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-second X-raypulsar CXOU J010043.1-721134 from a series of observations using the ChandraX-ray Observatory. We find a spin period in 2004 January of 8.020392pm0.9seconds. Comparison of this to 2001 Chandra observations implies a periodderivative dot{P} = (1.88 pm 0.08) times 10^{-11} s s^{-1}, leading to aninferred dipole surface magnetic field of 3.9 times 10^{14} G. The spectrum iswell fit to an absorbed blackbody of temperature kT = 0.38pm0.02 keV with apower law tail of photon index Gamma = 2.0pm0.6. We find that the source has anunabsorbed X-ray flux (0.5-10 keV) of 4(+2-1) times 10^{-13} erg cm^{-2} s^{-1}and a corresponding X-ray luminosity of ~2 times 10^{35} erg s^{-1} for adistance of 60 kpc. These properties support classification of CXOUJ010043.1-721134 as the seventh confirmed anomalous X-ray pulsar,the eleventhconfirmed magnetar, and the first magnetar to be identified in the SmallMagellanic Cloud.Comment: 5 pages, plus 1 embedded eps figure. Refined coordinates of source, including typo in declination. ApJ Letters, in pres