sdO and peculiar X-ray emissions

Some Be stars exhibit a bright and extremely hard X-ray emission, whose origin is debated. In this context, it has been advocated that stripped helium-star sdO companions could play a significant role. Using high quality datasets, we examined (1) the binarity of these peculiar Be stars and (2) the X-ray emission of known Be+sdO systems. In this contribution, we present the result of these two studies and assess their impact on the proposed scenario.