Speaker
Description
We present a study on the application of a family of high-order Central WENO (CWENO) Finite Difference (FD) schemes to simulate Binary Neutron Star (BNS) mergers, where the initial data configurations are generated with the Lorene library following [1].
The evolution is performed in the framework of the first-order hyperbolic Generalized Harmonic (GH) formulation of the Einstein equations of general relativity introduced in [2], coupled to the relativistic Euler equations for the matter sector. The proposed numerical methods have previously demonstrated their efficiency and robustness when applied to several numerical relativity benchmark problems within the same formulation as detailed in [3]. Preliminary results show the successful simulation of several orbits of the inspiral phase, and in particular of the merger itself thanks to the strong shock-capturing properties of the numerical schemes adopted, opening the way to their use in more realistic astrophysical applications. We emphasize, nevertheless, that in our work we assume a simple ideal-gas Equation of State (EoS), and consequently an important next step includes the generalization to more involved models of the matter part, adding a thermal component and potentially including also the contribution of microphysics and radiation transport effects.
To conclude, the extraction of gravitational waves is currently under investigation and will provide a comprehensive validation of the developed numerical methodology.
References
[1] E. Gourgoulhon, P. Grandclement, K. Taniguchi, J.-A. Marck, and S. Bonazzola, “Quasiequilibrium sequences of synchronized and irrotational binary neutron stars in general relativity: Method and tests,” Physical Review D, vol. 63, no. 6, p. 064 029, 2001.
[2] L. Lindblom, M. A. Scheel, L. E. Kidder, R. Owen, and O. Rinne, “A new generalized harmonic evolution system,” Classical and Quantum Gravity, vol. 23, no. 16, S447, 2006.
[3] S. Muzzolon, M. Dumbser, O. Zanotti, and E. Gaburro, “High order numerical discretizations of the Einstein- Euler equations in the Generalized Harmonic formulation,” Journal of Computational Physics, p. 115 084, 2026, issn: 0021-9991.
Acknowledgements: S. Muzzolon and E. Gaburro gratefully acknowledge the support received from the European Union with the ERC Starting Grant ALcHyMiA (No. 101114995).