| Project/Area Number |
14340061
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Astronomy
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| Research Institution | Osaka University |
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Principal Investigator |
HAYASHIDA Kiyoshi Osaka University, Graduate School of Science, Associate Professor, 大学院・理学研究科, 助教授 (30222227)
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| Co-Investigator(Kenkyū-buntansha) |
INOUE Hajime Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, Professor, 宇宙科学研究本部, 教授 (40092142)
AWAKI Hisamitsu Ehime University, Faculty of Science, Associate Professor, 理学部, 助教授 (30252414)
NEGORO Hitoshi Nihon University, Faculty of Science and Engineering, Lecturer, 理工学部, 専任講師 (30300891)
KATAOKA Jun Tokyo Institute of Technology, Graduate School of Science and Engineering, Assistant Professor, 大学院・理工学研究科, 助手 (90334507)
伊予本 直子 日本学術振興会, 特別研究員
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥9,600,000 (Direct Cost: ¥9,600,000)
Fiscal Year 2004: ¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 2003: ¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 2002: ¥4,000,000 (Direct Cost: ¥4,000,000)
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| Keywords | Black Hole / AGN / X-ray Radiation / Time Variability / Time Series Analysis / Black Hole Mass / X-ray Variability / Jet / クェーサー / 時系列解祈 |
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| Research Abstract |
This research project is aimed to study X-ray variability of Active Galactic Nuclei (AGN) in order to estimate their fundamental properties, such as masses of black holes residing them. We also study physical mechanism to generate radiation from AGNs through X-ray variability and spectra. Our targets range from low luminosity AGNs, Seyfert type 1 and type 2, radio galaxies, and blazers.
1. We proposed to use the power spectra of X-ray variability as a measure of black hole size, namely black hole mass. We originally applied this scheme to bright Seyfert 1 galaxies, but extend it to various types of AGNs, including the lowest luminosity Seyfert 1 galaxy NGC4395, Seyfert 2 galaxies, NGC6300. In these cases, the power spectral shape is similar to that for bright Seyfert 1 galaxies and stellar mass black holes, indicating commmon mechanism is working in these accreting black holes. Black hole mass of NGC4395 is estimated to be tens of thousand Solar mass, which is intermediate between stellar mass black holes and super massive black holes and important for models for black hole evolution.
2.Variabilities in X-ray intensity and spectra were studied in detail in several sources, including Ark564, MCG-6-30-15, and many blazers. Iron emission line is usually interpreted as a fluorescent line from the vicinity of a black hole, but alternative models proposed for MCG-6-30-15. X-ray and other wave length data on variabilities of blazers indicate physical mechanism occurred in jet from these sources. We show internal shock is important to explain the spectral evolution of some of the flares in blazers.
3.We thick we can use X-ray variability as a tool to estimate black hole size, but the origin and physical mechanism that makes the variability is still unclear. That will be the next step for our study.
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