Hadron–quark phase transition in the context of GW190814
Ishfaq A Rather, A A Usmani, S K Patra
Abstract
Abstract The properties of neutron stars are calculated for hadronic matter within the density-dependent relativistic mean-field model (DD-RMF). The phase transition to quark matter is studied and the hybrid star matter properties are systematically calculated using the vector-enhanced bag model. The maximum mass of a neutron star with DD-LZ1 and DD-RMF parameter sets is found to be around 2.55 M ⊙ for the pure hadronic phase and around 2 M ⊙ for the hadron–quark mixed phase using both Gibbs and Maxwell construction (MC). The variation in tidal deformability for the hybrid equation of state (EoS) at 1.4 M ⊙ depends upon the construction of the phase transition. While it remains unchanged with MC, but decreases with the increasing neutron star mass for Gibbs construction. The pure hadron matter EoS satisfies the maximum mass constraint from recently observed GW190814 data, implying a stiff neutron star EoS. The phase transition to quark matter satisfies the maximum mass and radius constraints from the GW170817 event. Therefore, we cannot exclude the possibility of the secondary object in GW190814 as a neutron star with a phase transition to quark matter that satisfies the 2 M ⊙ maximum mass limit.