X-ray analysis of the colliding wind binary FO15

We combine and analyze ten XMM-Newton X-ray observations of the FO15 hot massive (O5V((f))+O9.5V) binary system. EPIC spectra are fitted according to a warm absorption model N(ism)x N(wind) in combination with a two temperature (APEC) optically thin thermal plasma model of temperatures kT(1)=0.22 and kT(2)=2.62 keV, and the inclusion of six independent broad emission lines. The unabsorbed X-ray flux is about 10.74x10 (exp -13) erg cm (exp -2) s (exp -1) in the 0.4-10.0 keV energy band, leading a Lx/Lbol ratio of about 9.7x10 (exp -7). We confirm the existence of short-term variability, of about 35% of total observed flux, produced by the highly radiative gas at the colliding wind region of the system.