Kinematics of Ultracompact H II Regions Revealed: High Spatial and Spectral Resolution Mapping of the 12.8 Micron [Ne II] Line in Monoceros R2

摘要: We present the first results of a study kinematics and morphology ultracompact H II regions by using new observational technique. used very high spatial spectral resolution observations (θbm = 14, ΔV 3.4 km s-1) [Ne II] line at 12.8 μm to ionized gas in Monoceros R2. The emission shows an region with highest measure ~24'' diameter shell, surrounded on all sides neutral material. widths are as narrow 8 s-1 some positions. In places where lines complex broader, additional width is most likely due overlap narrower features along sight. themselves, however, broader than purely thermal width. global suggest that 24'' shell expanding ≈10 s-1. This interpretation leads dynamical age for less 104 yr. However, profiles toward brightest part nebula (on southeast side shell) not consistent simple expansion picture. Both bright ridge can be common kinematic pattern which material flows from bottom rim bowl-like feature. High-resolution mid-IR fine-structure transitions offer great promise probe around young massive stars. Once appropriate theoretical modeling larger sample place, it should possible determine physics behind observed systematic motions sources such Mon