256 citations · 2.5k across the 78 of their papers we have counts for
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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…
Spectral Uniformity of Little Red Dots: A Natural Outcome of Coevolving Seed Black Holes and Nascent Starbursts
Kohei Inayoshi, Kohta Murase, Kazumi Kashiyama
The birth of seeds of massive black holes (BHs) and nascent galaxies at cosmic dawn takes place in dense gaseous environments, which play a crucial role in shaping their coevolutio…
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…