The iron K feature in narrow line Seyfert 1 galaxies: evidence for a P Cygni profile?

• Published in: Monthly notices of the Royal Astronomical Society 2007-01, Vol.374 (1), p.L15-L19
• Main Authors: Done, Chris, Sobolewska, Małgorzata A., Gierliński, Marek, Schurch, Nicholas J.
• Format: Article
• Language: English
• Subjects: accretion; accretion discs; Accretion disks; accretion, accretion discs; Astrophysics; atomic processes; Black holes; galaxies: active; Iron; line: profiles; Stars & galaxies; X-rays: galaxies
• ISSN: 1745-3925; 0035-8711; 1745-3933; 1365-2966
• DOI: 10.1111/j.1745-3933.2006.00255.x

Narrow line Seyfert 1 galaxies are generally accreting at high fractions of the Eddington limit. They can show complex X-ray spectra, with a strong ‘soft excess’ below 2 keV and a sharp drop at ∼7 keV. There is strong evidence linking the soft excess to either reflection or absorption from relativistic, partially ionized material close to the black hole. The reflection models can also simultaneously produce the 7-keV feature from fluorescent iron Kα line emission from the disc. Here we show that absorption can also produce a sharp feature at 7 keV from the P Cygni profile which results from absorption/scattering/emission of He- and H-like iron Kα resonance lines in the wind. We demonstrate this explicitly by fitting the iron feature seen in XMM–Newton data from 1H 0707-495 to a P Cygni profile. The resulting column and ionization required to produce this feature are probably larger than those needed to produce the soft excess. Nonetheless, the absorbing material could still be a single structure with stratified ionization such as that produced by the ionization instability.