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ATEL # 1529; F. Haberl, P.Eger (Max-Planck-Institut fuer extraterrestrische Physik, MPE)
on 16 May 2008; 9:01 UT
Password Certification: Frank Haberl (firstname.lastname@example.org)
Subjects: X-ray, AGN, Neutron Stars, Pulsars
We report the detection of a point source designated XMMU J005527.6-721059 in an archival XMM-Newton observation in the direction of the SMC from March 2002. The position (see table below) is consistent with the Chandra source CXOU J005527.9-721058 that has been proposed as a Be/X-ray binary pulsar (Edge et al. 2004, ATEL #217; Edge et al. 2004, MNRAS 353,1286) with a pulse period of (34.08 +- 0.03) s (98.5% confidence). Although the source was more than a factor of two brighter during the two times longer XMM-Newton observation, we were not able to confirm this period. Moreover, the EPIC X-ray spectra are well represented by an absorbed powerlaw with a column density (1.6 +- 0.07)E21 cm-2, a photon index 1.65 +- 0.14 and an unabsorbed flux of (5.95 +- 0.43)E-13 erg cm**-2 s**-1. The powerlaw is steeper than observed with EPIC from any other Be/X-ray binary in the SMC (typically below 1.2), suggesting XMMU J005527.6-721059 more likely to be a background AGN.
|Position (J2000)||Error||distance to Be star|