Abstracto
- We discuss high angular resolution observations of ammonia toward four candidate high-mass starless cores (HMSCs). The cores were identified by the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) during its 2005 survey of the Vulpecula region where 60 compact sources were detected simultaneously at 250, 350, and 500 μm. Four of these cores, with no IRAS–PSC or MSX counterparts, were mapped with the NRAO Very Large Array and observed with the Effelsberg 100 m telescope in the NH3(1,1) and (2,2) spectral lines. Our observations indicate that the four cores are cold (Tk < 16 K) and show a filamentary and/or clumpy structure. They also show a significant velocity substructure within ∼1 km s−1. The four BLAST cores appear to be colder and more quiescent than other previously observed HMSC candidates, suggesting an earlier stage of evolution.