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Testing narrow‐line Seyfert 1 scenarios with photoionization models
Author(s) -
Komossa St.,
Janek M.
Publication year - 1999
Publication title -
astronomische nachrichten
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.394
H-Index - 63
eISSN - 1521-3994
pISSN - 0004-6337
DOI - 10.1002/1521-3994(199908)320:4/5<310::aid-asna310>3.0.co;2-n
Subject(s) - astron , physics , astrophysics , photoionization , planck , astronomy , quantum mechanics , ion , ionization
Narrow Line Seyfert 1 (NLSy1) galaxies have recently received a lot ofattention due to their unusual optical--X-ray properties which are not yet wellunderstood. Photoionization models of the circum-nuclear emission/absorptionregions allow to investigate scenarios to explain the main characteristics ofNLSy1s, i.e., (i) extremely steep X-ray spectra within the ROSAT energy range,(ii) narrow Balmer lines and (iii) weak forbidden lines except for somerelatively strong high-ionization iron lines. Here, we focus on (iii). Inparticular, we study the influence of different EUV - soft-X-ray spectralshapes (a giant soft excess, a steep X-ray powerlaw, presence of a warmabsorber) and NLR cloud properties on the predicted optical emission-lineratios. The calculations were carried out with Ferland's code Cloudy.