Effects of the symmetry energy slope on magnetized neutron stars

TL;DR

This work investigates how the nuclear symmetry energy slope $L$ shapes the properties of magnetized neutron stars within a chaotic magnetic field framework. By employing an extended QHD model with the L3$\omega\rho$ parametrization and a magnetic-field prescription that preserves isotropy, the authors compute EOSs and derive macroscopic observables such as masses, radii, redshifts, tidal deformabilities $\Lambda$, and $f$-mode GW frequencies. The study finds that while the redshift is weakly affected by magnetization, $\Lambda$ is highly sensitive to both $L$ and the magnetic field, and the $f$-mode frequencies exhibit notable dependence on $L$ for low-mass stars and on the field across the mass range, with universal relations modulated by $L$ and field strength. These results imply that upcoming electromagnetic and gravitational-wave observations can help discriminate magnetized neutron-star interiors and constrain the slope of the symmetry energy.

Abstract

In this work, we study the effect of the symmetry slope on the observables of weakly and strongly magnetized neutron stars within the chaotic magnetic field approximation. We investigate the impact of the symmetry energy slope in the equation of state, as well as on the observables of neutron stars, by calculating their masses, radii, redshifts, tidal deformabilities, and fundamental-mode gravitational-wave frequencies.

Figures (4)

• Figure 1: (left) EOS and (right) mass-radius relation for magnetized matter. Solid lines indicate weakly-magnetized neutron stars, and dotted lines indicate strongly-magnetized ones.
• Figure 2: (Top-left) Redshift and (Top-right) dimensionless tidal parameter. (Bottom) Zoom-in focusing on masses between 1.3 and 1.6 solar masses. Solid lines indicate weakly-magnetized neutron stars, and dotted lines indicate strongly-magnetized ones.
• Figure 3: left) Frequency of the fundamental mode (right) damping time. Solid lines indicate weakly-magnetized neutron stars, and dotted lines indicate strongly-magnetized ones
• Figure 4: The frequency of the fundamental mode is plotted in the upper panel as a function of the square root of the average density for the different EoSs. Solid lines indicate weakly-magnetized neutron stars, and dotted lines indicate strongly-magnetized ones