FAR-INFRARED AND SUBMILLIMETER WAVELENGTH OBSERVATIONS OF STAR-FORMING DENSE CORES .2. IMAGES

This paper reports on far-infrared and submillimeter wavelength observations of low-mass protostellar candidates. The data set comprises emission maps of nine sources observed over a wavelength range 100-800-mu-m. The emission is extended at all wavelengths longer than 100-mu-m. The apparent size of the emission regions is weakly correlated with the beam size and is consistent with an underlying specific intensity profile which is scale-free (i.e., I-nu decreases as a power law with distance). The observed emission maps are not circular, but have a mean aspect ratio of 1.3, and the position angles are similar to those determined from maps of molecular emission. The observational results are used in conjunction with theoretical considerations to constrain the physical properties of the putative protostellar envelopes. The best constrained parameter is the sum p + q of the power-law indices of the density and temperature distributions; this sum is shown to lie in the range 1.8 less-than-or-equal-to p + q less-than-or-equal-to 2.3 for the sources L1489 and L1527.