ray spectroscopy