• DOI:10.1017/S1743921317002757
• Corpus ID: 119471082

Hα imaging for BeXRBs in the Small Magellanic Cloud

@article{Maravelias2016HIF,
  title={H$\alpha$ imaging for BeXRBs in the Small Magellanic Cloud},
  author={Grigoris Maravelias and Andreas Zezas and Vallia Antoniou and Despina Hatzidimitriou and Frank Haberl},
  journal={Proceedings of the International Astronomical Union},
  year={2016},
  volume={12},
  pages={373 - 375}
}

• G. Maravelias, A. Zezas, +2 authors F. Haberl
• Published 1 November 2016
• Physics
• Proceedings of the International Astronomical Union

Abstract The Small Magellanic Cloud (SMC) hosts a large number of high-mass X-ray binaries, and in particular of Be/X-ray Binaries (BeXRBs; neutron stars orbiting OBe-type stars), offering a unique laboratory to address the effect of metalicity. One key property of their optical companion is Hα in emission, which makes them bright sources when observed through a narrow-band Hα filter. We performed a survey of the SMC Bar and Wing regions using wide-field cameras (WFI@MPG/ESO and MOSAIC@CTIO/Blanco) in order to identify the counterparts of the sources detected in our XMM-Newton survey of the same area. We obtained broad-band R and narrow-band Hα photometry, and identified ~10000 Hα emission sources down to a sensitivity limit of 18.7 mag (equivalent to ~B8 type Main Sequence stars). We find the fraction of OBe/OB stars to be 13% down to this limit, and by investigating this fraction as a function of the brightness of the stars we deduce that Hα excess peaks at the O9-B2 spectral range. Using the most up-to-date numbers of SMC BeXRBs we find their fraction over their parent population to be ~0.002 − 0.025 BeXRBs/OBe, a direct measurement of their formation rate.