603 citations · 1.5k across the 33 of their papers we have counts for
33 papers
A Possible Origin of kHZ QPOs in Low-Mass X-ray Binaries
Shoji Kato, Mami Machida
A possible origin of kHz QPOs in low-mass X-ray binaries is proposed. Recent numerical MHD simulations of accretion disks with turbulent magnetic fields of MRI definitely show the…
Self-Trapping of G-Mode Oscillations in Relativistic Thin Disks, Revisited II: Revision of Boundary Condition
Shoji Kato
In a previous paper (Kato 2017a) we have examined how the self-trapping of g-mode oscillations in geometrically thin relativistic disks is affected by the presence of uniform verti…
Self-Trapping of G-Mode Oscillations in Relativistic Thin Disks, Revisited
Shoji Kato
We examine by a perturbation method how the self-trapping of g-mode oscillations in geometrically thin relativistic disks is affected by uniform vertical magnetic fields. Disks whi…
Simultaneous Resonant Excitation of Low-frequency Eccentric Wave and Tilt Wave on Tidally Deformed Disks
Shoji Kato
Simultaneous excitation of low-frequency eccentric precessing mode (one-armed p-mode) and tilt mode on tidally deformed disks is considered. If the orbit of the secondary star is e…
Resonant Excitation of Disk Oscillations in Deformed Disks VII: Stability Criterion in MHD Systems
Shoji Kato
In a disk with an oscillatory deformation from an axisymmetric state with frequency and azimuthal wavenumber , a set of two normal mode oscillations with fre…
Resonant Excitation of Tilt Mode in Tidally Deformed Disks
Shoji Kato
In a previous paper (Kato 2013b), we have shown that in deformed disks a pair of trapped oscillation modes can be resonantly excited through couplings with disk deformation. In thi…
Resonant Excitation of Disk Oscillations in Deformed Disks VI: Stability Criterion Revisited
Shoji Kato
We re-examine excitation of a set of disk oscillations in a deformed disk by a resonant process. We assume that the disk is deformed from an axisymmetric steady state by an oscilla…
Tidal Instability and Superhump by a Wave-Wave Resonant Model
Shoji Kato
On a disk deformed to a non-axisymmetric form, a set of oscillations can be excited by their resonant interaction through the disk deformation (Kato et al. 2011). This resonant ins…
A Resonantly-Excited Disk-Oscillation Model of High-Frequency QPOs of Microquasars
Shoji Kato
A possible model of twin high-frequency QPOs (HF QPOs) of microquasars is examined. The disk is assumed to have global magnetic fields and to be deformed with a two-armed pattern.…
An Attempt to Describe Frequency-Correlations among kHz QPOs and HBOs by Two-Armed Vertical p-mode Oscillations: Case of No Magnetic Field
Shoji kato
Trapping of two-armed () vertical p-mode oscillations in relativistic disks are examined. The disks are assumed to be isothermal in the vertical direction, but are truncated a…
An Attempt to Describe Frequency Correlations among kHz QPOs and HBOs by Two-Armed Nearly Vertical Oscillations
Shoji Kato
We examine whether the two-armed () vertical p-mode oscillations trapped in the innermost region of magnetized accretion disks with finite disk thickness can describe kHz QPOs…
Trapped, Two-Armed, Nearly Vertical Oscillations in Disks with Toroidal Magnetic Fields II: Effects of Finite Thickness
Shoji Kato
We examine radial trapping of two-armed () vertical p-mode oscillations in geometrically thin relativistic disks which are vertically isothermal but terminated at a certain he…
Correlated Frequency-Changes of Trapped Vertical p-mode Oscillations and kHz QPOs
Shoji Kato
We have examined the frequencies of trapped two-armed () nearly vertical oscillations (vertical p-mode) in vertically isothermal disks with toroidal magnetic fields. The magne…
Resonant Excitation of Disk Oscillations in Deformed Disks V: Effects of Dissipative Process
Shoji Kato
It is suggested that a set of positive- and negative-energy oscillations can be resonantly excited in the inner region of deformed (warped or eccentric) relativistic disks. In this…
Resonant Excitation of Disk Oscillations in Deformed Disks IV: A New Formulation Studying Stability
Shoji Kato, Atsuo T. Okazaki, Finny Oktariani
The possibility has been suggested that high-frequency quasi-periodic oscillations observed in low-mass X-ray binaries are resonantly excited disk oscillations in deformed (warped…
Trapped, Two-Armed, Nearly Vertical Oscillations in Disks with Toroidal Magnetic Fields
Shoji Kato
We have examined trapping of two-armed () nearly vertical oscillations (vertical p-mode) in vertically isothermal ( const.) relativistic disks with toroidal magnet…
Excitation of Trapped g-Mode Oscillations in Warped Disks around Black Holes
Finny Oktariani, Atsuo T. Okazaki, Shoji Kato
In order to study the origin of high-frequency quasi-periodic oscillations observed in X-ray binaries, Kato (2004) suggested a resonant excitation mechanism of disk oscillations in…
Trapped, Two-Armed, Nearly Vertical Oscillations in Polytropic Disks
Shoji Kato
We have examined trapping of two-armed nearly vertical oscillations in polytropic disks. Two-armed nearly vertical oscillations are interesting in the sense that they are trapped i…
Leaving the ISCO: the inner edge of a black-hole accretion disk at various luminosities
Marek A. Abramowicz, Michal Jaroszynski, Shoji Kato +3
The "radiation inner edge" of an accretion disk is defined as the inner boundary of the region from which most of the luminosity emerges. Similarly, the "reflection edge" is the sm…
Resonant Excitation of Disk Oscillations in Two-Armed-Deformed Disks and Application to High-Frequency QPOs
Shoji Kato
In previous papers we showed that in a one-armed deformed disks, p-mode and g-mode oscillations are resonantly excited by horizontal resonance, and applied it to high frequency QPO…
Resonant Excitation of Disk Oscillations in Deformed Disks III: Revision of Mathematical Treatment
Shoji Kato
In previous studies, we have examined a resonant excitation of disk oscillations in deformed disks. In these studies, however, mathematical treatment around the resonant points was…
Frequency Correlation of QPOs Based on a Resonantly-Excited Disk-Oscillation Model
Shoji Kato
In previous papers, we have proposed a model that the high-frequency quasi-periodic oscillations (HF QPOs) observed in black-hole and neutron-star X-ray binaries are inertial-acous…
Resonant Excitation of Disk Oscillations in Deformed Disks II: A Model of High Frequency QPOs
Shoji Kato
The amplification of disk oscillations resulting from nonlinear resonant couplings between the oscillations and a disk deformation is examined. The disk is geometrically thin and g…
Frequency Correlations of QPOs Based on a Disk Oscillation Model in Warped Disks
Shoji Kato
In previous papers we proposed a model that high-frequency quasi-periodic oscillations (QPOs) observed in black-hole and neutron-star X-ray binaries are disk oscillations (inertial…