Isovector Effects in Neutron Stars, Radii and the GW170817 Constraint

T.F. Motta , A.M. Kalaitzis , S. Antić , P.A.M. Guichon (1) , J.R. Stone , A.W. Thomas

1 IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers

An isovector–scalar meson is incorporated self-consistently into the quark–meson coupling description of nuclear matter, and its most prominent effects on the structure of neutron stars are investigated. The recent measurement of GW170817 is used to constrain the strength of the isovector–scalar channel. With the imminent measurements of the neutron star radii in the NICER mission, it is particularly notable that the inclusion of the isovector–scalar force has a significant impact. Indeed, the effect of this interaction on the neutron star radii and masses is larger than the uncertainties introduced by variations in the parameters of symmetric nuclear matter at saturation, namely the density, binding energy per nucleon, and the symmetry energy. In addition, as the analysis of GW170817 has provided constraints on the binary tidal deformability of merging neutron stars, the predictions for this parameter within the quark–meson coupling model are explored, as well as the moment of inertia and the quadrupole moment of slowly rotating neutron stars.

Mots clés: Nuclear Matter; Tidal Deformability; Neutron Stars; GW170817; Quark Meson Coupling; equation of state; gravitational waves; stars: neutron; neutron star: rotation; interaction: effect; energy: symmetry; nuclear matter; binding energy; gravitational radiation: direct detection; gravitational radiation: emission; isovector; star: density; nucleon; binary: coalescence; meson

Domaines: Physique Nucléaire Théorique [nucl-th]; Astrophysique [astro-ph]

T.F. Motta, A.M. Kalaitzis, S. Antić, P.A.M. Guichon, J.R. Stone, et al.. Isovector Effects in Neutron Stars, Radii and the GW170817 Constraint. Astrophys.J., 2019, 878 (2), pp.159. ⟨10.3847/1538-4357/ab218e⟩. ⟨hal-02123370⟩