Speaker
Zhi Fu Gao
(Xinjiang Astronomical Observatory, CAS, 150, Science 1-Street, Urumqi Xinjiang, 830011,China)
Description
From observations, more than one-third of the detected candidate magnetars with magnetic field strengths in excess of the quantum critical value are associated with the known supernova remnants (SNRs), suggestive of an origin in massive star explosions. To date, the observational determination of braking indices of magnetars is still an open question due to strong timing noise and lake of long-term radio emission (expect for 3 candidates). Based on the assumption that the real ages of magnetars is the ages of their associated SNRs, we deduce a general formula for magnetar braking indices n, and compute the values of n for 10 candidates with SNRs. According to our model, the magnetar braking indices n different from three expected for pure magnetic-dipole radiation model will be in the range of 10^{-1}-10^2 assuming the measurements of SNRs are reliable. We also investigate the relationship between the characteristic ages of magnetars and the ages of their SNRs, and explain why some magnetars associated with SNRs look older than their real ages, whereas other magnetars associated with SNRs appear younger than they are. It is important that our method can also be applied to constrain braking indices of common neutron stars by their associated SNRs in spite of the observational errors on the measurements of SNRs.
Primary author
Zhi Fu Gao
(Xinjiang Astronomical Observatory, CAS, 150, Science 1-Street, Urumqi Xinjiang, 830011,China)
Co-author
Na Wang
(Xinjiang Astronomical Observatory, CAS, 150, Science 1-Street, Urumqi Xinjiang, 830011,China)
