74 citations · 292 across the 25 of their papers we have counts for
18 papers · 1 filter
Cosmic-Ray Spectra and Metal Budget Regulated by the Galactic Wind
Yusaku Fukumoto, Katsuaki Asano, Jiro Shimoda
We study the advection effect of the Galactic wind on the local cosmic ray spectra. The spectral hardening from a few hundred GV and softening from a few TV are reproduced by a vel…
Interplay between Escaping Cosmic Rays and Interstellar Medium: Driving of Galactic Winds and Shaping the Local Proton Spectrum
Jiro Shimoda, Katsuaki Asano, Shu-ichiro Inutsuka
We study the effects of escaping cosmic rays (CRs) on the interstellar medium (ISM) around their source with spherically symmetric CR-hydrodynamical simulations taking into account…
On Acceleration of Highest-Energy Cosmic Rays in a Novel Scenario of Magnetar Transients
Jiro Shimoda, Tomoki Wada
Transient phenomena in magnetars have been considered as possible acceleration sites of ultrahigh-energy cosmic-rays (CRs), whose energy reaches ~200 EeV, such as the Amaterasu par…
Large-scale Magnetic Field Model of GRB Afterglow Polarization: Effects of Field Anisotropy, Off-axis Viewing Angle, and Ordered Field
Asuka Kuwata, Kenji Toma, Sara Tomita +1
The afterglows of gamma-ray bursts are non-thermal electron synchrotron emissions from relativistic shocks. The origin of strong magnetic field in the emission region remains elusi…
Fermi and eROSITA Bubbles as Persistent Structures of the Milky Way
Jiro Shimoda, Katsuaki Asano
The Fermi and eROSITA bubbles, large diffuse structures in our Galaxy, can be the by-products of the steady star formation activity. To simultaneously explain the star formation hi…
The Dzhanibekov Effect as a Possible Source of Magnetar Activity
Tomoki Wada, Jiro Shimoda
Magnetars, which are neutron stars with strong magnetic fields, exhibit occasional bursting activities. The shape of a magnetar is not perfectly spherical due to the Lorentz force…
Simultaneous Radio and Optical Polarimetry of GRB 191221B Afterglow
Yuji Urata, Kenji Toma, Stefano Covino +16
Gamma-ray bursts (GRBs) are the most luminous transients in the universe and are utilized as probes of early stars, gravitational wave counterparts, and collisionless shock physics…
Synchrotron Polarization of Gamma-Ray Burst Afterglow Shocks with Hydrodynamic-scale Turbulent Magnetic Field
Asuka Kuwata, Kenji Toma, Shigeo S. Kimura +2
Afterglows of gamma-ray bursts (GRBs) are emitted from expanding forward shocks, which are expected to have magnetic field much stronger than the interstellar field, although the o…
X-ray Line Diagnostics of Ion Temperature at Cosmic-Ray Accelerating Collisionless Shocks
Jiro Shimoda, Yutaka Ohira, Aya Bamba +4
A novel collisionless shock jump condition is suggested by modeling the entropy production at the shock transition region. We also calculate downstream developments of the atomic i…
Multi-Wave band Synchrotron Polarization of Gamma-Ray Burst Afterglows
Jiro Shimoda, Kenji Toma
Multi-wave band synchrotron linear polarization of gamma-ray burst (GRB) afterglows is studied under the assumption of an anisotropic turbulent magnetic field with a coherence leng…
Diagnosing Cosmic Ray Modified Shocks with H α Polarimetry
Jiro Shimoda, J. Martin Laming
A novel diagnostic of cosmic-ray modified shocks by polarimetry of H emissions is suggested. In a cosmic-ray modified shock, the pressure of cosmic rays is sufficiently high co…
ALMA Polarimetry of AT2018cow
K. Y. Huang, J. Shimoda, Y. Urata +7
We present the first radio polarimetric observations of a fast-rising blue optical transient, AT2018cow. Two epochs of polarimetry with additional coincident photometry were perfor…
Radiative transfer of hydrogen lines from supernova remnant shock waves: contributions of 2s-state hydrogen atoms
Jiro Shimoda, J. Martin Laming
Radiative transfer in hydrogen lines in supernova remnant (SNR) shock waves is studied taking into account the population of the hydrogen atom 2s-state. Measurements of Balmer line…
Discovery of Kolmogorov-like Magnetic Energy Spectrum in Tycho's Supernova Remnant by Two-point Correlations of Synchrotron Intensity
Jiro Shimoda, Takuya Akahori, A. Lazarian +2
The spectral slope of the magnetic energy in supernova remnants (SNRs) can be obtained by analysis of spatial two-point correlation functions of synchrotron intensities. This metho…
Polarized Balmer Line Emission from Supernova Remnant Shock Waves Efficiently Accelerating Cosmic Rays
Jiro Shimoda, Yutaka Ohira, Ryo Yamazaki +2
Linearly polarized Balmer line emissions from supernova remnant shocks are studied taking into account the energy loss of the shock owing to the production of nonthermal particles.…
Spatially-Resolved Spectroscopy of a Balmer-Dominated Shock in the Cygnus Loop: An Extremely Thin Cosmic-Ray Precursor?
Satoru Katsuda, Keiichi Maeda, Yutaka Ohira +9
We present high-resolution long-slit spectroscopy of a Balmer-dominated shock in the northeastern limb of the Cygnus Loop with the Subaru high dispersion spectrograph. By setting t…
On cosmic-ray production efficiency at supernova remnant shocks propagating into realistic diffuse interstellar medium
Jiro Shimoda, Tsuyoshi Inoue, Yutaka Ohira +3
Using three-dimensional magnetohydrodynamics simulations, we show that the efficiency of cosmic-ray (CR) production at supernova remnants (SNRs) is over-predicted if it could be es…
Origin of Radially Aligned Magnetic Fields in Young Supernova Remnants
Tsuyoshi Inoue, Jiro Shimoda, Yutaka Ohira +1
It has been suggested by radio observations of polarized synchrotron emissions that downstream magnetic field in some young supernova remnants are oriented radially. We study magne…