2001Mm/Submm images of Herbig-Haro energy sources and candidate protostarsChini, R.; Ward-Thompson, D.; Kirk, J. M.; Nielbock, M.; Reipurth, B.; Sievers, A., Astronomy & Astrophysics 369, p155-169 We present 450, 850 mu m and 1300 mu m images of regions with embedded candidate protostars. Some of them are associated with HH objects (HH 7-11,HH 1-2,HH 147,HH 111,HH 108) and have been previously identified in the course of a 1300 mu m survey. Other regions were taken from the IRAS PSC (04239+2436, 04368+2557, 20050+2720, 20386+6751, 22134+5834, 23011+6126). The new mm/submm images show the detailed structure of the regions some of which contain new compact sources as well as extended emission features. The inferred mm/submm fluxes are combined with IRAS data in order to derive the temperature of the associated dust, its mass and the re-radiated luminosity. Taking the ratio of FIR-to-submm luminosity as an indicator for the evolutionary stage, we find that 15 out of 17 sources have L_FIR/L_smm < 200, indicating that most objects are probably genuine protostars. For the first time, we detect dust emission associated with HH objects themselves, H_2 and CO flows which we interpret as density enhancements swept up by the ejected material. 2000First Observations of the Magnetic Field Geometry in Prestellar CoresWard-Thompson, D.; Kirk, J. M.; Crutcher, R. M.; Greaves, J. S.; Holland, W. S.; André, P., Astronomical Journal 537, l135-138 We present the first published maps of magnetic fields in prestellar cores to test theoretical ideas about the way in which the magnetic field geometry affects the star formation process. The observations are JCMT-SCUBA maps of 850 µm thermal emission from dust. Linear polarizations at typically 10 or more independent positions in each of three objects, L1544, L183, and L43, were measured, and the geometries of the magnetic fields in the plane of the sky were mapped from the polarization directions. The observed polarizations in all three objects appear smooth and fairly uniform. In L1544 and L183 the mean magnetic fields are at an angle of ~30° to the minor axes of the cores. The L43 B-field appears to have been influenced in its southern half such that it is parallel to the wall of a cavity produced by a CO outflow from a nearby T Tauri star, while in the northern half the field appears less disturbed and has an angle 44° to the core minor axis. We briefly compare our results with published models of magnetized cloud cores and conclude that no current model can explain these observations simultaneously with previous ISOCAM data. |