Dust emission from star-forming regions
VI. The submillimetre YSO cluster in NGC 2264
D. Ward-Thompson 1,
R. Zylka 2,3,
P.G. Mezger 2 and
A.W. Sievers 4
Received 13 August 1998 / Accepted 29 November 1999
We present new submillimetre and millimetre continuum observations of NGC 2264, in the region of Allen's infra-red source IRS1, at 350, 450, 800 and 1300µm 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 2264 MM. Within this ridge we have discovered a cluster of five submillimetre sources which we label NGC 2264 MMS1-5. The masses of the sources lie in the range 10-50 and each source has a FWHM of 0.1pc. The total mass of the ridge is 730.
We identify MMS3 as harbouring the driving source of a previously discovered bipolar outflow. We note that MMS5 is positionally coincident with a previously discovered HST near-ir source, but we conclude that this is a chance alignment, since typical extinction values within the ridge lie in the range AV200-1600. The cluster which we have discovered is of higher mass and extends over a larger area than the low-mass sub-cluster discovered 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 sources MMS1-5 is forming one or more intermediate or high mass stars.
Key words: stars: formation ISM: dust, extinction Galaxy: open clusters and associations: individual: NGC 2264
© European Southern Observatory (ESO) 2000
Online publication: March 21, 2000