@article {23902,
	title = {Optical Spectroscopy of 20 Be/X-ray Binaries in the Small Magellanic Cloud},
	volume = {707},
	year = {2009},
	month = {2009/12/1},
	pages = {1080 - 1097},
	abstract = {We present a large sample (20 in total) of optical spectra of Small Magellanic Cloud (SMC) High-Mass X-ray Binaries obtained with the 2dF spectrograph at the Anglo-Australian Telescope. All of these sources are found to be Be/X-ray binaries (Be-XRBs), while for five sources we present original classifications. Several statistical tests on this expanded sample support previous findings for similar spectral-type distributions of Be-XRBs and Be field stars in the SMC, and of Be-XRBs in the Large Magellanic Cloud and the Milky Way, although this could be the result of small samples. On the other hand, we find that Be-XRBs follow a different distribution than Be stars in the Galaxy, also in agreement with previous studies. In addition, we find similar Be spectral-type distributions between the Magellanic Clouds samples. These results reinforce the relation between the orbital period and the equivalent width of the Hα line that holds for Be-XRBs. SMC Be stars have larger Hα equivalent widths when compared to Be-XRBs, supporting the notion of circumstellar disk truncation by the compact object.},
	keywords = {Astrophysics - Astrophysics of Galaxies, Astrophysics - High Energy Astrophysical Phenomena, Be, galaxies: individual: Galaxy, Magellanic Clouds, stars: emission-line, X-rays: binaries},
	isbn = {0004-637X},
	url = {https://ui.adsabs.harvard.edu/abs/2009ApJ...707.1080A},
	author = {Antoniou, V. and Hatzidimitriou, D. and Zezas, A. and Reig, P.}
}
