8 citations · 17 across the 11 of their papers we have counts for
11 papers
Radiative Efficiency Enhancement by Electromagnetic Energy Dissipation in Strongly Magnetized Supercritical Accretion Flows around Kerr Black Holes
Hiroyuki R. Takahashi, Ken Ohsuga, Ryohei Kobayashi +4
We investigate how black hole spin and the amount of magnetic flux affect electromagnetic energy dissipation and radiation transport in supercritical accretion flows. For this purp…
Black Hole Explorer Mission Development in Japan
Kazunori Akiyama, Mareki Honma, Akihiro Doi +21
The Black Hole Explorer (BHEX) is a next-generation space very-long-baseline interferometry (VLBI) mission concept that will extend existing ground-based millimeter/submillimeter V…
Black Hole Spin Estimation with Time-variable Image of M87 During the Flaring State
Mikiya M. Takahashi, Tomohisa Kawashima, Ken Ohsuga
By investigating the time-variable 230 GHz images using ray-tracing general relativistic radiative transfer calculation, we propose a novel method for estimating the spin parameter…
Constraining the Corona Geometry of Cyg X-1 with Broad Band Spectrum and Polarimetric Analysis Based on Observations in May 2022
Sixuan Zhang, Tsunefumi Mizuno, Tomohisa Kawashima +6
Cygnus X-1 (Cyg X-1) exhibited a low hard state in 2022, observed by several missions. The IXPE reported that the polarization angle is aligned with the radio jet and gave a polari…
Clumpy Outflows from Super-Eddington Accreting Black Holes I: Radiation Hydrodynamics Simulations and Observational Implications
Haojie Hu, Yuta Asahina, Shogo Yoshioka +2
Recent advances in X-ray spectroscopic observation have enabled researchers to reveal distinct clumpy structures in the super-Eddington outflows from the supermassive black hole in…
Survey of Non-thermal Electron around Supermassive Black Holes through Polarization Flips
Yuh Tsunetoe, Tomohisa Kawashima, Ken Ohsuga +1
Optically thick non-thermal synchrotron sources notably produce linear polarization vectors being parallel to projected magnetic field lines on the observer's screen, although they…
Radiation and outflow properties of super-Eddington accretion flows around various mass classes of black holes: Dependence on the accretion rates
Shogo Yoshioka, Shin Mineshige, Ken Ohsuga +2
We perform axisymmetric two-dimensional radiation-hydrodynamic simulations of super-Eddington accretion flow and outflow around black holes to examine the properties of radiation a…
Radiation MHD Simulations of Soft X-ray Emitting Regions in Changing Look AGN
Taichi Igarashi, Hiroyuki R. Takahashi, Tomohisa Kawashima +3
Strong soft X-ray emission called soft X-ray excess is often observed in luminous active galactic nuclei (AGN). It has been suggested that the soft X-rays are emitted from a warm (…
Black Hole Spacetime and Properties of Accretion Flows and Jets Probed by Black Hole Explorer: Science Cases Proposed by BHEX Japan Team
Tomohisa Kawashima, Yuh Tsunetoe, Ken Ohsuga +7
Black Hole Explorer (BHEX) is a space VLBI mission concept, which can probe the black hole spacetime and the plasma properties including the magnetic fields of the accretion flows…
The Japanese Vision for the Black Hole Explorer Mission
Kazunori Akiyama, Kotaro Niinuma, Kazuhiro Hada +43
The Black Hole Explorer (BHEX) is a next-generation space very long baseline interferometry (VLBI) mission concept that will extend the ground-based millimeter/submillimeter arrays…
A Relativistic Formula for the Multiple Scattering of Photons
Rohta Takahashi, Masayuki Umemura, Ken Ohsuga +6
We have discovered analytical expressions for the probability density function (PDF) of photons that are multiply scattered in relativistic flows, under the assumption of isotropic…