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Constraining the FRB Central Engine from Flux Variations of Persistent Radio Sources: FRB 20240114A as the First Attempt
Hirotaka Matsumiya, Kazumi Kashiyama, Tomonori Totani
Some repeating fast radio bursts (FRBs) are associated with persistent radio sources (PRSs), likely driven by the long-term activity of a central engine. We investigate FRB 2024011…
A Diagnostic Method for Proto-Neutron Star Magnetic Fields by Supernova Fallback Neutrinos
Akihiro Inoue, Yudai Suwa, Ryuichiro Akaho +3
Young isolated neutron stars exhibit a wide range of magnetic field strengths. To understand the origin of this diversity, it is important to observationally constrain magnetic fie…
A Type Ia Supernova Candidate at : A Transient Interloper in the Search for Galaxies
Seiji Toshikage, Takahiro Morishita, Masaomi Tanaka +9
The James Webb Space Telescope (JWST) is opening a new window into the distant Universe by discovering galaxies and transients in the early Universe. We investigate a high-redshift…
Blowouts of Nascent Wind Bubbles in Pulsar-Driven Supernovae
Mingxi Chen, Kazumi Kashiyama, Masato Sato
Formation of a rapidly spinning, strongly magnetized neutron star (NS) may occur in various classes of core-collapse events. If the NS injects an amount of energy comparable to the…
Super-knee cosmic rays from interacting supernovae
Nick Ekanger, Shigeo S. Kimura, Kazumi Kashiyama
There is increasing evidence that, in the very late phase of stellar evolution before core collapse, massive stars have winds with large mass loss rates that give rise to a dense c…
Successive Partial Disruptions with Orbital Precession in a White Dwarf-Black Hole System for Repeating GRB 250702B
Yuri Sato, Rin Oikawa, Kazuma Kato +2
The peculiar gamma-ray burst GRB 250702B is the longest event ever observed, lasting about one day and exhibiting four prompt-emission flares of s with irregular recurren…
Relaxation of time-variable neutron-loaded relativistic jets across the photosphere and their GeV-TeV neutrino counterparts
Kanako Nakama, Kazumi Kashiyama, Nobuhiro Shimizu
Both observational and theoretical studies indicate that the central engine of a gamma-ray burst (GRB) is intrinsically time-variable, implying jet inhomogeneity. A jet with an inh…
A Necessary Condition for the Submergence of Proto-Neutron Star Magnetic Fields by Supernova Fallback
Akihiro Inoue, Shinsuke Takasao, Kazumi Kashiyama +2
Central compact objects (CCOs) are a subclass of neutron stars with a dipole magnetic field strength considerably weaker than those of radio pulsars and magnetars. One possible exp…
EP240414a: A Gamma-Ray Burst Jet Weakened by an Extended Circumstellar Material
Hamid Hamidani, Yuri Sato, Kazumi Kashiyama +3
The recent Einstein Probe (EP) event EP240414a exhibits several unusual observational features. Its prompt and afterglow emissions place it between long gamma-ray bursts (LGRBs) an…
Gamma-Ray Burst Jets in Circumstellar Material: Dynamics, Breakout, and Diversity of Transients
Hamid Hamidani, Kunihito Ioka, Kazumi Kashiyama +1
Recent observations indicate that stripped-envelope core-collapse supernovae are often surrounded by dense circumstellar material (CSM). Motivated by this, we develop an analytic m…
Quasi-steady emission from repeating fast radio bursts can be explained by magnetar wind nebulae
Mukul Bhattacharya, Kohta Murase, Kazumi Kashiyama
Among more than 1000 known fast radio bursts (FRBs), only five sources - FRBs 20121102A, 20190520B, 20201124A, 20240114A and 20190417A - have confirmed associations with persistent…
On the X-ray efficiency of the white dwarf pulsar candidate ZTF J190132.9+145808.7
Aya Bamba, Yukikatsu Terada, Kazumi Kashiyama +3
Strongly magnetized, rapidly rotating massive white dwarfs (WDs) emerge as potential outcomes of double degenerate mergers. These WDs can act as sources of non-thermal emission and…
The optically thick rotating magnetic wind from a massive white dwarf merger product -- II. axisymmetric magnetohydrodynamic simulations
Yici Zhong, Kazumi Kashiyama, Shinsuke Takasao +2
We numerically construct a series of axisymmetric rotating magnetic wind solutions, aiming at exploring the observation properties of massive white dwarf (WD) merger remnants with…
Testing a stochastic acceleration model of pulsar wind nebulae: Early evolution of a wind nebula associated with SN 1986J
Shuta J. Tanaka, Kazumi Kashiyama
Over three thousand pulsars have been discovered, but none have been confirmed to be younger than a few hundred years. Observing a pulsar after a supernova explosion will help us u…
Gravitational Collapse of White Dwarfs to Neutron Stars. I. From Initial Conditions to Explosions with Neutrino-radiation Hydrodynamics Simulations
Masamitsu Mori, Ryo Sawada, Yudai Suwa +3
This paper provides collapses of massive, fully convective, and non-rotating white dwarfs (WDs) formed by accretion-induced collapse or merger-induced collapse and the subsequent e…
MASTER OT J030227.28+191754.5: a dwarf nova at a massive oxygen-neon white-dwarf system ?
Mariko Kimura, Kazumi Kashiyama, Toshikazu Shigeyama +3
We present timing and spectral analysis results of the {\it NICER} and {\it NuSTAR} observations of the dwarf nova MASTER OT J030227.28191754.5 during the 2021--2022 outburst. T…
X-raying the Birth of Binary Neutron Stars and Neutron Star-Black Hole Binaries
Kazumi Kashiyama, Ryo Sawada, Yudai Suwa
We consider fallback accretion after an ultra-stripped supernova (USSN) that accompanies formation of a binary neutron star (BNS) or a neutron star-black hole binary (NS-BH). The f…
Variable thermal energy injection from magnetar spin down as a possible cause of stripped-envelope supernova light-curve bumps
Takashi J. Moriya, Kohta Murase, Kazumi Kashiyama +1
Luminosity evolution of some stripped-envelope supernovae such as Type I superluminous supernovae is difficult to be explained by the canonical 56Ni nuclear decay heating. A popula…
On the energy source of ultra-stripped supernovae
Ryo Sawada, Kazumi Kashiyama, Yudai Suwa
Ultra-stripped supernovae (USSN) with a relatively low ejecta mass of (e.g., iPTF14gqr and SN2019dge) are considered to originate from ultra-stripped carbon-oxygen…
AT2018lqh: Black Hole Born from a Rotating Star?
Daichi Tsuna, Kazumi Kashiyama, Toshikazu Shigeyama
Recently an intriguing transient AT 2018lqh, with only a day-scale duration and a high luminosity of , has been discovered. While several possib…
Multi-wavelength emission from magnetically arrested disks around isolated black holes
Shigeo S. Kimura, Kazumi Kashiyama, Kenta Hotokezaka
We discuss the prospects for identifying nearest isolated black holes (IBHs) in our Galaxy. IBHs accreting gas from the interstellar medium (ISM) likely form magnetically arrested…
ALMA and NOEMA constraints on synchrotron nebular emission from embryonic superluminous supernova remnants and radio-gamma-ray connection
Kohta Murase, Conor M. B. Omand, Deanne L. Coppejans +8
Fast-rotating pulsars and magnetars have been suggested as the central engines of super-luminous supernovae (SLSNe) and fast radio bursts, and this scenario naturally predicts non-…
Multi-wavelength View of the Type IIn Zoo: Optical to X-ray Emission Model of Interaction-Powered Supernovae
Daichi Tsuna, Kazumi Kashiyama, Toshikazu Shigeyama
Transients powered by interaction with the circumstellar medium (CSM) are often observed in wavelengths other than optical, and multi-wavelength modelling can be important when inf…
Magnetically Arrested Disks in Quiescent Black-Hole Binaries: Formation Scenario, Observable Signatures, and Potential PeVatrons
Shigeo S. Kimura, Takahiro Sudoh, Kazumi Kashiyama +1
We propose magnetically arrested disks (MADs) in quiescent black-hole (BH) binaries as the origin of the multiwavelength emission, and argue that this class of sources can dominate…