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

Abstract

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 P˙=(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⁺²_-1×10^-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.