Elias Most, "Neutron star mergers: Fast ejecta, magnetic fields and dense matter"
Gravitational wave events involving very massive neutron stars, such as GW190425, have just started to be detected. Although typically classified as binary neutron star mergers, the observed gravitational-wave signal is usually not able to clearly establish a neutron-star nature of the massive primary object in the system. Thus, a black hole--neutron star system cannot be fully ruled out by the gravitational wave detection alone. In the first part of this talk, I will show how early fast ejecta -- only produced in binary neutron star mergers -- can potentially resolve this question and shed light on the nature of the binary system. Focusing on the post-merger evolution of these systems, I will comment on the evolution of magnetic fields and the potential of jet launching from near-equal mass mergers.
In the second part of the talk, we will go beyond the presently observed inspiral phase of a binary neutron star coalescence, and focus on post-merger observables. I will discuss how properties of dense nuclear matter, such as the nuclearsymmetry energy, and out-of-(weak-) equilibrium effects are affecting the post-mergergravitational wave signal. Understanding these various contributions to the post-merger evolution will be key to interpreting next-generation gravitational wave detections.
For additional information, please see https://gravity.princeton.edu/people/elias-most