A strongly magnetized strange star model for soft gamma-ray repeaters

Abstract

Soft γ-ray repeaters (SGRs) have been currently argued as super-strongly magnetized neutron stars (magnetars) with magnetic fields with a few 1014 G. Here we propose an alternate model, in which SGRs are young strange stars with superconducting cores and with poloidal magnetic fields of normal radio pulsars. For SGR 1806 - 20, its magnetic field is taken to be ∼3 × 1013 G in order to match the stellar characteristic timescale and the age of the surrounding supernova remnant (SNR) associated with this burster. The movement of the magnetic flux tubes in these strange stars not only leads to crustal cracking of the stars, giving rise to deconfinement of crustal matter to strange matter, but also to movement of internal magnetic toruses together with the flux tubes. The former process will result in bursting and quiescent emission and the latter process will produce quasi-steady relativistic winds which will power the surrounding SNR. The observed persistent X-ray luminosity, bursting behavior and inferred wind luminosity of SGRs can be explained in this model. The possible relation between the sources of SGRs, anomalous X-ray pulsars and gamma-ray bursts is discussed. © 2002 Elsevier Science B.V. All rights reserved.