Signatures of deconfined quark phases in binary neutron star mergers*

We investigate QCD phase transitions in the context of binary neutron star (BNS) mergers. Comparing numerical relativity simulations with equations of state (EOS) that model respectively hadronic matter and a first-order phase transition to quarks, we find that the latter causes an earlier collapse of the merger remnant to a black hole. The phase transition is imprinted on the postmerger gravitational wave (GW) signal duration, amplitude, and peak frequency and does not cause significant deviations from quasi-universal relations for the postmerger GW peak frequency. Hence the postmerger GW peak frequency alone is not sufficient to conclusively exclude or confirm the presence of a phase transition. We also study the impact of the phase transition on dynamical ejecta, remnant accretion disk masses, r-process nucleosynthetic yields, and associated electromagnetic (EM) counterparts. The most robust feature is the non-thermal afterglow caused by the interaction of the fastest component of the dynamical ejecta and the interstellar medium, which is systematically boosted in binaries with phase transition as a consequence of the more violent merger they experience.