Publications (11)
Expanding Fireball in Magnetar Bursts and Fast Radio Bursts
Tomoki Wada, Kunihito Ioka
A fireball of radiation plasma created near the surface of a neutron star (NS) expands under its own pressure along magnetic field lines, and produces photon emission and relativis…
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…
A Redox-based Ion-Gating Reservoir, Utilizing Double Reservoir States in Drain and Gate Nonlinear Responses
Tomoki Wada, Daiki Nishioka, Wataru Namiki +3
We have demonstrated physical reservoir computing with a redox-based ion-gating reservoir (redox-IGR) comprising LixWO3 thin film and lithium ion conducting glass ceramic (LICGC).…
Constraints on the Physical Association between ICECAT1 Neutrinos and Fast Radio Bursts Using the Second CHIME/FRB Catalogue
Hiroto Masaoka, Tetsuya Hashimoto, Shotaro Yamasaski +8
We present a search for neutrino counterparts to fast radio bursts (FRBs) using temporal and spatial cross-matching between the Second CHIME/FRB catalogue and the IceCube high-ener…
Analytic properties of electromagnetic field of binary compact stars and electromagnetic precursors to gravitational waves
Tomoki Wada, Masaru Shibata, Kunihito Ioka
We analytically study the properties of the electromagnetic field in vacuum around close binary compact stars containing at least one neutron star. We show that the orbital motion…
Unveiling Hidden Clustering: An Unsupervised Machine Learning Study of Repeating FRB 20220912A
An-Chieh Hsu, Tetsuya Hashimoto, Tomotsugu Goto +2
Fast Radio Bursts (FRBs) are millisecond-duration radio transients of extragalactic origin. Classifying repeating FRBs is essential for understanding their emission mechanisms, but…
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…
Spectral Shapes of Pair Annihilation Line Emission in Magnetar Giant Flares
Tomoki Wada, Shigeo S. Kimura
We investigate the gamma-ray spectrum in the MeV range arising from electron-positron pair annihilation in fireballs associated with magnetar giant flares (MGFs), motivated by the…
Vacuum Polarization Effects in Baryon-Loaded Magnetar Bursts and Implications for X-ray Polarization
Tomoki Wada
Magnetars provide natural laboratories for strong-field quantum electrodynamics processes, such as vacuum polarization, which gives rise to vacuum resonance together with the plasm…
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…
Binary comb models for FRB 121102
Tomoki Wada, Kunihito Ioka, Bing Zhang
The first repeating fast radio burst source, FRB 121102, is observed to emit bursts periodically. We show that FRB 121102 can be interpreted as an interacting neutron star binary s…