CAREER: Next-Generation Microphysics Multiscale Modeling of Neutron Star Mergers

This award supports research at the intersection of gravitational-wave astrophysics, numerical relativity, and plasma and nuclear astrophysics, focused on understanding the fundamental physics of merging neutron stars. These mergers are among the most extreme events in the universe and produce gravitational waves, electromagnetic transients, and heavy elements essential for the chemical evolution of galaxies. With additional binary neutron star detections anticipated from the Advanced LIGO observatories, a major scientific challenge is to connect these multi-messenger observations to the underlying properties of dense matter, magnetic fields, and relativistic plasma dynamics. The research advances national scientific priorities in multi-messenger astrophysics and directly supports the scientific goals of the U.S. gravitational-wave program. The award also contributes to workforce development through the training of graduate and undergraduate researchers in computational science, relativistic astrophysics, and data-driven scientific modeling. Educational and outreach activities include public lectures, collaborations with local high schools, development of new graduate coursework in relativistic hydrodynamics and magnetohydrodynamics, and the organization of Caltech Relativistic Astrophysics Summer Schools to broaden participation in STEM and increase public engagement with modern physics. The research develops next-generation numerical relativity simulations of binary neutron star mergers that incorporate realistic multi-scale microphysics in dynamical spacetime evolutions. The project focuses on modeling the impact of dense-matter physics, weak interactions, magnetic-field amplification, relativistic superfluidity, neutron star crust dynamics, and exotic strangeness-bearing phases on gravitational-wave and electromagnetic observables. New computational infrastructure will be developed to enable simulations of these regimes, addressing major gaps in current numerical relativity capabilities. These simulations will be used to study signatures of neutron star crust physics during inspiral, chemical equilibration processes during merger and post-merger evolution, and dynamo-driven magnetic-field amplification relevant for long-lived neutron star remnants. The results are expected to improve the interpretation of gravitational-wave observations and multi-messenger counterparts, while advancing constraints on the neutron star dense-matter equation of state and the physics of strongly interacting matter under extreme conditions. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria. NSF Award ID: 2541792 | Program: 01003031DB NSF RESEARCH & RELATED ACTIVIT,01002930DB NSF RESEARCH & RELATED ACTIVIT,01002627DB NSF RESEARCH & RELATED ACTIVIT | Principal Investigator: Elias Most | Institution: California Institute of Technology, PASADENA, CA | Award Amount: $300,000 View on NSF Award Search: https://www.nsf.gov/awardsearch/show-award/?AWD_ID=2541792 View on Research.gov: https://www.research.gov/awardapi-service/v1/awards/2541792.html