Impact of quark deconfinement in neutron star mergers and hybrid star mergers

Understand

We describe an unambiguous gravitational-wave signature to identify the occurrence of a strong phase transition from hadronic matter to deconfined quark matter in neutron star mergers.

• Such a phase transition leads to a strong softening of the equation of state and hence to more compact merger remnants compared to purely hadronic models.
• If a phase transition takes place during merging, this results in a characteristic increase of the dominant postmerger gravitational-wave frequency relative to the tidal deformability characterizing the inspiral phase.
• By comparing results from different purely hadronic and hybrid models we show that a strong phase transition can be identified from a single, simultaneous measurement of pre- and postmerger gravitational waves.