DEEP SUBMILLIMETER CONTINUUM IMAGING OF MCNEIL'S NEBULA

摘要

A protostellar source in the L1630 molecular cloud, previously detected at (sub)millimeter wavelengths, was recently found to show dramatic variability in the optical regime by amateur astronomer J. McNeil. We present deep images of the 350 μm dust continuum emission in the vicinity of McNeil's nebula obtained using the SHARC II bolometer camera at Caltech Submillimeter Observatory. A comparison with our earlier 1300 μm and 350 μm observations indicates an increase in the 350 μm flux density of the source located near the vertex of the nebula between 1997 and 2004. The 350 μm source morphology is that of a spatially resolved source with a FWHM deconvolved source size of ～ 19″ connected to a long, narrow filament, as compared to an unresolved point source in the 1300 μm data. However, these differences may be largely related to the limited sensitivity of the previous measurements and the differences in the observing modes used, namely the improved sensitivity of the new generation, AC-biased detectors to low-level extended continuum emission.