Gravity seminar - Debarati Chatterjee Seminar

 

Neutron stars are dense compact objects, observable as pulsars by virtue of their strong magnetic fields. Further, X-ray Dim Isolated Neutron Stars (XDINSs) and Rotating RAdio Transients (RRATs) have been reported to have even higher fields. Observations of Soft Gamma-ray Repeaters (SGRs) and Anomalous X-ray Pulsars (AXPs) suggest the existence of magnetars, or neutron stars with ultrastrong magnetic fields. On the other hand, to explain observations of overluminous Type I Supernovae, strongly magnetised super-Chandrasekhar mass white dwarfs have been proposed as their progenitors. Presence of such strong magnetic fields can affect the structure of compact stars in two ways: macrophysically, by breaking the spherical symmetry of the star, and microphysically, due to energy quantisation of the constituent charged particles in the field. We present a self-consistent formalism for modeling the macroscopic structure of a strongly magnetised compact object (neutron star or white dwarf), starting from its microscopic Lagrangian. Using this prescription, we construct equilibrium configurations of such objects, simultaneously incorporating effects of magnetic field on the Equation of State, general relativity as well as anisotropy of the energy-momentum tensor due to the electromagnetic field. We draw important conclusions about strongly magnetised compact objects by confronting our theoretical models with observations and compare our results with those existing in the literature.