Ultrasoft narrow‐line Seyfert 1 galaxies and X‐ray surveys
作者:
N. Brandt,
T. Boller,
期刊:
Astronomische Nachrichten
(WILEY Available online 1998)
卷期:
Volume 319,
issue 1‐2
页码: 7-10
ISSN:0004-6337
年代: 1998
DOI:10.1002/asna.2123190104
出版商: WILEY‐VCH Verlag
关键词: galaxies: Seyfert;galaxies: active;X‐rays: galaxies
数据来源: WILEY
摘要:
AbstractWe describe how recent X‐ray surveys have led to advances in the understanding of ultrasoft narrow‐line Seyfert 1 galaxies. The number of known ultrasoft narrow‐line Seyfert 1s has increased greatly in recent years due to X‐ray surveys, and it is now possible to obtain high quality 0.1–10 keV spectral and variability measurements for a large number of these galaxies. We generalize some of the correlations between X‐ray properties and optical emission line properties, focusing on how theROSATband spectral slope appears to be directly connected to the Boroson&Green (1992) primary eigenvector. We discuss how ultrasoft narrow‐line Seyfert 1s may well have extremal values of a primary physical parameter, and we describe new projects that should further improve our understanding of these extreme representatives of Sey
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