(Proposal ID) S14B-134

(PI) Miura Rie

(Proposal Title)
 Unveiling Embedded Massive Young Stellar Objects in the GMCs of M33

(Abstract)
Studying massive young stellar objects (MYSOs) embedded within a giant 
molecular cloud (GMC) is key to understand how the massive stars/clusters 
are formed within a GMC (GMC evolution). M33 is one of the best spiral 
galaxies for this study due to its proximity and preferable inclination, 
which allow us to resolve the typical size of clusters and GMCs without 
contamination along the line of sight unlike in our Galaxy. We have recently 
built a catalog of GMC and young stellar groups (YSGs) in M33 based on CO(3-2) 
and optical photometry data, and we have classified these GMCs into four 
different evolutionary stages according to their spatial associations with 
H_II regions, and the ages of the associatedYSGs. In this proposal, we aim 
to identify the missing embedded MYSOs from the color-color diagram based on 
JHK_s images obtained with MOIRCS. We will investigate the distribution of 
these MYSOs within the GMCs, and if their fraction changes along the different 
GMC evolutionary stages. To attain this goal, we propose to carry out MOIRCS 
observations of four selected fields including 44 GMCs on different 
evolutionary stages.