The Cygnus X region. IX. On the hydrogen content of the Cygnus OB2 association.

A search for radio continuum emission at 15 GHz revealed no compact H II region inside the Cyg OB 2 association. We argue that neutral or molecular hydrogen cannot be present inside the association. A large H II region observed as a background component is suggested as the sink for the large amount of Lyman Continuum photons. The gas seems to be depleted relative to dust inside the association.