Special Astrophysics Seminar

Mysterious Magnetars: Maximum Stars

Vikram Soni

Centre for Theoretical Physics, New Delhi

Magnetars are exceptional neutron stars with the highest magnetic fields (10¹⁵ gauss) in the universe, an unusual quasi steady X radiation (10³⁵ ergs/sec) and also produce flares which are some of the brightest events (10⁴⁶ ergs in one fifth of a second) to be recorded. There is no satisfactory model of magnetars.

The talk will cover neutron stars and a new model for the origin of the magnetic fields in which magnetars arise from a high baryon density ( phase transition) magnetized core which forms when they are born. The core magnetic field is initially shielded by the ambient high conductivity plasma. With time the shielding currents dissipate transporting the core field out, first to the crust and then breaking through the crust to the surface of the star. Recent observations provide support for this model which accounts for several properties of magnetars and also enables us to identify new magnetars.The somewhat sudden cessation of quasi steady X ray emission and rising polar magnetic fields is a characteristic of such models.