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arXiv · 1608.03897

Chandra and Swift X-ray Observations of the X-ray Pulsar SMC X-2 During the Outburst of 2015

K. L. Li·C. -P Hu·L. C. C. Lin·Albert K. H. Kong
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Abstract

We report the Chandra/HRC-S and Swift/XRT observations for the 2015 outburst of the high-mass X-ray binary (HMXB) pulsar in the Small Magellanic Cloud, SMC X-2. While previous studies suggested that either an O star or a Be star in the field is the high-mass companion of SMC X-2, our Chandra/HRC-S image unambiguously confirms the O-type star as the true optical counterpart. Using the Swift/XRT observations, we extracted accurate orbital parameters of the pulsar binary through a time of arrivals (TOAs) analysis. In addition, there were two X-ray dips near the inferior conjunction, which are possibly caused by eclipses or an ionized high-density shadow wind near the companion's surface. Finally, we propose that an outflow driven by the radiation pressure from day ~10 played an important role in the X-ray/optical evolution of the outburst.

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K. L. Li, C. -P Hu, L. C. C. Lin, Albert K. H. Kong. 2016-08-12. Chandra and Swift X-ray Observations of the X-ray Pulsar SMC X-2 During the Outburst of 2015. https://doi.org/10.3847/0004-637x/828/2/74

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