Issue |
A&A
Volume 428, Number 1, December II 2004
|
|
---|---|---|
Page(s) | 57 - 66 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361:20041434 | |
Published online | 23 November 2004 |
X-ray/UV campaign on the Mrk 279 outflow: Density diagnostics in Active Galactic Nuclei using O v K-shell absorption lines
1
SRON National Institute for Space Research Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands e-mail: J.Kaastra@sron.nl
2
Astronomical Institute “Anton Pannekoek”, Kruislaan 403, 1098 SJ Amsterdam, The Netherlands
3
CASA, University of Colorado, 389 UCB, Boulder, CO 80309-0389, USA
4
Department of Physics, Technion-Israel Institute of Technology, Haifa 32000, Israel
5
Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
6
KIPAC/SLAC, 2575 Sand Hill Road M/S 29, Menlo Park, Ca 94025, USA
Received:
8
June
2004
Accepted:
12
August
2004
One of the main problems in modeling the ionised outflows in Active Galactic
Nuclei is the unknown distance of the outflowing wind to the central source.
Only if the density is known this distance can be determined through the
ionisation parameter. Here we study density diagnostics based upon
transitions.
is known to have metastable levels that are density
dependent. We study the population of those levels under photoionisation
equilibrium conditions and determine for which parameter range they can have a
significant population. We find that resonance line trapping plays an important
role in reducing the critical densities above which the metastable population
becomes important. We investigate the K-shell absorption lines from these
metastable levels. Provided that there is a sufficient population of the
metastable levels, the corresponding K-shell absorption lines are detectable
and are well separated from the main absorption line originating from the
ground state. We then present the Chandra LETGS spectrum of the Seyfert 1
galaxy Mrk 279 that may show for the first time the presence of these
metastable level absorption lines. A firm identification is not yet possible
due to both uncertainties in the observed wavelength of the strongest line as
well as uncertainties in the predicted wavelength. If the line is indeed due to
absorption from
, then we deduce a distance to the central source of
one light week to a few light months, depending upon the importance of
additional heating processes.
Key words: galaxies: individual: Mrk 279 / galaxies: Seyfert / galaxies: quasars: absorption lines / X-rays: galaxies
© ESO, 2004
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.