Discovery of a Possible Anomalous X-ray Pulsar in the Small Magellanic Cloud

Abstract

We report the serendipitous detection of a previously unreported pulsar from the direction of the Small Magellanic Cloud using data from the CHANDRA X-Ray Observatory. Because of the luminosity of about 1.5x10^35 ergs/s, its near lack of variability for more than 20 years, and its soft spectrum we propose that it is an anomalous X-ray pulsar (AXP). Data from the ROSAT PSPC in conjunction with the CHANDRA data give a period, P, of 5.44 s and a spin down time, Pdot/P, of 11 ky. If this is a correct identification it will be the first extragalactic AXP and the fastest yet discovered.