Yael Naze, Gregor Rauw, Damien Hutsemekers
Aims: The X-ray emission of massive stars has been studied when these objects
are in their main-sequence phase, as well as in their Wolf-Rayet phase.
However, the X-ray properties of the transitional Luminous Blue Variable (LBV)
phase remain unknown. Methods: Using a dedicated but limited XMM survey as well
as archival XMM and Chandra observations, we performed the first X-ray survey
of LBVs: about half of the known LBVs or candidate LBVs are studied. Results:
Apart from the well known X-ray sources eta Car and Cyg OB2 #12, four
additional LBVs are detected in this survey, though some doubt remains on the
association with the X-ray source for two of these. For the other LBVs, upper
limits on the flux were derived, down to $\log[L_{\rm X}/L_{\rm BOL}]-9.4$ for
PCyg. This variety in the strength of the X-ray emission is discussed, with
particular emphasis on the potential influence of binarity.
View original:
http://arxiv.org/abs/1111.6375
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