Do magnetars glitch? Timing irregularities in anomalous X-ray pulsars

We examine the timing history of several anomalous X-ray pulsars (AXPs), and find that they exhibit spin-down irregularities that are statistically similar to those of radio pulsars. We propose that these irregularities are simply glitches like those of radio pulsars, and fit glitching spin-down solutions to the data available for 1E 2259+586, 1E 1048.1-5937 and 4U 0142+61. The inferred magnitude of the glitches (Delta Omega) is comparable to that exhibited in radio pulsar glitching. With these results, we argue that the three AXPs that we have studied are isolated neutron stars spinning down by magnetic dipole radiation and powered by a combination of cooling, magnetic field decay and magnetospheric particle bombardment.