Magnetic fields in compact stars and related phenomena

Abstract

Magnetic fields appear at all scales in the Universe, spanning many orders of magnitude in their strength, and intervening in the development of many astrophysical processes. In particular, in compact objects, magnetic fields can reach huge intensities and play a fundamental role in the evolution of the star and its surroundings. In this review, the most relevant ideas about their generation mechanisms and their eects on the composition and evolution of compact stars are summarized. The review highlights the role played by anisotropic pressures, induced by the presence of strong magnetic fields, in the equation of state and in the macroscopic observables of compact objects. Anisotropies demand to solve Einstein equations beyond the spherical
symmetry. In this regard, two models are analyzed, one using a metric in cylindrical coordinates and another one considering a metric, which allows to take into account small deformations of the objects. These results are relevant for the description of magnetized white dwarfs and hypothetical quark and Bose-Einstein condensate stars. Some related astrophysical phenomena, as pulsar kick velocities and jets associated to compact objects, are also addressed as a consequence of the presence of strong magnetic fields.