演講資訊

摘要：

Finding the youngest protostars and investigating their environment is a critical step toward fully understanding star formation. In this talk, I will present our SMA and ALMA observations of VLA1623. Our data reveal that this "prototypical" Class 0 object is in fact a triple non-coeval system with each source driving its own outflows. In addition, two surprising results are discovered. First, we find a rotating disk-like structure about VLA1623A with indications of pure Keplerian rotation, which is one of the first evidence of Keplerian disk structures around Class 0 protostars. Second, we find VLA1623B to be a bona fide extremely young protostellar object between the starless core and Class 0 stages -- a first core candidate. I will also introduce a new method we developed for identifying faint YSO population in Giant Molecular Clouds using multi-band photometry data. We separate YSOs from the background galaxies in multi-dimensional magnitude space, which is equivalent to using all possible variations of Color-Magnitude Diagrams simultaneously. As a results, we select 28% more YSOs compared to the results of Spitzer's c2d project, and thus Star Formation Rate (SFR) also increases 28%. Compared to theories in Krumholz & McKee (2005), our derived SFR suggests that star formation in large scale is dominated by supersonic turbulence rather than magnetic fields.