\begin{center}{\Large\bf 
X-rays from the oxygen-type Wolf-Rayet binary  WR30a}\end{center} 

\centerline{\bf S.A.Zhekov (1) and S.L.Skinner (2)
}{\footnotesize (1) Institute of Astronomy and National Astronomical observatory, Sofia, Bulgaria
(2) CASA, University of Colorado, Boulder, USA
}
 
We present an analysis of XMM-Newton X-ray data of WR30a (WO+O),
a close massive binary that harbours an oxygen-rich Wolf-Rayet star.
Its spectrum is characterized by the presence of two well-separated
broad peaks, or `bumps', one peaking at energies between 1 and 2 keV
and the other between 5 and 7 keV. A two-component model is required
to match the observed spectrum. The higher energy spectral peak  is
considerably more absorbed and dominates the X-ray luminosity.
For the currently accepted distance of 7.77 kpc, the X-ray
luminosity of WR30a is L_X > 10^{34} erg s^{-1}, making it one of the
most X-ray luminous WR+O binary amongst those in the Galaxy with
orbital periods less than ~20 d. The X-ray spectrum  can be acceptably
fitted using either thermal or nonthermal models, so the X-ray
production mechanism is yet unclear.

{\bf Reference: Monthly Notices of the Royal Astronomical Society} \\{\it Status:} Manuscript has been accepted
 \\ {\it Comments:} 

{\it On the web at:} {\tt http://xxx.lanl.gov/abs/1506.04634} 

{\it Preprints from:} {\tt  szhekov@astro.bas.bg} 
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