| Star formation is a dynamic and complex activity. In this thesis, we will study characteristic activities in star formation regions: protostellar collapse, bipolar outflow, and large scale rotation.;In Chapter 1, we study a protostellar collapse in a low-mass star formation region. A dark cloud core, B335, is modeled as an inside-out collapse. The radiative transfer code uses the Monte Carlo method. Line profiles for several transitions of CS and ;In Chapter 2, we investigate kinematic structures in a high-mass star formation region. Monoceros R2 dense core region was observed with molecular lines. We suggest that the main part can be explained as a parsec scale toroid around the H scII region with its symmetry axis parallel to the CO outflow and the magnetic field. The ;In Chapter 3, extremely high velocity (EHV) wings are studied with CO lines. The results of our survey suggest that EHV wings are common around infrared sources of moderate to high luminosity in dense regions. Line ratios imply that the EHV gas is usually optically thin and warm. Characteristic velocities range from 20 to 40 km ;In Chapter 4, molecular outflows associated with GL 2591 and W28 A2 were studied with the (C scI) line. Upper limits are set on the (C scI) emission in the EHV line wings. These limits are discussed in terms of wind-driven and jet-driven models of molecular outflows. |
