An X‐Ray Investigation of the NGC 346 Field in the Small Magellanic Cloud. III.XMM‐NewtonData

We present new XMM-Newton results on the field around the NGC346 star clusterin the SMC. This continues and extends previously published work on Chandraobservations of the same field. The two XMM-Newton observations were obtained,respectively, six months before and six months after the previously publishedChandra data. Of the 51 X-ray sources detected with XMM-Newton, 29 were alreadydetected with Chandra. Comparing the properties of these X-ray sources in eachof our three datasets has enabled us to investigate their variability on timesscales of a year. Changes in the flux levels and/or spectral properties wereobserved for 21 of these sources. In addition, we discovered long-termvariations in the X-ray properties of the peculiar system HD5980, a luminousblue variable star, that is likely to be a colliding wind binary system, whichdisplayed the largest luminosity during the first XMM-Newton observation.