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Discovery of Optical Periods for IGR J00569-7226

ATel #5557; P. C. Schmidtke, A. P. Cowley (Arizona State University)
on 6 Nov 2013; 20:05 UT
Credential Certification: Paul Schmidtke (Paul.Schmidtke@asu.edu)

Subjects: Optical, X-ray, Binary

Referred to by ATel #: 5631, 5662

A new bright SMC X-ray source has recently been discovered by Coe et al. (ATel #5547) using INTEGRAL data. From Swift observations, the source's position has been refined by Kennea (ATel #5553) to be RA=00:57:02.34 and Dec=-72:25:55.34. The optical counterpart lies in OGLE-II field SMC_SC7, and we identify it with star 266703. The I light curve of this star varies between I=15.85 and 15.6 with a long-period modulation of 299 days and decreasing amplitude during four seasons. After flattening data from the first season, periodogram analysis shows two significant periods: P=17.2 d (which might be the orbital period) or its alias P=0.94 d (which would suggest non-radial pulsations of the Be star). The variations are nearly sinusoidal on each period, with a full amplitude ~0.02 mag. This photometric behavior is similar to that seen in many other Be/X-ray binaries.