Predicted values of braking indexes and second frequency derivatives for magnetars

To date, the observational determination of braking indexes of magnetars is still an open question due to the lack of long‐term radio emission and strong timing noise. Based on the assumption that the real ages of magnetars are the ages of their host supernova remnants (SNRs), expanding diffuse gaseous nebulae resulting from explosions of massive stars, we obtain the sizes of the braking index n for 11 magnetar candidates with SNRs. According to our calculations, the magnetar braking indexes will be constrained within the range of about 1–40, assuming the measurements of SNRs are reliable. We also investigate the frequency parameters of magnetars with associated SNRs, and estimate possible wind luminosities for magnetars with n < 3 and magnetic field decay rates for magnetars with n > 3. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)