41 citations · 189 across the 21 of their papers we have counts for
21 papers
Measurements of magnetic fields in circumnuclear matter with the SKA telescopes
Satoko Sawada-Satoh, Yuki Kudoh
Magnetic fields are thought to regulate the angular momentum transfer in active galactic nuclei (AGNs), yet their strength and structure in circumnuclear regions remain poorly cons…
Probing the Parsec-Scale Dynamical Structure of Ionized Gas in Radio-Quiet AGN with SKA
Yuki Kudoh, Satoko Sawada-Satoh
We systematically organize the radio-emitting components in radio-quiet active galactic nuclei (RQ AGN), including jets, accretion disk coronae, dust, ionized gas outflows, and cir…
Unification Model of Active Galactic Nuclei by Photoionization Equilibrium Calculation Based on Radiative Hydrodynamic Simulations
Atsushi Tanimoto, Keiichi Wada, Yuki Kudoh +3
To investigate the origin of the dependence of the covering factor on the Eddington ratio suggested by X-ray observations, we examined the angular distribution of HI and HII based…
X-Ray Radiative Transfer Calculation Based on a Physics-based Model of the Sub-parsec-scale Gases around an Active Galactic Nucleus and Its Application to NGC 3783
Atsushi Tanimoto, Keiichi Wada, Hirokazu Odaka +2
Although the X-ray spectra of Seyfert 1 galaxies exhibit absorption lines of He-like iron and H-like iron at blue-shifted velocities of approximately $500 \ \mathrm{km} \ \mathrm{s…
Formation and Early Evolution of Protoplanetary Disks under Nonuniform Cosmic-Ray Ionization
Erika Nishio, Kengo Tomida, Yuki Kudoh +1
Angular momentum transport by magnetic fields is important for formation and evolution of protoplanetary disks. The effects of magnetic fields are suppressed due to non-ideal magne…
Multiphase Gas Nature in the Sub-parsec Region of the Active Galactic Nuclei. III. Eddington Ratio Dependence on the Structures of Dusty and Dust-free Outflows
Yuki Kudoh, Keiichi Wada, Nozomu Kawakatu +1
We investigated the influence of the Eddington ratio on sub-parsec-scale outflows in active galactic nuclei (AGNs) with supermassive black holes (SMBHs) masses of M$_{\odot}…
Circumnuclear Multi-phase Gas in the Circinus Galaxy. VI. Detectability of Molecular Inflow and Atomic Outflow
Shunsuke Baba, Keiichi Wada, Takuma Izumi +2
Recent submillimeter observations have revealed signs of pc-scale molecular inflow and atomic outflow in the nearest Seyfert 2 galaxy, the Circinus galaxy. To verify the gas kinema…
Circumnuclear Multi-phase Gas in the Circinus Galaxy. V. The Origin of the X-Ray Polarization in the Circinus Galaxy
Atsushi Tanimoto, Keiichi Wada, Yuki Kudoh +3
The Imaging X-ray Polarimetry Explorer (IXPE) detected X-ray polarization in the nearest Seyfert 2 galaxy, the Circinus galaxy, for the first time. To reproduce the IXPE results, w…
Multiphase Gas Nature in the Sub-parsec Region of the Active Galactic Nuclei I: Dynamical Structures of Dusty and Dust-free Outflow
Yuki Kudoh, Keiichi Wada, Nozomu Kawakatu +1
We investigated dusty and dust-free gas dynamics for a radiation-driven sub-pc scale outflow in an active galactic nucleus (AGN) associated with a supermassive black hole $10^7 M_\…
Supermassive black hole feeding and feedback observed on sub-parsec scales
Takuma Izumi, Keiichi Wada, Masatoshi Imanishi +8
Active galaxies contain a supermassive black hole at their center, which grows by accreting matter from the surrounding galaxy. The accretion process in the central ~10 parsecs has…
Multi-phase gas nature in the sub-pc region of the active galactic nuclei II: Possible origins of the changing-state AGNs
Keiichi Wada, Yuki Kudoh, Tohru Nagao
Multi-wavelength observations of active galactic nuclei (AGNs) often reveal various time scales of variability. Among these phenomena, "changing-look AGNs" are extreme cases where…
Probing dynamics and thermal properties inside molecular tori with CO rovibrational absorption lines
Kosei Matsumoto, Takao Nakagawa, Keiichi Wada +5
A recent hydrodynamic model, "radiation-driven fountain model" (Wada et al. 2016), presented a dynamical picture that active galactic nuclei (AGNs) tori sustain their geometrical t…
Circumnuclear Multi-phase Gas in Circinus Galaxy IV: absorption owing to high- CO rotational transitions
Taisei Uzuo, Keiichi Wada, Takuma Izumi +3
We studied the absorption features of CO lines against the continuum originating from the heated dust in the obscuring tori around active galactic nuclei (AGNs). We investigated th…
Large-scale magnetic field structure of NGC 3627 based on magnetic vector map
Kohei Kurahara, Hiroyuki Nakanishi, Yuki Kudoh
We analyzed the data of Stokes , , and in C- and X-bands and investigated the large-scale magnetic field structure of NGC 3627. The polarization intensity and angle in ea…
Multiphase Circumnuclear Gas in a Low- Disk: Turbulence and Magnetic Field Reversals
Yuki Kudoh, Keiichi Wada, Colin Norman
We studied the magnetic field structures and dynamics of magnetized multiphase gas on parsec scales around supermassive black holes by using global 3D magnetohydrodynamics (MHD) si…
Two-temperature Magnetohydrodynamic simulations for sub-relativistic AGN jets:Dependence on the fraction of the electron heating
T. Ohmura, M. Machida, K. E. Nakamura +2
We present the results of two-temperature magnetohydrodynamic simulations of the propagation of sub-relativistic jets of active galactic nuclei. The dependence of the electron and…
Magneto Rotational Instability in Magnetized AGN Tori
Yuki Kudoh, Keiichi Wada
It is widely believed that in active galactic nuclei (AGNs) a supermassive black hole with an accretion disk is surrounded by an optically and geometrically thick torus at sub-pars…
Cosmic Magnetism in Centimeter and Meter Wavelength Radio Astronomy
Takuya Akahori, Hiroyuki Nakanishi, Yoshiaki Sofue +13
Magnetic field is ubiquitous in the Universe and it plays essential roles in various astrophysical phenomena, yet its real origin and evolution are poorly known. This article revie…
Magnetohydrodynamic Simulation Code CANS+: Assessments and Applications
Yosuke Matsumoto, Yuta Asahina, Yuki Kudoh +7
We present a new magnetohydrodynamic (MHD) simulation code with the aim of providing accurate numerical solutions to astrophysical phenomena where discontinuities, shock waves, and…
Approximate Riemann Solvers for the Cosmic Ray Magnetohydrodynamical Equations
Yuki Kudoh, Tomoyuki Hanawa
We analyze the cosmic-ray magnetohydrodynamic (CR MHD) equations to improve the numerical simulations. We propose to solve them in the fully conservation form, which is equivalent…
Resolving 4-D Nature of Magnetism with Depolarization and Faraday Tomography: Japanese SKA Cosmic Magnetism Science
Takuya Akahori, Yutaka Fujita, Kiyotomo Ichiki +9
Magnetic fields play essential roles in various astronomical objects. Radio astronomy has revealed that magnetic fields are ubiquitous in our Universe. However, the real origin and…