Testing Narrow-line Seyfert 1 scenarios with photoionization models
arXiv:astro-ph/9907373 · doi:10.1002/1521-3994(199908)320:4/5<310::AID-ASNA310>3.0.CO;2-N
Abstract
Narrow Line Seyfert 1 (NLSy1) galaxies have recently received a lot of attention due to their unusual optical--X-ray properties which are not yet well understood. Photoionization models of the circum-nuclear emission/absorption regions allow to investigate scenarios to explain the main characteristics of NLSy1s, i.e., (i) extremely steep X-ray spectra within the ROSAT energy range, (ii) narrow Balmer lines and (iii) weak forbidden lines except for some relatively strong high-ionization iron lines. Here, we focus on (iii). In particular, we study the influence of different EUV - soft-X-ray spectral shapes (a giant soft excess, a steep X-ray powerlaw, presence of a warm absorber) and NLR cloud properties on the predicted optical emission-line ratios. The calculations were carried out with Ferland's code Cloudy.
Contribution to "Heating and Acceleration in the Universe" (Tokyo, March 17-19, 1999), H.Inoue, T.Ohashi, T.Takahashi (eds); Astronomische Nachrichten 320, 1999, in press. Preprint and related papers also available at http://www.xray.mpe.mpg.de/~skomossa/