[SER2000] SSV 13 , the SIMBAD biblio

We have obtained 850 and 450 µm continuum maps of 21 low-mass cores with SEDs ranging from pre-protostellar to Class I (18 K<T_bol<370 K), using SCUBA at the JCMT. In this paper we present the maps, radial intensity profiles, and photometry. Pre-protostellar cores do not have power-law intensity profiles, whereas the intensity profiles of Class 0 and Class I sources can be fitted with power laws over a large range of radii. A substantial number of sources have companion sources within a few arcminutes (two out of five pre-protostellar cores, nine out of 16 Class 0/I sources). The mean separation between sources is 10,800 AU. The median separation is 18,000 AU including sources without companions as a lower limit. The mean value of the spectral index between 450 and 850 µm is 2.8±0.4, with pre-protostellar cores having slightly lower spectral indices (2.5±0.4). The mean mass of the sample, based on the dust emission in a 120" aperture, is 1.1±0.9 M_☉. For the sources fitted by power-law intensity distributions (I_ν(b)/I_ν(0)=(b/b₀)^m), the mean value of m is 1.52±0.45 for Class 0 and I sources at 850 µm and 1.44±0.25 at 450 µm. Based on a simple analysis, assuming the emission is in the Rayleigh-Jeans limit and that T_d(r)∝r^–0.4, these values of m translate into power-law density distributions (n∝r^–p) with p∼2.1. However, we show that this result may be changed by more careful consideration of effects such as beam size and shape, finite outer radii, more realistic T_d(r), and failure of the Rayleigh-Jeans approximation.