Thermal Evolution of Magnetars under f(R, T) Gravity

TL;DR

This paper investigates how modified $f(R, T)$ gravity influences the thermal evolution and emission properties of neutron stars, including magnetars, by comparing predictions with observations and standard gravity models.

Contribution

It introduces the application of $f(R, T)$ gravity to neutron star cooling, showing improved agreement with observations over general relativity for certain equations of state.

Findings

$f(R, T)$ gravity better matches observed surface temperatures.

Magnetic fields influence neutron star cooling but are consistent across gravity models.

Neutrino luminosities are predicted under various conditions.

Abstract

The present study explores the thermal evolution and emission properties of neutron stars within the framework of modified $f(R, T)$ gravity by solving the coupled energy-balance and heat-transport equations. We compute stellar mass and pressure profiles by solving the Tolman-Oppenheimer-Volkoff equations in both Einstein gravity and modified gravity, employing the APR, FPS, and SLy equations of state, with and without the strong magnetic field. Using these profiles, we assess the red-shifted surface temperature, $T_s^{\infty}$, as well as the photon and neutrino luminosities for each equation of state. We further examine the effects of the magnetic field, the choice of equation of state, and the underlying gravity theory framework on the cooling of neutron stars, particularly those of magnetized neutron stars or magnetars. Our results indicate that $f(R, T)$ gravity, particularly for the APR and SLy equations of state, exhibits improved agreement with the observed $T_s^{\infty}$ and photon luminosities than standard general relativity, regardless of magnetic-field strength. Moreover, it predicts the neutrino luminosities under both gravity models, all the chosen equations of state, and magnetic field configurations.