@inproceedings{oai:jaxa.repo.nii.ac.jp:00005265,
 author = {松元, 亮治 and 町田, 真美 and 小田, 寛 and Matsumoto, Ryoji and Machida, Mami and Oda, Hiroshi},
 book = {宇宙航空研究開発機構特別資料, JAXA Special Publication: Astrophysics with All-Sky X-Ray observations: 3rd International MAXI Workshop},
 month = {Feb},
 note = {Astrophysics with All-Sky X-Ray observations: 3rd International MAXI Workshop (RIKEN, 10-12 June 2008), Global three-dimensional magnetohydrodynamic simulations of black hole accretion disks enable us to study the time variabilities of black hole accretion disks without introducing the phenomenological alpha viscosity. Numerical simulations including optically thin radiative cooling revealed that when the disk luminosity exceeds 0.01 L(sub Edd), where L(sub Edd) is the Eddington luminosity, cooling instability taking place in the low/hard state disk creates a magnetically supported, optically thin luminous disk (high/hard state disk) whose X-ray luminosity exceeds 0.1 L(sub Edd) when the accretion rate continues to increase. We found that when the outer region of the disk (r > 20 r(sub s) , where r(sub s) is the Schwarzschild radius) undergoes this transition, an inner torus is formed in r < 10 r(sub s) . The inner torus produces low-frequency quasi-periodic oscillations (QPOs) and high-frequency QPOs whose frequency are 1 - 10 Hz, and ca. 100 Hz, respectively for stellar mass black holes, and 10(exp -6) - 10(exp -5) Hz, and ca. 10(exp -4) Hz, respectively for Seyfert galaxies with black hole mass 10(exp 7) solar mass. When the magnetic energy stored in the disk is released, the disk completes the transition to an optically thick, high/soft state. Monitoring observations by MAXI will detect these transitions in stellar mass black holes and QPOs in AGNs., Physical characteristics: Original contains color illustrations, 資料番号: AA0064306026, レポート番号: JAXA-SP-08-014E},
 pages = {126--131},
 publisher = {宇宙航空研究開発機構, Japan Aerospace Exploration Agency (JAXA)},
 title = {Variability science in accretion disk theory},
 volume = {JAXA-SP-08-014E},
 year = {2009}
}