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Title: Revealing the location and structure of the accretion disk wind in PDS 456

We present evidence for the rapid variability of the high-velocity iron K-shell absorption in the nearby (z = 0.184) quasar PDS 456. From a recent long Suzaku observation in 2013 (∼1 Ms effective duration), we find that the equivalent width of iron K absorption increases by a factor of ∼5 during the observation, increasing from <105 eV within the first 100 ks of the observation, toward a maximum depth of ∼500 eV near the end. The implied outflow velocity of ∼0.25 c is consistent with that claimed from earlier (2007, 2011) Suzaku observations. The absorption varies on timescales as short as ∼1 week. We show that this variability can be equally well attributed to either (1) an increase in column density, plausibly associated with a clumpy time-variable outflow, or (2) the decreasing ionization of a smooth homogeneous outflow which is in photo-ionization equilibrium with the local photon field. The variability allows a direct measure of absorber location, which is constrained to within r = 200-3500 r {sub g} of the black hole. Even in the most conservative case, the kinetic power of the outflow is ≳ 6% of the Eddington luminosity, with a mass outflow rate in excess of ∼40%more » of the Eddington accretion rate. The wind momentum rate is directly equivalent to the Eddington momentum rate which suggests that the flow may have been accelerated by continuum scattering during an episode of Eddington-limited accretion.« less
Authors:
; ; ; ;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6]
  1. Astrophysics Group, School of Physical and Geographical Sciences, Keele University, Keele, Staffordshire, ST5 5BG (United Kingdom)
  2. INAF-Osservatorio Astronomico di Brera, Via Bianchi 46 I-23807 Merate (Italy)
  3. Department of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH (United Kingdom)
  4. Department of Physics, University of Durham, South Road, Durham, DH1 3LE (United Kingdom)
  5. Center for Space Science and Technology, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250 (United States)
  6. Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford, OX1 3RH (United Kingdom)
Publication Date:
OSTI Identifier:
22351483
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 784; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCRETION DISKS; BLACK HOLES; DENSITY; EQUILIBRIUM; EV RANGE; IRON; K ABSORPTION; K SHELL; LUMINOSITY; MASS; PHOTONS; QUASARS; SCATTERING; X-RAY GALAXIES