2002ApJ...568..226M

We report on high time and spatial resolution observations of the supernova remnant (SNR) 3C 58 using the High Resolution Camera (HRC) on the Chandra X-Ray Observatory. These data show a pointlike central source from which we detect 65.68 ms pulsations at 6.7 σ significance. We interpret these pulsations as corresponding to a young rotation-powered pulsar, PSR J0205+6449, that is associated with and powers SNR 3C 58. Analysis of archival Rossi X-Ray Timing Explorer (RXTE) data from 3 years earlier confirms these pulsations and allows us to determine a spin-down rate of P{dot}=1.93x10^–13s.s^–1. Assuming a magnetic dipole model for PSR J0205+6449, we infer a surface magnetic field of 3.6x10¹² G. The historical age for the pulsar (based on its identification with SN 1181) is 820 yr. Taken with the observed period and spin-down rate, we derive an initial spin period of ∼60 ms.