148 citations · 1.6k across the 38 of their papers we have counts for
23 papers · 1 filter
Inhomogeneous stellar mixing in the final hours before the Cassiopeia A supernova
Toshiki Sato, Kai Matsunaga, Hiroyuki Uchida +10
Understanding stars and their evolution is a key goal of astronomical research and has long been a focus of human interest. In recent years, theorists have paid much attention to t…
Evolution and explosions of metal enriched supermassive stars: proton rich general relativistic instability supernovae
Chris Nagele, Hideyuki Umeda, Koh Takahashi
The assembly of supermassive black holes poses a challenge primarily because of observed quasars at high redshift, but additionally because of the current lack of observations of i…
Pulsations of primordial supermassive stars induced by a general relativistic instability; visible to JWST at z12
Chris Nagele, Hideyuki Umeda, Koh Takahashi +1
The origin of high-redshift quasars and their supermassive black hole engines is unclear. One promising solution is the collapse of a primordial supermassive star. Observational co…
Neutrino emission from the collapse of population III supermassive stars
Chris Nagele, Hideyuki Umeda, Koh Takahashi +2
We calculate the neutrino signal from Population III supermassive star collapse using a neutrino transfer code originally developed for core collapse supernovae and massive star co…
Ultra-delayed neutrino-driven explosion of rotating massive-star collapse
Sho Fujibayashi, Koh Takahashi, Yuichiro Sekiguchi +1
Long-term neutrino-radiation hydrodynamics simulations in full general relativity are performed for the collapse of rotating massive stars that are evolved from He-stars with their…
Impact of binary interactions on the diffuse supernova neutrino background
Shunsaku Horiuchi, Tomoya Kinugawa, Tomoya Takiwaki +2
Binary interactions, especially mass transfer and mergers, can strongly influence the evolution of massive stars and change their final properties and the occurrence of supernovae.…
Pulsational pair-instability and the mass gap of Population III Black Holes: Effects of overshooting
Hideyuki Umeda, Takashi Yoshida, Chris Nagele +1
Since the discovery of GW190521, several proposals have been put forward to explain the formation of a black hole in the mass gap caused by (pulsational) pair-instability, $M = 65-…
The Final Fate of Supermassive Pop III Stars: Explosion or Collapse?
Chris Nagele, Hideyuki Umeda, Koh Takahashi +2
We investigate the possibility of a supernova in supermassive () population III stars induced by a general relativistic instability occurring in the helium…
First Detection of X-Ray Line Emission from Type IIn Supernova 1978K with XMM-Newton's RGS
Y. Chiba, S. Katsuda, T. Yoshida +2
We report on robust measurements of elemental abundances of the Type IIn supernova SN 1978K, based on the high-resolution X-ray spectrum obtained with the Reflection Grating Spectr…
Matter Mixing in Aspherical Core-collapse Supernovae: Three-dimensional Simulations with Single Star and Binary Merger Progenitor Models for SN 1987A
Masaomi Ono, Shigehiro Nagataki, Gilles Ferrand +5
We perform three-dimensional hydrodynamic simulations of aspherical core-collapse supernovae focusing on the matter mixing in SN 1987A. The impacts of four progenitor (pre-supernov…
Fitting formulae for evolution tracks of massive stars under extreme metal poor environments for population synthesis calculations and star cluster simulations
Ataru Tanikawa, Takashi Yoshida, Tomoya Kinugawa +2
We have devised fitting formulae for evolution tracks of massive stars with under extreme metal poor (EMP) environments for $\log (Z/Z_\odot) =…
Gravitational waves from very massive stars collapsing to a black hole
Haruki Uchida, Masaru Shibata, Koh Takahashi +1
We compute gravitational waves emitted by the collapse of a rotating very massive star (VMS) core leading directly to a black hole in axisymmetric numerical-relativity simulations.…
The Evolution towards Electron-capture Supernovae: the Flame Propagation and the Pre-bounce Electron-neutrino Radiation
K. Takahashi, K. Sumiyoshi, S. Yamada +2
A critical mass ONe core with a high ignition density is considered to end in gravitational collapse leading to neutron star formation. Being distinct from a Fe core collapse, the…
Black Hole Formation and Explosion from Rapidly Rotating Very Massive Stars
Haruki Uchida, Masaru Shibata, Koh Takahashi +1
We explore the formation process of a black hole (BH) through the pair-instability collapse of a rotating Population III very massive star in axisymmetric numerical relativity. As…
On the minimum mass of neutron stars
Yudai Suwa, Takashi Yoshida, Masaru Shibata +2
We investigate remnant neutron star masses (in particular, the minimum allowed mass) by performing advanced stellar evolution calculations and neutrino-radiation hydrodynamics simu…
The Low Detection Rate of Pair Instability Supernovae and the Effect of the Core Carbon Fraction
Koh Takahashi
The pair instability supernova (PISN) is a common fate of very massive stars (VMSs). Current theory predicts the initial and the CO core mass ranges for PISNe of 140-260 $M_\…
Explosive nucleosynthesis of ultra-stripped Type Ic supernovae: application to light trans-iron elements
Takashi Yoshida, Yudai Suwa, Hideyuki Umeda +2
We investigate the explosive nucleosynthesis during two dimensional neutrino-driven explosion of ultra-stripped Type Ic supernovae evolved from 1.45 and 1.5 M CO stars. The…
Ideal Engine Durations For Gamma-Ray-Burst-Jet Launch
Hamid Hamidani, Koh Takahashi, Hideyuki Umeda +1
Aiming to study GRB engine duration, we present numerical simulations to investigate collapsar jets. We consider typical explosion energy ( erg) but different engine durat…
Neutrino emissions in all flavors up to the pre-bounce of massive stars and the possibility of their detections
Chinami Kato, Hiroki Nagakura, Shun Furusawa +5
This paper is a sequel to our previous one (Kato et al.2015), which calculated the luminosities and spectra of electron-type anti-neutrinos ('s) from the progenitors of co…
Light-curve and spectral properties of ultra-stripped core-collapse supernovae leading to binary neutron stars
Takashi J. Moriya, Paolo A. Mazzali, Nozomu Tominaga +7
We investigate light-curve and spectral properties of ultra-stripped core-collapse supernovae. Ultra-stripped supernovae are the explosions of heavily stripped massive stars which…
Presupernova neutrino events relating to the final evolution of massive stars
Takashi Yoshida, Koh Takahashi, Hideyuki Umeda +1
When a supernova explosion occurs in neighbors around hundreds pc, current and future neutrino detectors are expected to observe neutrinos from the presupernova star before the exp…
Pre-supernova neutrino emissions from ONe cores in the progenitors of core-collapse supernovae: are they distinguishable from those of Fe cores?
Chinami Kato, Milad Delfan Azari, Shoichi Yamada +4
Aiming to distinguish two types of progenitors of core collapse supernovae, i.e., one with a core composed mainly of oxygen and neon (abbreviated as ONe core) and the other with an…
Neutrino-driven explosions of ultra-stripped type Ic supernovae generating binary neutron stars
Yudai Suwa, Takashi Yoshida, Masaru Shibata +2
We study explosion characteristics of ultra-stripped supernovae (SNe), which are candidates of SNe generating binary neutron stars (NSs). As a first step, we perform stellar evolut…