Investigating the origin of the X-ray emission of Cyg OB2 #5 - continuation

Massive stars have strong winds, which collide in massive binaries, giving riseto hard and varying Xray emission. Cyg OB2 #5 is such a case. It was recentlyfound to be a quadruple system and changes in its Xray emission indicate thatsome Xrays arise in the windwind collision (WWC) between the close binary andthe third star orbiting it in 6.7 yrs. In this context, Xrays are a crucialtool to constrain the orbital parameters, but the 6.7 yr orbit is poorlysampled. A monitoring (one observation per year) is thus needed. To continuethis program, we request in this AO a short exposure (10 ks). truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]