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Testing Narrow-line Seyfert 1 scenarios with photoionization models

Stefanie Komossa·Janek Meerschweinchen
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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.

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Stefanie Komossa, Janek Meerschweinchen. 1999-07-27. Testing Narrow-line Seyfert 1 scenarios with photoionization models. https://doi.org/10.1002/1521-3994(199908)320%3A4%2F5%3C310%3A%3Aaid-asna310%3E3.0.co%3B2-n

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