THE THREE-mm ULTIMATE MOPRA MILKY WAY SURVEY. II. CLOUD AND STAR FORMATION NEAR THE FILAMENTARY MINISTARBURST RCW 106

摘要

We report here a study of gas, dust, and star formation rates (SFRs) in the molecular cloud complexes (MCCs) surrounding the giant H ii region RCW 106 using 12CO and 13CO(1–0) data from the Three-mm Ultimate Mopra Milky way Survey and archival data. We separate the emission in the Galactic Plane around l = 330°–335° and b = ?1°–1° into two main MCCs: the RCW 106 (VLSR = ?48 km s?1) complex and the MCC331–90 (VLSR = ?90 km s?1) complex. While RCW 106 (M) is located in the Scutum–Centaurus arm at a distance of 3.6 kpc, MCC331–90 (M) is in the Norma arm at a distance of 5 kpc. Their molecular gas mass surface densities are ~220 and ~130 pc?2, respectively. For the RCW 106 complex, using the 21 cm continuum fluxes and dense clumps counting, we obtain immediate past (~?0.2 Myr) and immediate future (~+0.2 Myr) SFRs of and . This results in an immediate past SFR density of and an immediate future SFR density of . As both SFRs are higher than the ministarburst threshold, they must be undergoing a ministarburst event although burst peak has already passed. This is one of the most active star forming complexes in the southern sky that is ideal for further investigations of massive star formation and potentially shedding light on the physics of high-redshift starbursts.