Profile and cooling rate of non-rotating magnetars using strange quark matter equation of states

Abstract

Various astrophysical objects like Neutron Stars, Magnetars, Blackholes, etc. have been extensively studied in the last few decades in order to predict and analyze observations pertaining to such compact objects. Despite of multiple attempts, the exact nature of the matter located inside the core of the above compact objects is still an open problem in Astrophysics. In this work, we attempt to find the profile of spherically symmetric non-rotating Neutron Stars by assuming that the core of the Neutron Star is made up of strange quark matter. The calculation has also been carried out with a core consisting of non-strange quark matter for comparison. We also include the impact of the magnetic field on the profile of the Neutron Stars employing a modified Tolmann-Oppenheimer-Volkoff system of equations. Using the profile thus obtained, the Neutron Star cooling rate with time and as a function of the radius has also been calculated with and without magnetic field effects using NSCool code. Two approaches namely; a fixed value of the magnetic field and a more realistic distance-dependent magnetic field obtained by using a fitted eight-order polynomial have been used in the current calculation. Finally, we plot the Neutron cooling rate with and without magnetic fields by using the different equations of states (EOS) along with corresponding observed data for a few neutron Stars.