The Cygnus superbubble revisited

Abstract

The Orion local spiral arm is seen tangential towards the Cygnus region. Intense radio emission with quite a complex morphology is observed, which appears to be surrounded by strong soft X-ray emission. This remarkable X-ray structure is known as the Cygnus superbubble. We compare a recent 1.4 GHz radio continuum and polarization map from the Effelsberg 100-m telescope with X-ray data from the ROSAT all-sky survey of this area. Including available survey data of the infrared, HI and CO emission, we investigate a number of high latitude features, which are physically related to one of the Cygnus OB associations. These OB associations, however, are located along the local arm at different distances. Our results support the view that the Cygnus superbubble is not a physical unity, but results from a projection of unrelated X-ray emitting features at different distances blown out from the local arm seen along the line of sight.