Effect of the symmetry energy on the secondary component of GW190814 as a neutron star
Abstract
The secondary component of GW190814 with a mass of 2.50-2.67 M⊙ may be the lightest black hole or the heaviest neutron star ever observed in a binary compact object system. To explore the possible equation of state (EOS), which can support such a massive neutron star, we apply the relativistic mean-field model with a density-dependent isovector coupling constant to describe the neutron-star matter. The acceptable EOS should satisfy some constraints: the EOS model can provide a satisfactory description of the nuclei; the maximum mass MTOV is above 2.6 M⊙; the tidal deformability of a canonical 1.4 M⊙ neutron star Λ1.4 should lie in the constrained range from GW170817. In this paper, we find that nuclear symmetry energy and its density dependence play a crucial role in determining the EOS of neutron-star matter. The constraints from the mass of 2.6 M⊙ and the tidal deformability Λ1.4=616−158+273 (based on the assumption that GW190814 is a NS-BH binary) can be satisfied for the slope of symmetry energy L ≤50 MeV. Even including the constraint Λ1.4=190−120+390 from GW170817 which suppresses the EOS stiffness at low density, the possibility that the secondary component of GW190814 is a massive neutron star cannot be excluded in this study.
- Publication:
-
Physical Review C
- Pub Date:
- July 2021
- DOI:
- 10.1103/PhysRevC.104.015802
- arXiv:
- arXiv:2101.05476
- Bibcode:
- 2021PhRvC.104a5802W
- Keywords:
-
- Nuclear Theory;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 8 pages, 6 figures