Joint posterior distributions of mass–radius (top) and tidal deformability–mass (bottom) for neutron stars under the FOPT (blue) and NPT (red) hypotheses, shown as 68% and 95% credible regions. The left (right) column is for n_L = 25 n₀ (12 n₀). Astrophysical constraints—NICER joint posteriors for PSR J0740+6620 (T. Salmi et al. 2024a), PSR J0030+0451 (S. Vinciguerra et al. 2024), PSR J0437−4715 (D. Choudhury et al. 2024a), and PSR J0614−3329 (L. Mauviard et al. 2025a), together with the GW170817 posterior (B. P. Abbott et al. 2018)—are overlaid for reference.