Kyoto University · Physics and Astronomy
Professor Shoji Ogawa's research lab specializes in high-energy astrophysics, focusing on active galactic nuclei (AGNs) and the physics of X-ray emission and absorption in extreme environments. The lab employs advanced X-ray spectral modeling using clumpy torus models such as XCLUMPY and CLUMPY to study the structure and geometry of dusty tori around supermassive black holes. They also investigate ionized outflows, warm absorbers, and relativistic reflection in AGNs using data from X-ray observatories like XRISM, NuSTAR, XMM-Newton, and Suzaku, often combining X-ray and infrared data for multi-wavelength analysis. Their work contributes to understanding the connection between accretion, feedback, and the evolution of galaxies and black holes.
Figures are computed from collected data and may differ slightly.
Abstract We present the results of a systematic, broadband X-ray spectral analysis of nearby active galactic nuclei (AGNs) with the X-ray clumpy torus model (XCLUMPY). By adding 16 AGNs newly analyzed in this paper, we study a total of 28 AGNs, including unabsorbed and absorbed AGNs taken from Ichikawa et al. and García-Bernete et al. This is the largest sample whose X-ray and infrared spectra are analyzed by the clumpy torus models XCLUMPY and CLUMPY, respectively. The relation between the Eddi
Abstract We apply a new X-ray clumpy torus model, XCLUMPY, in which the clump distribution is assumed to be the same as that in the infrared clumpy torus model (CLUMPY) by Nenkova et al., to the broadband X-ray spectra of type-1 active galactic nuclei (AGNs) for the first time. We analyze the archival data of IC 4329A and NGC 7469 observed with NuSTAR / Suzaku and NuSTAR / XMM-Newton , respectively, whose infrared spectra were studied with CLUMPY by Ichikawa et al. and optical extinctions ( A V
Abstract To investigate the origins of the warm absorbers in active galactic nuclei (AGNs), we study the ionization-state structure of the radiation-driven fountain model in a low-mass AGN and calculate the predicted X-ray spectra utilizing the spectral synthesis code Cloudy . The spectra show many absorption and emission line features originating in the outflowing ionized gas. The O viii 0.654 keV lines are produced mainly in the polar region much closer to the supermassive black hole than the
Abstract We present the first high-resolution X-ray spectrum of NGC 7213 obtained with XRISM/Resolve, supported by simultaneous XMM-Newton, NuSTAR, and SOAR optical data. The XRISM spectrum resolves the neutral Fe K α into two components: a narrow core ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi mathvariant="normal">FWHM</mml:mi> <mml:mo>=</mml:mo> <mml:mn>65</mml:mn> <mml:msubsup> <mml:mrow> <mml:mn>0</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <
The Kyoto University Digital Library makes images of the rare materials that it holds available to general public. While most of the pages consist of scanned images alone, some are accompanied by corresponding encoded text data. This report summarizes the principal parts of the procedures for producing image data. Demand for a well-designed interface grows as the amount of available digital data expands, as the Internet environment develops with easier access to digital contents and as high-qual
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