2013 Fiscal Year Final Research Report
X-ray spectral and polarimetric study on rapid variability of black holes
| Project/Area Number |
24740129
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Astronomy
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| Research Institution | Institute of Physical and Chemical Research |
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Principal Investigator |
SHINYA Yamada 独立行政法人理化学研究所, 仁科加速器研究センター, 基礎科学特別研究員 (40612073)
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| Project Period (FY) |
2012-04-01 – 2014-03-31
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| Keywords | ブラックホール / 宇宙 / X線 |
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| Research Abstract |
Our aim is to understand general relativistic accretion flow around a black hole by observing X-ray binaries of a black hole. We have analyzed a famous black hole binary, Cygnus X-1, using Suzaku X-ray observatory in the low/hard were conducted in a model-independent manner. Variations on short (seconds) and long (days to months) time scales require a constant component localized below 2 keV, a broad soft one dominating in the 2-10 keV range, and a hard one mostly seen in 10-300 keV range. These are respectively interpreted as emission from the truncated cool disk, a soft Compton component, and a hard Compton component in view of the truncated disk/hot inner flow picture. Long-term spectral evolution can be produced by the constant disk increasing in temperature and luminosity as the truncation radius decreases. Furthermore, we found highly ionized Fe-K absorption lines, which can be a probe of accretion geometry.
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