The active source in the region of the Herbig star BD+40 4124

We present new near-infrared, millimeter and radio observations of the region associated with BD+40 4124, a Herbig Be star located in the direction of the Cygnus arm. BD+40 4124 is the optically brightest member of a small group of young emission line stars, including V 1318 Cygni and V 1686 Cygni. Near-IR broad-band imaging of V 1318 Cygni reveals the presence of two distinct stellar components oriented north-south, a result recently reported by Aspin et al. (1994). On a larger scale, the near-IR images also indicate the presence of many highly embedded sources concentrated in the vicinity of the bright visible stars. In the central part of the cluster, the near-IR sources outnumber the optically visible ones by a factor of three. The distribution of the high density molecular gas traced by the CS J=5->4 emission is highly concentrated around V1318 and V1686 Cygni, while the total column density of gas traced by the C^18^O J=2->1 shows a ridge morphology centered on these sources. The Herbig star BD+40 4124lies at the edge of both structures. From the otpically thin C^18^O emission, we derive a total molecular mass of M_core_=280Msun_. A molecular outflow has been detected in CO J=2->1. The high velocity gas is confined to a compact region of size =~20", corresponding to a physical length of 0.1pc. The outflow is not well resolved, or collimated, on the observed scales. We have also detected H_2_O maser emission at 22.2GHz at a position coincident with the center of the bipolar outflow. Both the maser and the outflow are located at the position of the southern source V1318 S which we identify as the source responsible for the activity observed in the BD+40 region.