Speaker
Description
Binary neutron star mergers serve as unique laboratories for studying dense matter and gravity, from finite-size interactions during the late inspiral to the complex dynamics of the post-merger phase. In this talk, I will first discuss the dynamical tides of neutron stars, investigating the roles of compositional stratification, solid components, and possible QCD phase transitions. I examine mode excitations and their imprints in gravitational wave phase shifts, the shattering of crusts, and the associated energy budget available to power electromagnetic precursors. The massive neutron star formed after the merger is heated to several tens of MeV, exhibits strong differential rotation, and undergoes violent oscillations. Studying the system's hydrodynamics and gravitational radiation in detail is essential for placing robust constraints on the hot equation of state. We analyze the post-merger properties with respect to the unknown thermal heating efficiency and the possible development of hydrodynamical instabilities, such as convective and one-armed modes, which provide insight into the thermal and rotational structure. Decoding the equation of state is complicated by uncertainties in the underlying theory of gravity; therefore, it is important to explore the gravity dependence of the entire process. Using massive scalar–tensor gravity as an example, I compare scalar-field effects with tidal signatures in the inspiral and assess their impact on the post-merger waveform. I then highlight the necessity of keeping the matter–gravity degeneracy in mind when probing fundamental physics.
| Session Selection | Astronomy and Astrophysics |
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