Dust emission from star-forming regions VI. The submillimetre YSO cluster in NGC 2264

We present new submillimetre and millimetre continuum observations of NGC 2 264, in the region of Alien's infra-red source IRS1, at 350, 450, 800 and 1 300 mu m taken with the 15-m JCMT and the IRAM 30-m MRT. We observe a ridge of bright submillimetre and millimetre emission which we designate NGC 226 4 MM. Within this ridge we have discovered a cluster of five submillimetre sources which we label NGC 2264 MMS 1-5. The masses of the sources lie in t he range similar to 10-50M. and each source has a FWHM of less than or equa l to 0.1pc. The total mass of the ridge is similar to 730M.. We identify MMS3 as harbouring the driving source of a previously discovere d bipolar outflow. We note that MMS5 is positionally coincident with a prev iously discovered HST nearir source, but we conclude that this is a chance alignment, since typical extinction values within the ridge lie in the rang e A(V) similar to 200-1600. The cluster which we have discovered is of high er mass and extends over a larger area than the low-mass sub-cluster discov ered by the HST surrounding IRS1. Our continuum maps show a greater dynamic range than molecular spectral line maps, due to gas freezing out onto dust grains at the densities of these sources. We suggest that each of the sour ces MMS1-5 is forming one or more intermediate or high mass stars.