120 citations · 570 across the 16 of their papers we have counts for
16 papers
Semi-Analytical Model for Wind-Fed Black Hole High-Mass X-ray Binaries -- State Transition Triggered by Magnetic Fields from the Companion Star --
Kentaro Yaji, Shinya Yamada, Kuniaki Masai
We propose a mechanism of state transition in wind-fed black hole binaries (high-mass X-ray binaries) such as Cyg X-1 and LMC X-1. Modeling a line-driven stellar wind from the comp…
Multi-Year X-ray Variations of Iron-K and Continuum Emissions in the Young Supernova Remnant Cassiopeia A
Toshiki Sato, Yoshitomo Maeda, Aya Bamba +9
We found simultaneous decrease of Fe-K line and 4.2-6 keV continuum of Cassiopeia A with the monitoring data taken by Chandra in 2000-2013. The flux change rates in the whole remna…
Discovery of Enhanced Radiative Recombination Continua of He-like Iron and Calcium from IC 443 and Its Implications
Takao Ohnishi, Hiroyuki Uchida, Takeshi Go Tsuru +3
We present deep observations of the Galactic supernova remnant IC 443 with the {\it Suzaku X-ray satellite}. We find prominent K-shell lines from iron and nickel, together with a t…
Non-Thermal Radio and Gamma-Ray Emission from a Supernova Remnant by the Blast Wave Breaking Out of the Circumstellar Matter
Takafumi Shimizu, Kuniaki Masai, Katsuji Koyama
We calculate synchrotron radio emission and gamma-ray emission due to bremsstrahlung, inverse-Compton scattering and -decay from the remnant of supernova which exploded in th…
Density Profile of a Cool Core of Galaxy Clusters
Naomi Ota, Kiyokazu Onzuka, Kuniaki Masai
The density profile of a cool core of intracluster gas is investigated for a cluster of galaxies that is initially in the virial equilibrium state, and then undergoes radiative coo…
Evolution of Supernova Remnants Expanding out of the Dense Circumstellar Matter into the Rarefied Interstellar Medium
Takafumi Shimizu, Kuniaki Masai, Katsuji Koyama
We carry out 3D-hydrodynamical calculations for the interaction of expanding supernova ejecta with the dense circumstellar matter (CSM) and the rarefied interstellar medium (ISM) o…
X-Ray Spectrum of a Peculiar Supernova Remnant G359.1-0.5
Takao Ohnishi, Katsuji Koyama, Takeshi Go Tsuru +3
We present the Suzaku results of a supernova remnant (SNR), G359.1-0.5 in the direction of the Galactic center region. From the SNR, we find prominent K-shell lines of highly ioniz…
Suzaku Discovery of the Strong Radiative Recombination Continuum of Iron from the Supernova Remnant W49B
Midori Ozawa, Katsuji Koyama, Hiroya Yamaguchi +2
We present a hard X-ray spectrum of unprecedented quality of the Galactic supernova remnant W49B obtained with the Suzaku satellite. The spectrum exhibits an unusual structure cons…
Discovery of Strong Radiative Recombination Continua from The Supernova Remnant IC 443 with Suzaku
Hiroya Yamaguchi, Midori Ozawa, Katsuji Koyama +4
We present the Suzaku spectroscopic study of the Galactic middle-aged supernova remnant (SNR) IC 443. The X-ray spectrum in the 1.75-6.0 keV band is described by an optically-thin…
Evidence for Resonance Line Scattering in the Suzaku X-ray Spectrum of the Cygnus Loop
Emi Miyata, Kuniaki Masai, John P. Hughes
We present an analysis of the Suzaku observation of the northeastern rim of the Cygnus Loop supernova remnant. The high detection efficiency together with the high spectral resolut…
Core Structure of Intracluster Gas: Effects of Radiative Cooling on Core Sizes
Takuya Akahori, Kuniaki Masai
We investigate the core structure of radiatively cooling intracluster gas, using a hydrodynamics code. We calculate evolution of model clusters of the initial core radii 160--300 k…
L_X-T Relation and Related Properties of Galaxy Clusters
Naomi Ota, Tetsu Kitayama, Kuniaki Masai +1
An observational approach is presented to constrain the global structure and evolution of the intracluster medium based on the ROSAT and ASCA distant cluster sample. From statistic…
Core Structure of Intracluster Gas: Isothermal Hydrostatic Equilibrium
Takuya Akahori, Kuniaki Masai
We investigate core structures of X-ray emitting intracluster gas based on the so-called beta-model, which is an isothermal hydrostatic model often used in observational studies. W…
Quasi-hydrostatic intracluster gas under radiative cooling
Kuniaki Masai, Tetsu Kitayama
Quasi-hydrostatic cooling of the intracluster gas is studied. In the quasi-hydrostatic model, work done by gravity on the inflow gas with dP \neq 0, where P is the gas pressure, is…
ASCA Observations of the Supernova Remnant IC 443: Thermal Structure and Detection of Overionized Plasma
Masahiro Kawasaki, Masanobu Ozaki, Fumiaki Nagase +3
We present the results of X-ray spatial and spectral studies of the ``mixed-morphology'' supernova remnant IC 443 using ASCA. IC 443 has a center-filled image in X-ray band, contra…
Non-Equilibrium Ionization States of GRB Environments
D. Yonetoku, T. Murakami, K. Masai +3
Iron spectral features are thought to be the best tracer of a progenitor of gamma-ray bursts (GRBs). The detections of spectral features such as an iron line and/or a Radiative Rec…