Structural Variation of Molecular Gas in the Sagittarius Arm and Interarm Regions

摘要: We have carried out survey observations toward the Galactic plane at l Almost-Equal-To 38 Degree-Sign in {sup 12}CO and 13}CO J = 1-0 lines using Nobeyama Radio Observatory 45 m telescope. A wide area (0.{sup 0}8 Multiplication-Sign 0.{sup 0}8) was mapped with high spatial resolution (17''). The line of sight samples gas both Sagittarius arm interarm regions. present reveal how structure physical conditions vary across a spiral arm. classify molecular into two distinct components based on its appearance: bright compact B component fainter diffuse (i.e., more extended) D component. is predominantly seen velocities, while dominates velocities also found velocities. introduce brightness distribution function index (BDI, which indicates dominance component) order to quantify map's appearance. radial BDI peaks coincide those 3-2/{sup intensity ratio warm gas) H II regions, andmore » tend be offset from lower presumably downstream side arm). Our that small scales changes arm: spatially confined structures develop arm, leading star formation side, extended emission region.« less