X-Ray Timing, Spectroscopy, and Photometry of the Anomalous X-Ray Pulsar Candidate CXOU J010043.1–721134

We present new X-ray timing and spectral results on the 8.0 s X-ray pulsar CXOU J010043.1-721134 from a series of observations using the Chandra X-Ray Observatory. We found a spin period in 2004 January of 8.020392 ± 0.000009 s. A comparison of this to the 2001 Chandra observations implies a period derivative = (1.88 ± 0.08) × 10-11 s s-1, leading to an inferred dipole surface magnetic field of 3.9 × 1014 G. The spectrum is well fit to an absorbed blackbody of temperature kT = 0.38 ± 0.02 keV with a power-law tail of photon index Γ = 2.0 ± 0.6. We find that the source has an unabsorbed X-ray flux (0.5-10 keV) of 4 × 10-13 ergs cm-2 s-1 and a corresponding X-ray luminosity of ~2 × 1035 ergs s-1 for a distance of 60 kpc. These properties support the classification of CXOU J010043.1-721134 as the seventh confirmed anomalous X-ray pulsar, the eleventh confirmed magnetar, and the first magnetar to be identified in the Small Magellanic Cloud.