Outflows vs. Clouds in AGN Intrinsic Absorbers

Preprint English OPEN
Arav, Nahum (2003)
  • Subject: Astrophysics
    arxiv: Astrophysics::Galaxy Astrophysics | Astrophysics::Cosmology and Extragalactic Astrophysics | Astrophysics::High Energy Astrophysical Phenomena

We discuss the crucial role of a dynamical picture in the analysis of AGN intrinsic absorbers data. High quality FUSE data of Mrk 279 are used to demonstrate that the line of sight covering fraction is a strong function of velocity. In Mrk 279, as well as in most cases where the data is of high enough quality, the shape of the absorption troughs is mainly determined by the velocity-dependent covering fraction. We argue that the traditional ``cloud'' picture of AGN outflows is hard pressed to account for the velocity-dependent covering fraction, as well as for the highly super-thermal width of the troughs and the detached trough phenomenon. A disk outflow picture naturally explains these features and furthermore, is using the simplest reservoir for the outflowing material: The accretion disk around the black hole. Accounting for velocity dependent covering can drastically increase the inferred ionic column density of the analyzed trough, an increase which is amplified in the total column density and ionization parameter solution for the AGN outflow trough.
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