An ultrasoft X-ray source (RX 215319-1514) and discovery of a narrow-line Seyfert 1 galaxy
نویسندگان
چکیده
منابع مشابه
An Ultra-soft X-ray Source (rx 215319-1514) and Discovery of a Narrow Line Seyfert 1 Galaxy
We present results on the identification of the optical counterpart of an ultra-soft X-ray source discovered with ROSAT . Two optical candidates – a galaxy and a star, are found within the error circle of the X-ray source position. Optical spectroscopy of the two candidates reveals that a) the galaxy is a narrow-line Seyfert type 1 galaxy, and b) the star is a late A-type or an early F-type. Th...
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We 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 c...
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We have discovered a Narrow-Line Seyfert 1 (NLS1) galaxy and identified it with an ultrasoft X-ray source (RX 215319-1514) detected with ROSAT . We present its X-ray and optical spectral characteristics. Its redshift is found to be 0.0778±0.0002. Its optical spectrum shows fairly strong Fe II emission lines, and its X-ray spectrum has an extremely steep power-law index of Γ ≥4, making it an ext...
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We show that the large variations in the X-ray flux of the extreme narrow-line Seyfert 1 galaxy IRAS 13224 3809, measured during a 10 day ASCA observation, have a two-parameter lognormal distribution of multiplicative standard deviation and that the amplitude of variability at any given moment is proportional to the flux j p 2.7 mult level. We find similar behavior in earlier ROSAT soft X-ray m...
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A model for the inner regions of accretion flows is presented where, due to disc instabilities, cold and dense material is clumped into deep sheets or rings. Surrounding these density enhancements is hot, tenuous gas where coronal dissipation processes occur. We expect this situation to be most relevant when the accretion rate is close to Eddington and the disc is radiation-pressure dominated, ...
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ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 2000
ISSN: 0035-8711,1365-2966
DOI: 10.1046/j.1365-8711.2000.03136.x