30 citations · 94 across the 20 of their papers we have counts for
21 papers
CROMA: a GPU-accelerated Fokker--Planck solver for modeling non-thermal emission in post-processing cosmological simulations
Kosuke Nishiwaki, Claudio Gheller, Gianfranco Brunetti +1
Numerical modeling of cosmic-ray (CR) spectra and the resulting non-thermal emission is important for understanding the physical mechanisms of CR acceleration and transport in astr…
Revisiting early afterglows of gamma-ray bursts with finite-thickness ejecta: Implications from XRF 080330 and GRB 080710
Kaori Obayashi, Ryo Yamazaki, Yo Kusafuka +1
We revisit the physical origin of the achromatic peaks and breaks observed several thousand seconds after the burst in the multi-wavelength afterglows of XRF 080330 and GRB 080710.…
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…
Double-Peaked Optical Afterglow in GRB 110213A Inferring a Magnetized Thick Shell Ejecta
Yo Kusafuka, Kaori Obayashi, Katsuaki Asano +1
Gamma-ray bursts early afterglows are important tracers for determining the radial structure and magnetization of the ejecta. In this paper, we focus on GRB 110213A that shows doub…
Interpreting the multi-TeV emission from GRB 221009A with a second electron component accelerated by turbulence in the jet
Xing-Wei Gong, Ruo-Yu Liu, Ze-Lin Zhang +2
The detection of very high-energy (VHE) afterglow emission of the gamma-ray burst (GRB) 221009A by the Large High Altitude Air Shower Observatory (LHAASO) provides a unique opportu…
Evidence for GeV Gamma-Ray Emission from Intense GRB 240529A During the Afterglow's Shallow Decay Phase
Kenta Terauchi, Tomohiko Oka, Katsuaki Asano
X-ray light curves of gamma-ray burst (GRB) afterglows exhibit various features, with the shallow decay phase being particularly puzzling. While some studies report absence of the…
High-Energy Neutrino Emission from a Radiatively Inefficient Accretion Flow with a three-dimensional GRMHD Simulation
Tomohisa Kawashima, Katsuaki Asano
The high-energy particle production in the accretion flow onto black holes can be a key physics to explain the high-energy neutrino background. While the single-zone approximation…
TeV Afterglow of BOAT GRB without Jet Break
Yo Kusafuka, Katsuaki Asano
We present a new model for the TeV afterglow of GRB 221009A. The rapid increase of the TeV flux in the very early phase is reproduced by the magnetic acceleration. We consider the…
Low injection rate of cosmic-ray protons in the turbulent reacceleration model of radio halos in galaxy clusters
Kosuke Nishiwaki, Katsuaki Asano
A giant radio halo (RH) is a diffuse synchrotron emission observed on the scale of megaparsecs (Mpc), typically found in the central region of merging galaxy clusters. Its large si…
Ejecta Width and Magnetization Reflected in Gamma-Ray Burst Early Afterglows: Implication for Reverse Shock Component and Shallow Decay Phase
Yo Kusafuka, Katsuaki Asano
To study the ejecta property dependence of the gamma-ray burst (GRB) afterglow, we carry out spherically symmetrical one-dimensional special relativistic magneto-hydrodynamic simul…
Possible X-ray Cocoon Emission from GRB 050709
Naoki Ogino, Makoto Arimoto, Hamid Hamidani +6
The detection of the short gamma-ray burst (SGRB) 050709 by the HETE-2 satellite opened a new window into understanding the nature of SGRBs, offering clues about their emission mec…
Multiwavelength Modeling for the Shallow Decay Phase of Gamma-Ray Burst Afterglows
Katsuaki Asano
We simulate the emission in the shallow decay phase of gamma-ray burst afterglows using a time-dependent code. We test four models: the energy injection model, evolving the injecti…
Radiation Process in Relativistic MHD Waves: the Case of Circularly Polarized Alfvén Wave
Ryota Goto, Katsuaki Asano
Turbulence in highly magnetized plasma can be relativistic and induce an electric field comparable to the background magnetic field. Such a strong electric field can affect the emi…
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…
Radiative Acceleration and X-ray Spectrum of Outflowing Pure Electron-Positron Pair Fireball in Magnetar Bursts
Tomoki Wada, Katsuaki Asano
An X-ray short burst associated with a Galactic fast radio burst was observed in 2020, distinguished by its X-ray cut-off energy significantly exceeding that of other X-ray short b…
Gamma rays from a reverse shock with turbulent magnetic fields in GRB 180720B
Makoto Arimoto, Katsuaki Asano, Koji S. Kawabata +14
Gamma-ray bursts (GRBs) are the most electromagnetically luminous cosmic explosions. They are powered by collimated streams of plasma (jets) ejected by a newborn stellar-mass black…
Testing blazar emission models on the extreme blazar PGC 2402248, newly discovered at very high energies with the MAGIC telescopes
L. Foffano, J. Becerra Gonzalez, M. Cerruti +5
Extreme high-energy peaked BL Lac objects (EHBLs) are a new emerging class of blazars. The typical two-hump structured spectral energy distribution (SED) is shifted to higher energ…
A Unified Model for GRB Prompt Emission from Optical to -Rays: Exploring GRBs as Standard Candles
S. Guiriec, C. Kouveliotou, D. H. Hartmann +6
The origin of prompt emission from gamma ray bursts remains to be an open question. Correlated prompt optical and gamma-ray emission observed in a handful of GRBs strongly suggests…
Photon and Neutrino Spectra of Time-Dependent Photospheric Models of Gamma-Ray Bursts
K. Asano, P. Mészáros
Thermal photons from the photosphere may be the primary source of the observed prompt emission of gamma-ray bursts (GRBs). In order to produce the observed non-thermal spectra, som…
Spectral Lag Relations in GRB Pulses Detected with HETE-2
M. Arimoto, N. Kawai, K. Asano +36
Using a pulse-fit method, we investigate the spectral lags between the traditional gamma-ray band (50-400 keV) and the X-ray band (6-25 keV) for 8 GRBs with known redshifts (GRB 01…