Program: GS-2004B-Q-2

The compact binary supersoft X-ray sources - CBSSs - are a group of stars that are copious sources of supersoft X-ray emission. From stellar population simulations, about 1000 such sources should exist in the Galaxy but only two are observed. It has been proposed that the V Sge stars are the galactic counterpart of the CBSS. This implies that the supersoft X-ray emission is suppressed ? probably by the interstellar medium. One way of testing this idea is by observing nebular emission in the vicinity of the star. With the GMOS-IFU we expect to detect this hypothetical nebulae. If the V Sge stars are, in fact, the galactic counterpart of the CBSS, one would expect a stronger nebular emission in these objects. This represents a critical test for studying the supersoft X-ray source as we do not have other kind of direct access to this source. A second puzzle that is associated to the CBSSs and V Sge stars is the nature of their secondary component. Up to now, no spectroscopic detection of any secondary star in either CBSS or V Sge objects has been published. Our goals are the detection of the nebular emission as well as of the secondary stars in these objects.