The First Glitch in a Central Compact Object Pulsar: 1E 1207.4-5209

Since its discovery as a pulsar in 2000, the central compact object (CCO) 1E 1207.4-5209 in the supernova remnant PKS 1209-51/52 had been a stable 0.424 s rotator with an extremely small spin-down rate and weak ({B}_s≈ 9× {10}¹⁰ G) surface dipole magnetic field. In 2016 we observed a glitch from 1E 1207.4-5209 of at least {{Δ }}f/f=(2.8+/- 0.4)× {10}^-9, which is typical in size for the general pulsar population. However, glitch activity is closely correlated with spin-down rate \dot{f}, and pulsars with \dot{f} as small as that of 1E 1207.4-5209 are never seen to glitch. Unlike in glitches of ordinary pulsars, there may have been a large increase in \dot{f} as well. The thermal X-ray spectrum of 1E 1207.4-5209, with its unique cyclotron absorption lines that measure the surface magnetic field strength, did not show any measurable change after the glitch, which rules out a major disruption in the dipole field as a cause or result of the glitch. A leading theory of the origin and evolution of CCOs, involving the prompt burial of the magnetic field by the fallback of supernova ejecta, might hold the explanation for the glitch.