Year: 2026
Type: preprint
Abstract: Standard models for stellar core collapse predict the birth of neutron stars with masses exceeding a solar mass. In the collapsar model, a rapidly rotating massive star collapses to a black hole surrounded by a dense, neutrino-cooled accretion disk, whose outer regions may in some cases fragment into neutron-rich clumps that collapse to form subsolar-mass neutron stars. These disk-formed objects can then merge either with one another or, following possibly hierarchical evolution, with the central black hole. In this work, we characterize the gravitational-wave signatures of these binaries, focusing on distinctive features of the collapsar environment: Doppler and other phase modulations from orbital motion about the central black hole, gas-driven migration in the disk, and tidal interactions during inspiral. We show that the combination of anomalously low component masses with these environmental imprints produces unique waveform signatures that can distinguish the collapsar channel from other subsolar merger scenarios. Current and next-generation detectors have good prospects for identifying the intrinsic properties of such objects and, if subsolar mergers are discovered, for testing and constraining the collapsar formation pathway.
Source: arXiv (Cornell University)
Institutions: Columbia University, Johns Hopkins University, Flatiron Institute
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, National Aeronautics and Space Administration, John Templeton Foundation, Johns Hopkins University, National Centre for Supercomputing Applications, Space Telescope Science Institute, Science Foundation Ireland, Ministero degli Affari Esteri e della Cooperazione Internazionale, Office of Advanced Cyberinfrastructure
Awards: G1260521266, G1353381076, G1453181110, G1503004319, Track 4: Advanced CI Coordination Ecosystem: Monitoring and Measurement Services, Physics and Astrophysics of Compact Binaries, G298330452, WoU-MMA: Engine-Powered Transients from Compact Object Birth, G3350504286, G3562386289, G358278991, Track 1: ACCESS Resource Allocations Marketplace and Platform Services (RAMPS), G4010157413, G433322167, G4403015908, Gravitational waves for cosmology, gravity, and quantum mechanics, ACO: An Open CI Ecosystem to Advance Scientific Discovery (OpenCI), Track 3: COre National Ecosystem for CyberinfrasTructure (CONECT), G5367127336, G5464919783, G58316358, MRI: Acquisition of an Advanced Computing Instrument to Integrate Data-Driven Research and Data intensive computing at Johns Hopkins University, G6273510985, Collaborative Research: Understanding Compact Binary Formation With Gravitational Wave Observations, G7271693654, G8108599699, Track 2: Customized Multi-tier Assistance, Training, and Computational Help (MATCH) for End User ACCESS to CI, Collaborative Research: Understanding Compact Binary Formation With Gravitational Wave Observations
OpenAlex ID: W7214080879