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N. H. Volgenau, L. G. Mundy (U. Maryland), L. W. Looney (MPE, Garching), W. J. Welch (UC, Berkeley)
Traditional star formation theories assume that pre-stellar cores have simple shapes (spherical, cylindrical) and simple kinematics (quasi- stationary, uniformly rotating), but observations of cores have always indicated that turbulent motions are relevant and, at times, dominant. Recent theoretical papers (e.g. Ostriker et al. 2001, Burkert & Bodenheimer 2000) have considered pre-stellar cores as interactive and transient phenomena. In this new picture, cores form rapidly, stimulated by dynamic interactions of turbulent cloud material. The cores may remain turbulent and may continue to evolve dynamically during stellar formation.
We have acquired maps of the C18O J=1-0 (110 GHz) and 2.7mm dust continuum emission from the embedded cores NGC1333 IRAS2, NGC1333 IRAS4, and L1448 N to test these discrepant theories. The observations were made with the BIMA millimeter- wave interferometer and the FCRAO 14-m antenna and combined using a maximum entropy method. The combined maps are tuned to resolutions of 10", 5", and 2.5" to reveal the gas distribution and velocity structure on scales from 800 AU to 0.1pc (the approximate size of `coherent cores'). The FCRAO data also show the overall structure of the surrounding clouds. We present an analysis of the velocity fields of these embedded cores and compare the fields with the expectations of quasi-static and dynamic star formation theories.