Black Hole - Neutron Star mergers: Theoretical Modeling, Numerical Simulations, and Data Interpretation

• Applicant: Professor Dr. Tim Dietrich
• Subject Area: Astrophysics and Astronomy
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 504148597

The first direct detection of gravitational waves inaugurated a new era in astronomy. Since then numerous compact binary mergers have been detected, among them gravitational waves emitted from the collision of a black hole with a neutron star. Such black hole - neutron star systems can reveal information about the state of matter at supranuclear densities or allow for a more precise measurement of the Hubble constant. Because of this, it is essential to enable an accurate cross-correlation between theoretical models and observational data. This requires a reliable theoretical description of the black hole - neutron star coalescence, the emitted gravitational-wave signal, and potential electromagnetic counterparts. Unfortunately, the number of available numerical-relativity simulations for black hole - neutron star systems is small and the corresponding waveform models for this class of systems are in their infancy. Within this research project, we plan to fill these gaps. For this purpose, we will extend the code infrastructure of the pseudo-spectral code Elliptica to allow the construction of accurate black hole - neutron star initial data. These data will be evolved with the BAM code and our new simulation results will be the fundament for the development of new gravitational-wave models and phenomenological estimates of the disk mass and ejecta outflows. We plan to make all our results and codes publicly available.

• DFG Programme: Research Grants
• International Connection: USA
• Cooperation Partners: Alireza Rashti; Professor Dr. Wolfgang Tichy