Effects of nucleon-nucleon short-range correlation and symmetry energy on the evolution of newly born magnetars

TL;DR

This paper investigates how nuclear matter properties, especially short-range correlations and symmetry energy, influence magnetar evolution and their role in powering superluminous supernovae, revealing significant effects on luminosity and magnetic inclination.

Contribution

It introduces a detailed model incorporating nuclear matter effects into magnetar evolution, highlighting their impact on supernova luminosity and gravitational wave emission.

Findings

Short-range correlations weaken bulk viscosity damping, reducing gravitational wave peak luminosity.

Nucleon-nucleon correlations increase supernova thermal luminosity.

Stiffer symmetry energy enhances magnetic inclination growth and gravitational wave signals.

Abstract

Millisecond magnetars are widely suggested as the central engines powering hydrogen-poor superluminous supernovae (SLSNe). These magnetars primarily lose huge rotational energy through gravitational wave radiation (GWR) and magnetic dipole radiation (MDR), with MDR serving as an energy source for SLSNe. We study the evolution of the magnetar spin, magnetic inclination angle, and the resulting thermal radiative luminosity of the SLSNe, where the impacts of the nucleon-nucleon short-range correlation, the mass and initial spin of the magnetar, and the density-dependent symmetry energy of the dense nuclear matter on the evolution are discussed. The relativistic mean-field theory is employed to calculate the nuclear matter properties, and we particularly concentrate on the time- and space-dependent bulk viscosity which is crucial for the magnetic inclination angle evolution. It is found that the nucleon-nucleon short-range correlation weakens the damping of bulk viscosity of dense matter and therefore inhibits the growth of magnetic inclination angle, and it reduces the MDR (GWR) peak luminosity of a canonical magnetar by several times while it raises the peak thermal radiation luminosity of SLSNe by several times. For magnetars with nonrotating mass obviously lower than the $ 1.4 M_\odot$ with slow initial rotation, the magnetic inclination angle is more likely to evolve towards 0 degrees quickly, and these magnetars are not suitable as the central engine for SLSNe. Within the "family" of FSUGarnet interaction, a stiffer symmetry energy gives a lower threshold of direct Urca process and hence gives a much larger bulk viscosity coefficient, and thus it promotes the growth of the magnetic inclination angle and the GWR for canonical stars but reduces the peak brightness of SLSNe significantly.