Assessing the joint effect of temperature and magnetic field on the neutron star equation of state

TL;DR

This paper investigates how strong magnetic fields and finite temperature influence the equation of state of neutron star matter, revealing that temperature has a more significant impact than magnetic fields, but both affect proton fractions at low densities.

Contribution

The study provides a detailed analysis of combined magnetic field and temperature effects on neutron star matter within relativistic mean field models, highlighting their impact on proton fractions.

Findings

Finite temperature has a stronger effect on the EoS than magnetic fields.

Magnetic fields and temperature increase proton fractions at low densities.

Magnetic field effects on proton fractions are non-negligible up to 10 MeV temperatures.

Abstract

In this work, we study the effect of strong magnetic fields on the equation of state (EoS) of warm, homogeneous, Neutron Star (NS) matter in beta equilibrium. NS matter is described within a relativistic mean field (RMF) approximation, including both models with non-linear meson terms or with density dependent nucleon-meson couplings. We first study the effect of magnetic fields and finite temperature on the EoS separately, finding that the effect of the latter to be significantly stronger than the one of the former. We then study the combined effect of magnetic fields and temperature on the internal composition. We show how both factors cause an increase in the proton fraction at low density and that, as long as the temperatures considered are not higher than 10 MeV, the effect of the magnetic field on the proton fraction is not small enough to be neglected.