220 citations · 1.1k across the 33 of their papers we have counts for
16 papers · 1 filter
Neutron star kicks plus rockets as a mechanism for forming wide low-eccentricity neutron star binaries
Ryosuke Hirai, Philipp Podsiadlowski, Alexander Heger +1
Recent neutron star surface observations corroborate a long-standing theory that neutron stars may be accelerated over extended periods after their birth. We analyze how these prol…
Time-independent Simulations of Steady-State Accretion with Nuclear Burning
Kaho Tse, Alexander Heger, Ryosuke Hirai +1
We construct a new formulation that allows efficient exploration of steady-state accretion processes onto compact objects. Accretion onto compact objects is a common scenario in as…
Rapid population synthesis of black-hole high-mass X-ray binaries: implications for binary stellar evolution
Isobel M. Romero-Shaw, Ryosuke Hirai, Arash Bahramian +2
We conduct binary population synthesis to investigate the formation of wind-fed high-mass X-ray binaries containing black holes (BH-HMXBs). We evolve multiple populations of high-m…
Neutron stars colliding with binary companions: formation of hypervelocity stars, pulsar planets, bumpy superluminous supernovae and Thorne-Żytkow objects
Ryosuke Hirai, Philipp Podsiadlowski
We perform 3D hydrodynamical simulations of new-born neutron stars (NSs) colliding with main-sequence binary companions after supernova explosions. Based on those hydrodynamical mo…
Stellar Core-Merger-Induced Collapse: New Formation Pathways for Black Holes, Thorne-ytkow objects, Magnetars and Superluminous Supernovae
Iminhaji Ablimit, Philipp Podsiadlowski, Ryosuke Hirai +1
Most neutron stars (NSs) and black holes (BHs) are believed to be the final remnants in the evolution of massive stars. In this study, we propose a new formation channel for the fo…
Conditions for accretion disc formation and observability of wind-accreting X-ray binaries
Ryosuke Hirai, Ilya Mandel
We explore the effect of anisotropic wind driving on the properties of accretion onto black holes in close binaries. We specifically focus on line-driven winds, which are common in…
Supernova explosions in active galactic nuclear discs
Evgeni Grishin, Alexey Bobrick, Ryosuke Hirai +2
Active galactic nuclei (AGN) are prominent environments for stellar capture, growth and formation. These environments may catalyze stellar mergers and explosive transients, such as…
Neutron Star Extreme Matter Observatory: A kilohertz-band gravitational-wave detector in the global network
K. Ackley, V. B. Adya, P. Agrawal +160
Gravitational waves from coalescing neutron stars encode information about nuclear matter at extreme densities, inaccessible by laboratory experiments. The late inspiral is influen…
The sensitivity of presupernova neutrinos to stellar evolution models
Chinami Kato, Ryosuke Hirai, Hiroki Nagakura
We examine the sensitivity of neutrino emissions to stellar evolution models for a 15 progenitor, paying particular attention to a phase prior to the collapse. We demonstr…
A Sub-Solar Metallicity Progenitor for Cassiopeia A, the remnant of a Type IIb Supernova
Toshiki Sato, Takashi Yoshida, Hideyuki Umeda +7
We report, for the first time, the detection of the Mn-K line in the Type IIb supernova (SN IIb) remnant, Cassiopeia A. Manganese (Mn after decay of Co), a neutron…
Comprehensive study of ejecta-companion interaction for core-collapse supernovae in massive binaries
Ryosuke Hirai, Philipp Podsiadlowski, Shoichi Yamada
We carry out a comprehensive study of supernova ejecta-companion interaction in massive binary systems. We aim to physically understand the kinematics of the interaction and predic…
The Origin of the Possible Massive Black Hole in the Progenitor System of iPTF13bvn
Ryosuke Hirai
This letter complements a formation scenario of the progenitor of the supernova iPTF13bvn proposed in Hirai (2017). Although the scenario was successful in reproducing various obse…
Formation Scenario of the Progenitor of iPTF13bvn Revisited
Ryosuke Hirai
The formation scenario of the progenitor of iPTF13bvn has been revisited. iPTF13bvn is unique in the sense that a corresponding pre-supernova image has been identified. This has en…
Formation pathway of Population III coalescing binary black holes through stable mass transfer
Kohei Inayoshi, Ryosuke Hirai, Tomoya Kinugawa +1
We study formation of stellar mass binary black holes (BBHs) originating from Population III (PopIII) stars, performing stellar evolution simulations for PopIII binaries with MESA.…
Possible Signatures of Ejecta-Companion Interaction in iPTF 13bvn
Ryosuke Hirai, Shoichi Yamada
We investigate the possible effects of the supernova ejecta hitting the companion star in iPTF 13bvn, focusing on the observable features when it becomes visible. iPTF 13bvn is a t…
The Outcome of Supernovae in Massive Binaries; Removed Mass, and its Separation Dependence
Ryosuke Hirai, Hidetomo Sawai, Shoichi Yamada
The majority of massive stars are formed in binary systems. It is hence reasonable to expect that most core-collapse supernovae (CCSNe) take place in binaries and the existence of…