Nucleosynthesis in Magnetically Driven Jets from Collapsars (2008)
Fujimoto, Shin-ichiro, Nishimura, Nobuya, Hashimoto, Masa-aki
We have made detailed calculations of the composition of magnetically driven jets ejected from collapsars, or rapidly rotating massive stars, based on long-term magnetohydrodynamic simulations of...
Nakamura, Riou, Hashimoto, Masa-aki, Ichiki, Kiyotomo
We constrain the thermal evolution of the universe with a decaying cosmological term by using the method of the analysis for the Wilkinson Microwave Anisotropy Probe (WMAP) observation data. The...
Reply to 'Comment on 'Heavy element production in inhomogeneous big bang nucleosynthesis'' (2007)
Matsuura, Shunji, Fujimoto, Shin-ichirou, Hashimoto, Masa-aki, Sato, Katsuhiko
This is a reply report to astro-ph/0604264. We studied heavy element production in high baryon density region in early universe astro-ph/0507439. However it is claimed in astro-ph/0604264 that small...
Yasutake, Nobutoshi, Kotake, Kei, Hashimoto, Masa-aki, Yamada, Shoichi
We perform two-dimensional, magnetohydrodynamical core-collapse simulations of massive stars accompanying the QCD phase transition. We study how the phase transition affects the gravitational...
Observational constraints on a decaying cosmological term (2006)
Nakamura, Riou, Hashimoto, Masa-aki, Ichiki, Kiyotomo
We investigate the evolution of a universe with a decaying cosmological term (vacuum energy) that is assumed to be a function of the scale factor. In this model, while the cosmological term increases...
Magnetohydrodynamic Simulations of A Rotating Massive Star Collapsing to A Black Hole (2006)
Fujimoto, Shin-ichiro, Kotake, Kei, Yamada, Shoichi, Hashimoto, Masa-aki, Sato, Katsuhiko
We perform two-dimensional, axisymmetric, magnetohydrodynamic simulations of the collapse of a rotating star of 40 Msun and in the light of the collapsar model of gamma-ray burst. Considering two...
Heavy element nucleosynthesis in a collapsar (2006)
Fujimoto, Shin-ichirou, Hashimoto, Masa-aki, Kotake, Kei, Yamada, Shoichi
We investigate synthesis of heavy elements in a collapsar. We have calculated detailed composition of magnetically driven jets ejected from a collapsar, which is based on long-term,...
R-Process Nucleosynthesis in MHD Jet Explosions of Core-Collapse Supernovae (2005)
Nishimura, Sunao, Kotake, Kei, Hashimoto, Masa-aki, Yamada, Shoichi, Nishimura, Nobuya, Fujimoto, Shinichiro, ...
We investigate $r$-process nucleosynthesis during the magnetohydrodynamical (MHD) explosion of supernova in a massive star of 13 $M_{\odot}$. Contrary to the case of the spherical explosion, jet-like...
Yasutake, Nobutoshi, Hashimoto, Masa-aki, Eriguchi, Yoshiharu
We present a scenario of formation of strange stars due to spin-down of {\it rapidly rotating} neutron stars left after supernova explosions . By assuming a process where the total baryon mass is...
Hypernova Nucleosynthesis and Implications for Cosmic Chemical Evolution (2001)
Nakamura, Takayoshi, Umeda, Hideyuki, Iwamoto, Koichi, Nomoto, Ken'ichi, Hashimoto, Masa-aki, Hix, W. Raphael, ...
We examine the characteristics of nucleosynthesis in 'hypernovae', i.e., supernovae with very large explosion energies ($\gsim 10^{52}$ ergs). Implications for the cosmic chemical evolution and the...
Explosive Nucleosynthesis in Hypernovae (2000)
Nakamura, Takayoshi, Umeda, Hideyuki, Iwamoto, Koichi, Nomoto, Ken'ichi, Hashimoto, Masa-aki, Hix, W. Raphael, ...
We examine the characteristics of nucleosynthesis in 'hypernovae', i.e., supernovae with very large explosion energies ($ \gsim 10^{52} $ ergs). We carry out detailed nucleosynthesis calculations for...
Explosive Nucleosynthesis in Axisymmetrically Deformed Type II Supernovae (1997)
Nagataki, Shigehiro, Hashimoto, Masa-aki, Sato, Katsuhiko, Yamada, Shoichi
Explosive nucleosynthesis under the axisymmetric explosion in Type II supernova has been performed by means of two dimensional hydrodynamical calculations. We have compared the results with the...