Open AccessFe xxv and Fe xxvi lines from low‐velocity, photoionized gas in the X‐ray spectra of active galactic nuclei
Author(s) -
Bianchi Stefano,
Matt Giorgio,
Nicastro Fabrizio,
Porquet Delphine,
Dubau Jacques
Publication year - 2005
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2005.08661.x
Subject(s) - physics , active galactic nucleus , compton scattering , spectral line , ionization , astrophysics , galaxy , emission spectrum , line (geometry) , absorption (acoustics) , absorption spectroscopy , plasma , equivalent width , atomic physics , scattering , ion , astronomy , nuclear physics , optics , geometry , mathematics , quantum mechanics
We have calculated the equivalent widths of the absorption lines produced by Fe xxv and Fe xxvi in a Compton‐thin, low‐velocity photoionized material illuminated by the nuclear continuum in active galactic nuclei. The results, plotted against the ionization parameter and the column density of the gas, are a complement to those presented by Bianchi & Matt for the emission lines from the same ionic species. As an extension to the work by Bianchi & Matt, we also present a qualitative discussion on the different contributions to the He‐like iron emission line complex in the regimes where recombination or resonant scattering dominates, providing a useful diagnostic tool to measure the column density of the gas. Future high‐resolution missions (e.g. Astro‐E2 ) will allow us to fully take advantage of these plasma diagnostics. In the meantime, we compare our results with an up‐to‐date list of Compton‐thick and unobscured (at least at the iron line energy) Seyfert galaxies with emission and/or absorption lines from H‐ and He‐like iron observed with Chandra and XMM–Newton .