X-rays from the oxygen-type Wolf-Rayet binary WR30a

S.A.Zhekov (1) and S.L.Skinner (2)

(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.

Reference: Monthly Notices of the Royal Astronomical Society
Status: Manuscript has been accepted

Weblink: http://xxx.lanl.gov/abs/1506.04634


Email: szhekov@astro.bas.bg