2 research outputs found
Chemical Abundances in AGN Environment: X-Ray/UV Campaign on the MRK 279 Outflow
We present the first reliable determination of chemical abundances in an AGN
outflow. The abundances are extracted from the deep and simultaneous FUSE and
HST/STIS observations of Mrk 279. This data set is exceptional for its high
signal-to-noise, unblended doublet troughs and little Galactic absorption
contamination. These attributes allow us to solve for the velocity-dependent
covering fraction, and therefore obtain reliable column densities for many
ionic species. For the first time we have enough such column densities to
simultaneously determine the ionization equilibrium and abundances in the flow.
Our analysis uses the full spectral information embedded in these
high-resolution data. Slicing a given trough into many independent outflow
elements yields the extra constraints needed for a physically meaningful
abundances determination. We find that relative to solar the abundances in the
Mrk 279 outflow are (linear scaling): carbon 2.2+/-0.7, nitrogen 3.5+/-1.1 and
oxygen 1.6+/-0.8. Our UV-based photoionization and abundances results are in
good agreement with the independent analysis of the simultaneous Mrk 279 X-ray
spectra. This is the best agreement between the UV and X-ray analyses of the
same outflow to date.Comment: 28 pages, 7 figures, accepted on 29 Nov 2006 for publication in the
ApJ (submission date: 27 Jul 2006