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SUMMARY:Understanding wind-mode feedback in the X-ray brightest AGN - Anna
  Ogorzalek (Stanford)
DTSTART:20180912T121500Z
DTEND:20180912T124500Z
UID:TALK108514@talks.cam.ac.uk
CONTACT:Dr Giovanni Rosotti
DESCRIPTION:A crucial missing piece in our understanding of AGN feedback i
 s the physics of accretion-driven black hole winds. These fast\, highly io
 nized\, energetic winds\, which can dramatically impact their host galaxie
 s\, imprint their physical states in absorption features seen in the X-ray
  band. In order to robustly map the ionization\, velocity and density stru
 cture of these powerful outflows\, as well as their duty cycles\, high sig
 nal-to-noise\, high spectral resolution data are required\, spanning multi
 ple epochs\; and where such data are available\, their modelling can prese
 nt many challenges.  In this talk I will introduce an improved approach to
  modelling deep X-ray spectra for nearby AGN\, wherein the ionizing spectr
 um and absorption by winds are treated self-consistently within an MCMC an
 alysis. This provides substantial improvements in our ability to explore p
 arameter space and to recover the covariance between the emission and abso
 rption parameters. For the first time\, we are able to perform robust mode
 l selection\, allowing us to establish how many wind components are requir
 ed by the data. By way of example\, we apply our approach to a new\, deep 
 observation of the Seyfert-1 galaxy NGC 4051 (700 ks of Chandra HETG)\, wh
 ere we successfully map multiple absorbing components moving at ~few 1000 
 km/s\, and\, with the use of archival data\, track their temporal evolutio
 n. Future work will extend the analysis to a population study of the physi
 cal structure and duty cycles of disk winds in local AGN\, and serve as a 
 pathfinder for future high spectral resolution X-ray missions\, including 
 XRISM\, Arcus\, and ATHENA.
LOCATION:Sackler Lecture Theatre\, IoA
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