# The Three-mm Ultimate Mopra Milky Way Survey. II. Cloud and Star Formation Near the Filamentary Ministarburst RCW 106

**Authors:** Hans Nguyen, Quang Nguyen Luong, Peter G. Martin, Peter J. Barnes, Erik Muller, Vicki Lowe, Nadia Lo, Maria Cunningham, Frédérique Motte, Stefan N. O'Dougherty, Audra K. Hernandez, Gary A. Fuller  
**arXiv:** [1504.02246](https://arxiv.org/abs/1504.02246)  
**Date:** 2015-04-09  
**Summary page:** https://www.summarizepaper.com/en/paper/1504.02246v1/

## Key points

- Study investigates gas, dust, and star formation rates in molecular cloud complexes surrounding RCW 106 HII region
- Two main molecular cloud complexes identified: RCW 106 complex and MCC331-90 complex
- RCW 106 complex has higher molecular gas mass surface density (220 M_sun/pc^2) than MCC331-90 complex (130 M_sun/pc^2)
- Immediate past SFR of 0.25 +/- 0.023 M_sun/yr and immediate future SFR of 0.12 +/- 0.1 M_sun/yr obtained for RCW 106 complex using continuum fluxes and dense clump counting
- Both SFRs in RCW 106 complex are higher than ministarburst threshold, indicating a ministarburst event has occurred although burst peak has already passed
- RCW 106 complex is one of the most active star forming complexes in southern sky, making it ideal for further investigations into massive star formation and potentially shedding light on physics involved in high redshift starbursts events as well as understanding how massive stars form and evolve under extreme conditions
- Study provides valuable insights into interplay between gas dust and star formation rates in molecular cloud complexes surrounding H II regions while highlighting importance of continued research to better understand processes involved with massive star formation

## Summary

This study investigates the gas, dust, and star formation rates (SFRs) in the molecular cloud complexes surrounding the giant H$\,{\rm \scriptsize{II}}$ region RCW$\,$106 using $^{12}$CO and $^{13}$CO$\,$(1-0) data from the Three-mm Ultimate Mopra Milky way Survey (ThrUMMS) and archival data. The emission in the Galactic Plane around $l=330^{\circ} - 335^{\circ}$, and $b=-1^{\circ} - 1^{\circ}$, is separated into two main molecular cloud complexes (MCCs): the RCW 106 complex with a molecular gas mass surface density of $\sim220 \; {\rm M_{\odot}\; pc^{-2}}$, located in the Scutum-Centaurus arm at a distance of 3.6 kpc; and the MCC331-90 complex with a molecular gas mass surface density of $\sim130 \; {\rm M_{\odot}\; pc^{-2}}$, located in the Norma arm at a distance of 5 kpc. For RCW 106 complex, using 21 cm continuum fluxes and dense clump counting an immediate past ($\sim -0.2 \; {\rm Myr}) SFR of ${0.25_{-0.023}^{+0.09}\; {\rm M_{\odot}\; yr^{-1}}}$, and an immediate future ($\sim +0.2 \; {\rm Myr}) SFR of ${0.12 \pm 0.1 \; {\rm M_{\odot}\; yr^{-1}}}$, are obtained resulting in an immediate past SFR density of ${9.5_{-0.9}^{+3.4}\; {\rm M_{\odot}\; yr^{-1}\: kpc^{-2}}}$, and an immediate future SFR density of ${4.8_{-3.8}^{+3.8}\; 
    {\rm M_{\odot}\: yr^{-1}\: kpc^{-2}}}$. As both SFRs in this cloud are higher than the ministarburst threshold they must be undergoing a ministarburst event although burst peak has already passed. The RCW 106 complex is one of the most active star forming complexes in the southern sky making it ideal for further investigations into massive star formation and potentially shedding light on physics involved in high redshift starbursts events as well as understanding how massive stars form and evolve under extreme conditions . Overall this study provides valuable insights into complex interplay between gas dust and star formation rates in molecular cloud complexes surrounding H II regions while highlighting importance of continued research to better understand processes involved with massive star formation .