Neutron stars in a perturbative f(R) gravity model with strong magnetic fields


Cheoun M., DELİDUMAN C., Gungor C., Keles V., Ryu C. Y., Kajino T., ...More

JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS, no.10, 2013 (SCI-Expanded) identifier identifier

Abstract

In Kaluza-Klein electromagnetism it is natural to associate modified gravity with strong electromagnetic fields. Hence, in this paper we investigate the combined effects of a strong magnetic field and perturbative f(R) gravity on the structure of neutron stars. The effect of an interior strong magnetic field of about 10(17-18) G on the equation of state is derived in the context of a quantum hadrodynamics (QHD) equation of state (EoS) including effects of the magnetic pressure and energy along with occupied Landau levels. Adopting a random orientation of interior field domains, we solve the modified spherically symmetric hydrostatic equilibrium equations derived for a gravity model with f(R) = R + alpha R-2. Effects of both the finite magnetic field and the modified gravity are detailed for various values of the magnetic field and the perturbation parameter a along with a discussion of their physical implications. We show that there exists a parameter space of the modified gravity and the magnetic field strength, in which even a soft equation of state can accommodate a large (>2 M-circle dot) maximum neutron star mass.