220 citations · 1.1k across the 33 of their papers we have counts for
33 papers
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…
The Impact of Angular Momentum Loss on the Outcomes of Binary Mass Transfer
Reinhold Willcox, Morgan MacLeod, Ilya Mandel +1
We use the rapid binary population synthesis code COMPAS to investigate commonly used prescriptions for the determination of mass transfer stability in close binaries and the orbit…
Roman CCS White Paper: Characterizing the Galactic population of isolated black holes
Casey Y. Lam, Natasha Abrams, Jeff Andrews +34
Although there are estimated to be 100 million isolated black holes (BHs) in the Milky Way, only one has been found so far, resulting in significant uncertainty about their propert…
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…
Constraining mass transfer and common-envelope physics with post-supernova companion monitoring
Ryosuke Hirai
We present an analytical model that describes the response of companion stars after being impacted by a supernova in a close binary system. This model captures key properties of th…
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…
The Galactic Underworld: The spatial distribution of compact remnants
David Sweeney, Peter Tuthill, Sanjib Sharma +1
We chart the expected Galactic distribution of neutron stars and black holes. These compact remnants of dead stars -- the Galactic underworld -- are found to exhibit a fundamentall…
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…
Common envelopes in massive stars II: The distinct roles of hydrogen and helium recombination
Mike Y. M. Lau, Ryosuke Hirai, Daniel J. Price +1
The role of recombination during a common-envelope event has been long debated. Many studies have argued that much of hydrogen recombination energy, which is radiated in relatively…
Common envelope binary interaction simulations between a thermally-pulsating AGB star and a low mass companion
Miguel Gonzalez-Bolivar, Orsola De Marco, Mike Y. M. Lau +2
At least one in five of all planetary nebulae are the product of a common envelope (CE) interaction, where the companion in-spirals into the envelope of an asymptotic giant branch…
An environmental analysis of the Type Ib SN 2019yvr and the possible presence of an inflated binary companion
Ning-Chen Sun, Justyn R. Maund, Paul A. Crowther +5
SN 2019yvr is the second Type Ib supernova (SN) with a possible direct detection of its progenitor (system); however, the spectral energy distribution (SED) of the pre-explosion so…
Common envelopes in massive stars: Towards the role of radiation pressure and recombination energy in ejecting red supergiant envelopes
Mike Y. M. Lau, Ryosuke Hirai, Miguel González-Bolívar +3
We perform 3D hydrodynamical simulations of a common-envelope event involving a 12 solar mass red supergiant donor. Massive stars are expected to be qualitatively different from lo…
Rapid stellar and binary population synthesis with COMPAS
Team COMPAS, :, Jeff Riley +23
Compact Object Mergers: Population Astrophysics and Statistics (COMPAS; https://compas.science) is a public rapid binary population synthesis code. COMPAS generates populations of…
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…
Observability of inflated companion stars after supernovae in massive binaries
Misa Ogata, Ryosuke Hirai, Kotaro Hijikawa
We carry out a systematic study of the response of companion stars in massive binaries after being impacted by supernova ejecta. A total of 720 1D stellar evolution calculations ar…
Wind mass-loss rates of stripped stars inferred from Cygnus X-1
Coenraad J. Neijssel, Serena Vinciguerra, Alejandro Vigna-Gomez +5
Recent observations of the high-mass X-ray binary Cygnus X-1 have shown that both the companion star (41 solar masses) and the black hole (21 solar masses) are more massive than pr…
Simulating the formation of Carinae's surrounding nebula through unstable triple evolution and stellar merger-induced eruption
Ryosuke Hirai, Philipp Podsiadlowski, Stanley P. Owocki +2
Carinae is an extraordinary massive star famous for its 19th century Great Eruption and the surrounding Homunculus nebula ejected in that event. The cause of this eruption has…
Formation pathway for lonely stripped-envelope supernova progenitors: implications for Cassiopeia A
Ryosuke Hirai, Toshiki Sato, Philipp Podsiadlowski +2
We explore a new scenario for producing stripped-envelope supernova progenitors. In our scenario, the stripped-envelope supernova is the second supernova of the binary, in which th…
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…
Origins of Type Ibn SNe 2006jc/2015G in interacting binaries and implications for pre-SN eruptions
Ning-Chen Sun, Jusytn R. Maund, Ryosuke Hirai +2
Type Ibn supernovae (SNe Ibn) are intriguing stellar explosions whose spectra exhibit narrow helium lines with little hydrogen. They trace the presence of circumstellar material (C…